HomeMy WebLinkAboutI-70 Vail Road Feasibility Study 1994 Feasibility Study
I-70/VAIL ROAD
August, 1994
Prepared for
Gregory A. Hall, P.E.
Town Engineer
Town of Vail
Engineering Department
1309 Vail Valley Drive
Vail, Colorado 81657
Prepared by
Leif Ourston
Leif Ourston & Associates
5290 Overpass Road, Suite 212
Santa Barbara, California 93111
CONTENTS
SECTION DESCRIPTION
FEASIBILITY STUDY
I-70/Vail Road The main text of the study.
APPENDIX A
Proposed Interchange Layouts Drawings of the interchange.
APPENDIX B
Modern Roundabout or
Nonconforming Traffic Circle? A one-page comparison of the two types
of circular intersection.
APPENDIX C
Vail's First Roundabouts A response to concerns about building
roundabouts in Vail.
APPENDIX D
Vail Transportation Master Plan An excerpt of the pages of the plan
related to Main Vail.
APPENDIX E
Main Vail Accident History Diagrams of collisions at Main Vail.
APPENDIX F
Understanding Rodel An explanation of the computer
application used to design Vail's
roundabouts.
APPENDIX G
Roundabout Levels of Service Computations of levels of service,
together with Rodel printouts.
FEASIBILITY STUDY
I-70/VAIL ROAD
SUMMARY
Congestion at the diamond interchange of Interstate Highway 70 and Vail
Road could be corrected by constructing a pair of modern roundabouts at
the ramp and frontage road intersections . The project wouid reduce
accidents and enhance the interchange's appearance. The Town would not
need to acquire right of way or to widen the undercrossing.
The interchange would have ample capacity to operate at levels of service
A and B even if existing flows increase by fifty percent. Accidents would
decrease by about 19 percent following construction of the project.
ROUNDABOUTS AT MAIN VAIL
The diamond interchange of Interstate Highway 70 and Vail Road in Vail,
Colorado, often called Main Vail, is subject to long delays . During peak
traffic demand periods traffic wardens at the intersections north and
, south of the freeway direct traffic to relieve congestion. A proposal to
install traffic signals was rejected by the Town of Vail. Yet the quality
of life in the Town is threatened by worsening traffic congestion at this
interchange and at the interchange of I-70 and Chamonix Road, known as
West Vail.
The Town has commissioned this study of the feasibility of using modern
roundabouts to solve the problem. Unlike nonconforming traffic circles ,
modern roundabouts conform to modern roundabouts guidelines . ( See
Appendix B for a one-page comparison of the two types of circular
intersections .) Since 1990 modern roundabouts have been installed in
about a dozen sites in the United States, including many locations in
Florida, three in Nevada , two in California, and two in Maryland . All are
success stories, reducing delay and accidents.
In the United Kingdom almost all freeway-to-street interchanges are
based on the modern roundabout. Australia, Norway, Sweden , and France
also have modern roundabout interchanaes. Modern roundabout inter-
FEASIBILITY STUDY I-70/VAIL ROAD
changes have been proposed in California. In Maryland one has been
approved by the Federal Highway Administration.
PROJECT DESCRIPTION
At Main Vail two roundabouts would be built (see Appendix A) . The north
roundabout would have an inscribed circle diameter (outer diameter) of
120 feet. It would have a raindrop type of central island , which would
prevent traffic from turning left onto the off ramp. It would provide high
capacity continuous flow for traffic on Vail Road coming from under the
bridge , since this traffic would not have to yield the right of way to
circulating traffic.
All entries to the north roundabout would have two lanes, with 28 feet
between curbs. The circulatory roadway would also be 28 feet wide from
the outer curb to an inner nine-foot wide truck apron. The three-inch high
concrete truck apron would discourage most vehicles from using it,
deflecting and slowing entering vehicles, but the rear wheels of long
trucks would easily mount it.
Both roundabouts are designed to accommodate a 65-foot long tractor and
semitrailer. Long trucks would be able to make 60-foot radius U-turns
from off ramps to frontage roads and from frontage roads to on ramps by
beginning their turns in the left lane.
The connection from the north roundabout to _Spraddle Creek Road is
designed to accommodate a school bus, fire truck, or garbage truck. Right
turns from the roundabout to Spraddle Creek Road would have a maximum
turning radius of 50 feet. Turns by long vehicles would end next to the
road' s north curb.
The south roundabout would have a 200-foot inscribed circle diameter.
Its central island would be 128 feet in diameter. The outer 39-foot wide
margin of the central island would be kept clear of tall objects to provide
adequate forward visibility, but a central area 50 feet in diameter could
be used for landscaping or public art of any desired height.
To provide ample capacity, all but one entry to the south roundabout would
have two lanes. The westbound South Frontage Road entry would have four
lanes. The eastbound off ramp would have a right turn bypass lane in
addition to its two-lane entrv to the roundabout. The circulatorv roadwav
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FEASIBILITY STUDY I-70/VAIL ROAD
would be 36 feet wide through most of the roundabout and 48 feet wide in
front of the four-lane entry.
Splitter islands would be notched to allow pedestrian refuges 10 feet
wide . Following modern guidelines, crosswalks would not be marked .
Walkways wouid be designed where necessary as part of the landscape
plan to align with the pedestrian refuges in the splitter islands.
TRAFFIC PERFORMANCE
A number of alternative roaci improvements were studied by Felsberg Holt
& Ullevig and presented in the Vail Transportation Master Plan (see
Appendix D) . The preferred alternative is Alternative 8, given on their
page number 78 . This would remove the two east ramps at Vail Road and
direct traffic needing this connection to ramps east of Vail Road in the
Booth Falls area.
The study determined that the present volume/capacity ratio at the
intersection of Vail Road and the westbound ramps is 1 . 16 , level of
service E. At Vail Road and the eastbound ramps and South Frontage Road
the present volume/capacity ratio was determined to be 0. 94 , also level
of service E, if traffic wardens or demand responsive traffic signals are
used (see their page number 74) .
The performance of modern roundabouts at the ramp and frontage road
intersections with Vail Road was -estimated using a computer application
named Rodel . (See Appendix F for an explanation of Rodel . ) Rodel
estimates average delay in minutes per vehicle . By use of a little
spreadsheet this was translated to average delay in seconds per vehicle
and to the corresponding levels of service (see Appendix G) . The Highway
Capacity Manual relates levels of service to average delay for the whole
intersection according to the table on the following page.
3
FEASIBILITY STUDY I-70/VAIL ROAD
LEVEL OF SERVICE FROM AVERAGE
STOPPED DELAY AT INTERSECTION
Taken from Table 9- 1 of the
Highway Capacity Manual
STOPPED LEVEL OF
DELAY SERVICE
(SEC/VEH)
d<= 5 A
5 <d<= 15 B
15 <d<=25 C
25 <d<=40 D
40<d<=60 E
60<d F
Both roundabouts would operate at levei of service A with existing
traffic. The roundabouts were designed to allow a traffic increase of at
least fifty percent because it is thought that some longevity would be
necessary to justify the substantial investment required for this project.
Also, traffic surges of an unknown amount, perhaps fifty percent or more ,
presently occur at various times each year.
With a fifty percent increase in traffic, the north roundabout would
continue to operate at level of service A, but the south roundabout would
operate at level of service B. Levels of service are presented in the table
below.
AVERAGE DELAY LEVEL OF SERVICE
(Seconds Per Vehicle)
North R. South R. North R. South R.
TRAF I ED MAND B, M, p,�, Q,b,, p�1,, �M, p.., A�, �, p�d,
100% of Existing Traffic* 2 . 2 1 . 8 3 .4 3 . 2 A A A A
150% of Existin Traffic 3 .0 2. 8 11 . 8 11 . 5 A A B B
*" Existing traffic" in this report refers to counts made on the twenty-
fifth busiest ski day of the year (per Vail Associates), in March of 1990.
The design objective of allowing a fifty percent increase in existing flows
will be exceeded. The following percent increases in existing traffic will
be oossible without exceedina averaae stonned delav of 30 seconds eer
- r -J -�J - 1 T - ! - �
4
FEASIBILITY STUDY I-70/VAIL ROAD
vehicle on any leg ( a measure of practical capaeity) , estimated at the 85th
percentile.
ROUNDABOUT A. M. P. M.
Main Vail North 117% 65 %
Main Vail South 52% 56%
SAFETY
In those countries that have adopted the modern roundabout as a standard
type of intersection , the roundabout is generally regarded as the safest
type of intersection on earth . Typically, accidents at roundabouts are
around 55 percent less than at cross intersections of similar flows
regulated by traffic signals. Serious injury and fatal accidents are
reduced by more than property damage only accidents according to reports
from all countries, typically by 80 to 90 percent when a signalized
intersection is converted to a modern roundabout.
But all-way STOP sign regulated intersections, as at Vail' s four-way, also
have an excellent safety reputation , at least in general . Two-way STOP
sign regulated intersections , like the two ramp intersections in this
project, generally are not so safe as all-way stops . At Vail Road the
reverse is true . The two-way STOP sign regulated intersections
experience fewer accidents than the four-way intersection of Vail Road
and South Frontage Road, perhaps because of the four-way's heavier flows.
The accident history of modern roundabouts in the United States has been
similar to the success stories of roundabouts in foreign countries.
Accidents have fallen 44 percent for the first eight months of operation
of the Long Beach roundabout in California. This is in contrast to the same
eight months of the previous three years , when the circular intersection
operated as a nonconforming traffic circle. In Santa Barbara , California,
the Five Points roundabout replaced a five-way STOP sign regulated
intersection . Accidents previously averaged about four per year. During
the first six months of roundabout operation, there were three reported
accidents, all at night (the roundabout has poor street lighting) . There
have not been any accidents reported in the last 14 months . The first
modern American roundabouts, built in Las Vegas in 1990, have very low
flows. Nevertheless, it is comforting to note that no accidents have been
reported at them. As far as this author knows, there has never been a
6icvcle or nedestrian accident at a modern American roundabout; but there
have been two motorcycle accidents.
5
FEASIBILITY STUDY I-70/VAIL ROAD
Roger D. Gilpin , of the Colorado Department of Transportation, prepared a
report of all accidents at both the Main Vail and West Vail interchanges
with Interstate Highway 70 over the three-year period of 1991 - 93 .
Appendix E contains the portion of his report that pertains to Main Vail.
Eighty-seven accidents were reported at this interchange over the three-
year period. Of these, 62 were intersectional. The remaining 25 accidents
would not be affected by the modern roundabouts proposed to replace the
existing ramp and frontage road intersections.
At the intersection of the westbound ramps and Vail Road, which would be
replaced by the north roundabout, 14 accidents were reported in the study
period. At the two Vail Road intersections to be replaced by the south
roundabout, the eastbound ramp and South Frontage Road intersections, 48
accidents were reported during the study period.
A large proportion of the 62 intersectional accidents, 27 accidents, were
rear-end accidents, many of them involving vehicles sliding on ice into
stopped vehicles. The roundabouts would not do anything to prevent icy
conditions , but they would greatly reduce the number of vehicles stopped
in queue. The potential for accidents between vehicles which are stopped
and vehicles behind them which can not stop would be reduced as the
roundabouts reduce queuing .
During the study period there were no pedestrian accidents, no motorcycle
accidents , and two bicycle accidents . Modern roundabouts have an
excellent reputation for reducing accidents involving most types of road
users--trucks , cars, buses, and pedestrians--but not motorcycles and
bicycles. Special bypass roads and lanes for bicycles have not been shown
to reduce bicycle accidents at roundabouts. Based on British studies of
similar roundabouts, it is estimated that the number of bicycle accidents
would rise about 50 percent, perhaps by one accident in three years. It is
estimateci that all oth� r types �f �ccident� w��ld d�crease , to a total of
around 50 accidents in three years, for a net reduction of about 12
accidents. This would be a 19 percent reduction in accidents following
construction of the modern roundabout interchange.
SPECIAL ISSUES
Soecial is�ues annlicable to modern roundahouts in Vail are considered in
- .- - - - - - - - - -.- , - -- - - - - - - - - - - - --
Appendix C, "Vail' s First Roundabouts. " Among other issues discussed in
6
FEASIBILITY STUDY I-70/VAIL ROAD
this appendix are the following : snow and ice , tourists unfamiliar with
roundabouts , lighting , signing , maintenance , trucks , buses , bicycles ,
pedestrians, flow fluctuations, potential traffic growth, landscaping , and
emergency vehicles . The roundabouts will give good service with regard
to all of these issues.
CONCLUSION
A modern roundabout interchange to replace the diamond interchange of
Interstate Highway 70 and Vaii Road is feasibie . Unlike alternatives
previously proposed , it would allow all present traffic movements to
continue using the interchange . It would provide an excellent level of
service, reduce accidents, and create a beautiful entry to Vail.
7
APPENDIX A
Proposed Interchange Layouts
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APPENDIX �
Modern Roundabout or
Nonconforming Traffic Circle?
MODERN ROUNDABOUT OR NONCONFORMING TRAFFIC CIRCLE?
Uniike nonconforming traffic circles, modern roundabouts conform to modern
roundabout guidelines. Among other important new features, modern round-
abouts have yield at entry, deflection, and (often) flare, as illustrated below.
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MODERN ROUNDABOUT NONCONFORMING TRAFFIC CIRCLE
1 . Entering traffic yields to circu/ating 1 . Entering traffic cuts off circulating
traffic. traffic.
• Circulating traffic always keeps • Circulating traffic comes to a dead
moving. stop when the circle fills with
entering traffic.
• Works well with very heavy traffic. • Breaks down with heavy traffic.
• No weaving distance necessary. • Long weaving distances for merging
Roundabouts are compact. entries cause circles to be large.
2. Entering traffic aims at the center of Z. Entering traffic aims to the right of
the centrai island and is deflected the central island and proceeds
slow/y around it. straight ahead at speed.
• Slows traffic on fast roads, reducing • Causes serious accidents if used on
accidents. fast roads.
• Deflection promotes the yielding • Fast entries defeat the yielding
process. process.
3. Upstream roadway often flares at 3. Lanes are not added at entry.
entry, adding lanes.
• Provides high capacity in a compact • Provides low capacity even if circle is
space. large.
• Permits two-lane roads between • For high capacity, requires multilane
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APPENDIX C
Vail's First Roundabouts
VAIL' S FIRST ROUNDABOUTS
Prepared for Greg Hall, P. E.
Town Engineer
Town of Vail, Colorado
by Leif Ourston, P. E.
Leif Ourston & Associates
Santa Barbara, California
August 24, 1994
This report addresses thirteen concerns given in your letter of
January 14, 1994 . These important is�ues will be considered
as you decide where and how to build the town's first modern
roundabouts.
1 . How do roundabouts work in extremely snowy climates, in which
pavement markings are covered for stretches at a time, signs may be
obstructed by wind packed snow, and grades may exceed roundabout
standards and may be snow packed and icy?
We have heard from Professor Ragnvald Sagen, speaking to the Town of
Vail by way of a videotape made in Norway two weeks before this year' s
winter Olympic games, standing in front of a roundabout after the deepest
snow Norway has experienced in thirty years . He told us that snow
impairs the performance of all types of intersections, but it seems to
impair modern roundabouts less than others. Snow removal equipment can
clear a roundabout in one forward circular movement. At cross
intersections, it takes several back and forth movements to clear the
middle.
The potential for a head-on or angle type of accident is much less at
modern roundabouts than at cross intersections, in snow, ice , and other
weather. The geometry of roundabouts requires slower speeds. Accidents
tend to be of the less serious merging type.
In the iciest conditions, motorists can not completely stop at STOP signs.
They slowly roll into the intersection . The YIELD signs of roundabouts
arrnmmnrlate thic tvne nf entrv_
........ . . .. . .___ '_ '. .._ y r _ _ ' _" " � '
Vail's First Roundabouts Z
The four-way STOP sign regulated intersection of Vail Road and South
Frontage Road experiences many tail-end icy weather accidents caused by
motorists sliding into vehicles stopped at STOP signs. Since the modern
roundabout proposed for this intersection will have very little queuing ,
there will be fewer rear-end accidents during icy conditions.
In your video, Snow at Roundabouts, we observed some snow packed YIELD
signs at roundabouts, but the triangle-shaped YIELD signs were still easily
recognized. We observed many roads on which the pavement markings,
including yield lines , were completely covered by snow. Entering
motorists understood where to yield the right of way to circulating
traffic because of tracks in the snow and because the roadways were
defined by plowed areas.
Grades should ordinarily not exceed 2 % at roundabouts because truck
drivers may set their circulating speeds based on comfort at a part of the
roundabout where the crossfall if favorable, and they may shed their loads
or roll their trucks where the crossfall changes abruptly to adverse
superelevation . Grades at three of your four roundabouts will meet this
2 % recommended maximum, which feels nearly flat on ice, snow, or wet or
dry pavement. At the main Vail north roundabout, a raindrop-style central
island will prevent trucks from circulating around the bottom of the
roundabout, where the crossfall would be about 4. 5 %. Therefore grades at
all of your roundabouts will meet modern roundabout standards.
Because of their success, modern roundabouts are proliferating in very
snowy countries , including Norway, Switzerland, and Sweden . Two
roundabouts in the United States, in Maryland, have done very well through
recent heavy snow storms, even though the roundabouts are new to the
drivers of their state.To check on this, you may call the traffic engineers
in charge of the roundabouts in Gaithersberg and Lisbon, Maryland. They
are:
011ie Mumpower, P. E.
Traffic Engineer
Department of Public Works
City of Gaithersburg
800 Rabbitt Road
Gaithersburg, Maryland 20878
301 258-6370
and
Vail's First Roundabouts 3
Gene R. Straub
Assistant District Engineer--Traffic
Maryland State Highway Administration
Traffic Engineering Division
P.O. Box 308
Frederick, Maryland 21701
301 694-2595 .
2. Can a motoring public, the majority being on vacation, whose a/ertness
is altered by the fact that they are vacationing and are unfamiliar with
where they need to go anyway, be able to comprehend and properly use a
non-traditional traffic control system such as roundabouts?
Yes. Your roundabouts will be designed for first-time users, because even
years from now many of the visitors to Vail will never have driven a
modern roundabout and will not be expecting one at the end of an off ramp.
There will be several visual cues of the roundabout ahead, the yielding
process , and the one-way circulation around the central island . The
circular patterns of the roundabouts will be seen far in advance at the
bottoms of the off ramps . YIELD AT ROUNDABOUT warning signs will
announce the roundabouts ahead and the need to yield the right of way at
them. Below the standard YIELD signs the international standard round
plate, called a roundel, with a dark blue field and three white arc arrows,
wiil indicate that one must yield the right of way to a stream of traffic
circulating to the right.
On the pavement a broken white yield line of three-foot marks and three-
foot gaps will delimit the interface between entering and circulating
streams of traffic. Lines separating entering lanes of traffic will end at
the yield line, as they do at stop bars next to STOP signs and at limit lines
at traffic signals, conveying to the motorist that he is entering a crossing
stream of traffic. In each lane of traffic a YIELD legend will be painted.
In the central island one-way signs will be erected below the in -
ternational standard internally illuminated one-way sign , a round sign
having a blue background and a white arrow pointing to the right.
Directional signs will guide motorists to their destination much better
than is done by the present signing system. Map-type diagrammatic signs
in advance of the roundabouts on each approach will give the sequence of
route names where the motorist may exit as he circulates around the
rounaabout. At eacn exit irom in� rounaaoou� �n��� n� m�� wiii i��
repeated or� a roundabout exit sign. These exit signs will also give
Vail's First Roundabouts 4
destinations . In some cases further directional information will be given
on directional signs downstream from the roundabout.
We have observed first-time drivers at two recently opened modern
roundabouts in California. The Five Points roundabout replaced a five-way
STOP sign regulated intersection in Santa Barbara in November of 1992 .
The roundabout was the first that most drivers had ever seen. For the
most part they drove it skillfully and correctly the first time through, but
if one watched carefully, he could see some mistakes, and even today
there are a few first-time drivers who make mistakes.
The mistakes have not led to increased accidents. They tended to involve
too much courtesy and hesitation, not too much aggression as had been
predicted . Circulating drivers sometimes stopped to wave entering
drivers into the roundabout in front of them, thus stopping the circulating
stream, which should never be interrupted. Entering drivers sometimes
paused too long at the yield line even when there was no traffic to pause
for. Slow learners benefited from the majority of drivers who showed the
correct way to drive a roundabout. Occasionally there was even a wrong
way movement, but at a circulating speed of twelve miles per hour, it was
easy for motorists to adjust to the mistakes of others.
The prediction before opening the roundabout was that there would be an
initial blood bath until motorists got the hang of it, but eventually things
might settle down. The previous situation had about four accidents per
year. During its first six months of operation the Five Points roundabout
had three reported accidents, all of them at night. It has very bad street
lighting, not up to modern roundabout standards . This situation , and
perhaps the nighttime accidents, will be corrected when the roundabout,
which is made of temporary materials , is replaced with permanent
materials. On the other hand , the problem may have already been
corrected, as the there have not been any accidents, day or night, after the
first six months of operation . The modern roundabout has either
eliminated daytime accidents or greatly reduced their frequency.
The Long Beach roundabout was completed June 30, 1993 . Processing
4, 700 vehicles during the peak hour, this high volume circular intersection
used to average about 40 accidents per year. The project added YIELD
signs to the two previously uncontrolled Pacific Coast Highway entries. It
also widened all entries to three or four lanes and removed lanelines from
the circulatory roadway.
Vail's First Roundabouts 5
The prediction from opponents to the project was that motorists who had
never yielded the right of way during the circle 's 55 years of existence
would not be able to change their ways. Especially feared was the
southbound Pacific Coast Highway approach, which entered the circle on a
seven percent down grade . The prediction from Caltrans, who built the
roundabout, was that it would reduce the amount of white knuckle driving
and clear up some queuing, but that accidents would remain about the
same. The prediction by the consultant was that accidents would be
reduced by about 40 percent. As a matter of fact, during the first eight
months of operation accidents have dropped 44 percent compared to the
same eight months of the previous three years.
Apart from signs warning that entering traffic would have to yield the
right of way at a future date, there was no driver education for the
project--no newspaper spots or television announcements . On the
changeover day some drivers were observed to run the YIELD signs before
the yield lines and legends had been painted . After the yield lines and
legends were painted, no one was observed to run the yield signs on the
changeover day, although occasionally this has happened on days since.
(This experience leads me to believe that the yield lines and legends are
essential visual cues . It wil► be up to the Town of Vail to keep their
pavement markings up, even though snow p►ows tend to obliterate them, if
the Town wants its roundabouts to operate safely for years to come ,
through all seasons. )
The project has been a tremendous success. With less than five seconds
average stopped delay per vehicle, the roundabout operates at level of
service A all day long . Queuing has been eliminated from within the
circle, and short peak hour queues on the approaches quickly dissipate.
The Long Beach roundabout appears to be the most efficient intersection
on Pacific Coast Highway, where queuing exists at all other major
intersections all day long . Video taken on changeover day shows smooth,
skillful operation with few mistakes.
What we have observed with both projects is that there are some
mistakes from first-time users , but these mistakes do not lead to
increased accidents. The slow, one-way natuPe of traffic circulation at
modern roundabouts causes them to be very resilient to mistakes. Modern
roundabouts in this country reduce accidents just as they have done in
every country to which modern roundabouts have been introduced in recent
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Vail's First Roundabouts 6
yet accident reduction prevailed over mistakes , even during the first
months of operation .
3. How will those motorists who are very familiar with using the
roundabouts once installed, and who drive very aggressively, interact with
the much more timid first-time user?
Skillful drivers will honk their horn , but they will not ram timid , less
skilled users. At Long Beach and in Santa Barbara we have observed on-
the-road driver training of first-time drivers by more skilled drivers . The
more skilled drivers honk at those who make mistakes. From this self-
adjusting process skillful drivers are produced.
Since queues and delay are very short on the approaches to modern
roundabouts, there is no need for entering aggressive motorists to cut off
circulating timid motorists . It is easy and convenient to simply wait
one's turn.
4. How can overhead lighting and proper signing be accomplished in an
aesthetically pleasing way, yet sti11 meet proper standards and be
effective?
Good lighting is critical to the roundabouts' success. It is essential that
overhead lighting alert the approaching motorist in advance that he is
entering a roundabout, as he may miss advance warning signs . Good
overhead lighting is also essential to protect cyclists, motorcyclists , and
pedestrians.
Street lights ringing the roundabouts will be equally spaced from each
other and from the center. The exits will be lighted at least 200 feet
from the roundabouts . Horizontal illuminance will be at least 0. 9
footcandle , a somewhat bright standard compared to the illuminance of
conventional intersections. Roughly thirty streetlights will be provided
to light the whole interchange. The lights on Christmas trees at the four-
way STOP sign regulated intersection at Main Vail will be dimmed or
raised or eliminated so that they to not cause the motorist to look into a
wall of light at eye level.
Good signing is also important, both to prevent accidents and to make the
first-time user's experience of the roundabout and of the Town of Vail a
pleasant one. Good signing, as described under question 2 , above, will
nran� rc thm m�tnrict fnr tha rn� �nrlahniit n� �irla him thrn� �nh tha munrlahnut _
M• "M" '
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and guide him to his desired destination within Vail. A signing expert,
Vail's First Roundabouts 7
Fred Hanscom of the Transportation Research Corporation of Haymarket,
Virginia , will help develop a sign plan that provides essential user
information when it is needed while avoiding information overload.
Signing and lighting designs will be brought to the Town of Vail before
implementation to be sure that signs and lights wiil be both effective and
aesthetically pleasing . Adjustments in the designs will be made to meet .
Vail's requirements.
5. How will maintenance efforts be altered with regard to pavement
markings, which are worn very easily by sanding abrasives.
It is essential to keep pavement markings at roundabouts and on their
approaches and exits bright and clear right through the winter and all year
long. Snow removal and the use of sand and salt on the roads will not be
altered on behalf of roundabouts.
What will be altered is the type of markings and the frequency of their
maintenance . Long lasting materials, such as thermoplastic, cold plastic,
and embedded plastic, will be used where necessary in lieu of paint. The
scheduled maintenance cycle may be shortened from one year to half a
year. Earlier unscheduled maintenance will be done as necessary when
stripes show unexpected wear.
The use of high-priced pavement markings and more frequent maintenance
of them are necessary expenses of successful modern roundabouts. There
are offsetting cost savings compared to other types of interchanges and
traffic control. For example, high capacity will be achieved by the round-
abouts without widening the undercrossings, a multimi�lion dollar cost.
6. How easily can truck traffic and bus traffic function through all of the
turning movements?
The roundabouts will be designed to cater to large trucks and buses. At
the north roundabout of Main Vail, around the central island and along the
right side of North Frontage Road and the on ramp, three-inch high
concrete mountable aprons will be constructed. The rear wheels of truck
trailers can safely roll over mountable aprons , but motorists are
discouraged from driving on them. The aprons will be designed to
accommodate snow removal operations.
II_t� �rnc hntumcn frnnt�no rnarlc anrl ramnc will he facilitaY�d hV bV��S�
. v �a� � � �.s v�. � .. vv. . . � ... . ...�y.. . ......... .. . ... . .�. .�,.� "' ... _ _ " """"_ ` ' � — � r — _ _
lanes in west Vail. The distance between ramps and frontage roads is too
Vail's First Roundabouts $
short for some of the largest trucks to make these turns now. The
roundabouts will offer truckers an alternative to present tight U-turns.
They may simply drive all the way around the roundabout, from which they
can easily exit to the frontage road or ramp using a longer turning radius.
7. How wil! bicycles and pedestrians be safely transported through the
intersections?
Bicycles will enter the roundabouts and circulate through them, mingling
with other traffic. Painted bike lanes have been tried in some European
countries, without success. In Netherlands , in which modern roundabouts
are reported to have reduced bicycle and pedestrian accidents as well as
accidents to all other road users , the only fatalities suffered at
roundabouts according to a 1992 report all involved trucks exiting the
roundabouts and driving over cyclists who wished to continue ahead by
circling the roundabout in marked bike lanes . The marked bike lanes may
have given cyclists a false sense of security.
Peripheral bike roads have been used at roundabouts , but there is no
information as to whether they improve or worsen cyclist safety. Vail' s
roundabouts will have up to six legs each, with little space between them,
so that a peripheral bike road would carry the cyclist only a very short
distance before being interrupted by another spoke road . Therefore no
special bicycle facility will be provided at Vail' s roundabouts. At Main
Vail bike lanes will be painted between roundabouts along Vail Road under
the freeway.
Reports on bicycle safety at roundabouts are mixed. A 1986 British study
found cyclists to be at greater risk at circular intersections , but the
study did not differentiate nonconforming traffic eircles ( ciPeular
intersections that do not conform to modern standards) from modern
roundabouts (which do follow modern design standards) . The study found
concentrations of bicycle accidents at entries that did not have adequate
deflection. Good deflection is the principle safety requirement of modern
roundabout design. A more recent study of miniroundabouts in Britain
found that bicycle safety at miniroundabouts is about equal to bicycle
safety at signalized intersections. A recent Dutch study found that
bicycle and pedestrian accidents both declined when conventional
intersections were replaced by small, one-lane Dutch-style roundabouts.
�edestrians will cross th@ entries to the roundabouts in two stages ,
.,o � ��i.,n o+ � mnrli�n enli++er icl� nrl hafnra rmm�latinn tha cPrnnrl Stal7e of
t..ou.an .y u � .. � �..� � .. r.�� � ...� �..�.. . ... .... . ... .. ..., . .�,,.., .. .� ... ._ _ ___ " _ _ '_a _ _ '
crossing . In this way the pedestrian gives all of his attention to traffic
Vail's First Roundabouts 9
flowing from only one direction at a time , and his crossing distance is
divided into two halves , making gaps in traffic easier to find . All
research suggests that the modern roundabout is the safest type of
intersection for pedestrians.
8. How well do roundabouts designed and constructed for handling our
future peak demands operate when the seasonaJity of demand fluctuates to
very low volumes?
You have very large infrequent peak traffic demands in Vail, when it takes
more than an hour to enter the freeway. Your roundabouts will be designed
to reduce the number of these times per year when capacity is exceeded.
We will seek to eliminate these frustrating times altogether. Therefore
the capacity of your roundabouts will be high for normal daily traffic, and
their capacities will far exceed your needs during low traffic periods.
Operationally, you will be very proud of how your roundabouts operate
during normal peak periods and during periods of very low traffic demand .
The lighter the traffic demand, the easier the roundabouts will be to
negotiate . The roundabouts' easy low volume operation is similar to the
ease of operation of other high capacity intersections during periods of
very low traffic demand.
9. Can the roundabouts be constructed as low cost, temporary facilities
to show they can handle the traffic effectively, yet be removed or made
permanent in the same season?
Yes. But I do not recommend temporary roundabouts, for a number of
reasons. If you skimped on cost, you might also skimp on safety, omitting
street lighting and backlit signing , for example . You would almost
certainly skimp on landscaping if you used temporary materials initially,
and your trial roundabout might look like a mess.
Temporary roundabouts would also give the impression that we do not
know what we are doing , and this would be a false impression. We do
know what we are doing, and the roundabouts will be hugely successful, to
the credit of everyone associated with them. Temporary roundabouts
could be resisted with the fear that we would be experimenting with
people' s lives . The Vail roundabouts will not be experiments or
demonstrations. They will be permanent integral parts of your road
system, a source of pride for years to come.
Vail's First Roundabouts � �
] 0. Can a !ow cost temporary solution be tested through a winter season ?
Yes. But I do not wish to be associated with temporary roundabouts, for
the reasons given under question 9 , above.
11 . If future traffic projections are inaccurate and Vail's traffic volumes
continue to grow at alarming rates, at what level do the improvements
fail to satisfactorily function ?
It was felt that the large investment required by this project demanded
that the improved interchange have substantial longevity. The remodelled
interchange should also be able to accommodate the infrequent, irregular
bursts in traffic demand that sometimes cause great delay here. Our
design objective was therefore to design the interchange so that both peak
hour flows on both roundabouts could increase proportionally by at least
50 percent. With the present design, we will meet that objective.
According to the roundabout analysis program Rodel, the following percent
increases in existing ( March of 1990) traffic will be possible without
exceeding average stopped delay of 30 seconds per vehicle on any leg (a
measure of practical capacity), estimated at the 85th percentile.
ROUNDABOUT A.M. P. M .
Main Vail North 117% 65%
Main Vail South 52% 56%
The British research on which Rodel is based was found to closely predict
delay at the Long Beach roundabout in California, where observed average
stopped delay per vehicle was within one second of predicted delay.
Therefore the above estimates are probably close.
12. Show how any proposed landscape features do not obstruct traffic and
maintenance functions.
Plants must be kept low in areas where drivers' visibility is required. In
these same areas some signs are allowed, but their panels must be kept
high enough for drivers to see under them. The exact clear areas, together
with maximum height of plants and minimum height of sign panels , will be
marked on drawings that I submit.
Small central islands must not have any trees or other tall plants. In Vail,
i _ _ .. ��_ _ __ _ e _ . i _ � � _ _ . .iL __ . . _ J _ L _ . . a _. .: u L.... ... .. .... ..a.wl irl.. n.�l Inr..e
onry tne main vaii sou �n � uu � �uauvu � wru na �c a �cuuai �� �a � �u �aiyc
Vail's First Roundabouts 11
enough for trees or sculpture. The cylinder on the central island within
which tall things may grow or be erected is fifty feet in diameter.
73. Finally, the biggest issue, convince skeptics on how wel! roundabouts
will work in handling Vail's current and future traffic volumes and the
characteristics of this vo/ume in all types of circumstances, without
building one before hand.
The narrator of your video, " Snow at Roundabouts, " is Professor Ragnvald
Sagen . He told me that in the early eighties , with the help of Frank
Blackmore of Britain's Transport and Road Research Laboratory, he brought
the concept of the modern roundabout to Norway. They began in Bergen in
west Norway. When they got to east Norway, the skeptics there told them,
"Well of course it works in west Norway, but it would never work in east
Norway. " Nevertheless, one was built in east Norway, and it worked well,
and now hundreds of them are working all over Norway.
We have similar reports of early resistance from very high-level ,
intelligent decision makers, from Australia and Netherlands . Upon opening
of the road system' s first roundabout, after accidents fall , skepticism
gives way to unbridled enthusiasm, and roundabouts spread. This pattern
is seen in all of the countries where the modern roundabout revolution is
under way. The same pattern is beginning here in California, and I am sure
Colorado's initial skepticism will change to enthusiastic support.
When I first became very active in promoting modern roundabouts, in
1983 , France had ignored the phenomenal roundabout success story going
on across the English Channel. Now France is the world' s biggest builder
of modern roundabouts, building more than 1 , 000 per year. I expect to see
the time in the not too distant future when the United States, with three
times the population of France, builds 3 ,000 modern roundabouts a year.
The modern roundabout interchange is now the standard type of
interchange in France and Britain. I expect it to become the standard type
ofinterchange here.
A picture is worth a thousand words. A video is worth a thousand
pictures. But a modern roundabout on your own road system is worth a
thousand videos. Multiplying these thousands together and by the two
roundabouts you will build in Vail , I estimate that you will have a
testament to modern roundabouts worth two billion words . There is
nothing I can say to equal that.
Vail's First Roundabouts � Z
14. Do fire trucks and other emergency vehicles have a problem getting
through roundabouts?
I suggest that anyone concerned with this problem call a fire station in
Britain and ask a fireman that question . I called the fire department in
Swindon at 011 44 21 359-5161 and talked to Fire Fighter Burns. I
questioned him over and over in different ways, and took the following
notes as he spoke.
"No problem. "
"They never block it. "
"There shouldn't be any problems. "
"Not everyone gets out of the way, but the majority do. "
"Hardly ever have a problem."
APPENDIX D
Vail Transportation Master Plan
Vail Transportation Master Plan Chapter VI
MAIN VAIL INTERCHANGE ALTERNATIVES
The range of alternatives for the Main Vail interchange is summarized in Table I1 . Shown are
alternatives that have been previously considered for Vail as well as new and modified alternatives
and supplemental improvements. Table 12 shows the Main Vail interchange alternatives diagrammati-
caily. _
An initial screening of the Main Vail interchange alternatives yield several that should be omitted
from detail analysis. The following illustrates which alternatives are no longer considered and the
reasoning for omitting it.
o Alternative 1 - Close Vai! Road at 4-Way Stop
This alternative would force Vail Road traffic to reroute along East Meadow Drive to Village
Center Road in order to reach the Frontage Road. Traffic would be detoured through a
pedestrian area. "De-pedestrianizing" East Meadow Drive has been considered unacceptable
and is sufficient reason to drop this alternative from detailed analysis.
o Allernative 2 - Single Pornt Diamo�:d (Urban)
This alternative would alleviate some of the intersection spacing concerns, but it would have
IitUe affect on operations at the 4-way stop intersection. Therefore, any benefits that would
be gained by this alternative would not be justified by its excessive cost.
o Alternative 4 - Relocate Eastbound Entry Ramp
This alternative will simpli£y some of Yhe traffic operations that are occurring under the
interchange, but basic travel patterns will not differ significantly and the 4�way stop
intersection will remain congested.
o Alternalive 5 - High Capacity Diamond
This alternative provides minimal operational benefiu but it will not improve turning
movements off the ramps nor will it have any affect on operations at the 4-way stop
intersection since its travel patterns would not change. Therefore, this alterna[ive is dropped
from further evaluation.
o Allernative 6 - Relocate Easlbound and Westbound Entry Ramps
This alternative has the same impact as Alternative 4 along the south side of the interchange
and would further enhance north ramp intersection operations. However, basic travel patterns
will not be altered significantly and the 4-way stop intersection will still be congested during
peak periods.
The remaining alternatives (3, 7 and 8) have been evaluated as to theie impact on interchange
operations. Table 13 shows the vo(ume-to-capacity ratios at key inteesections for each alternative.
In addition to the 4-way stop and ramp intersections, other intersections are presented whose
operations are an important consideration in evaluating each alternative.
Town of VaN Page 70
_ Vai� Transportalion Master Plan Chapter VI
Table il
Main Vail Interchange Design Alternatives
Alternative Comments
Previouslv Considered Alternatives (s)
0. No Action Used as base case for comparative analysis.
I . Close Vail Road at 4-Way Stop To be re-evaluated in teems of the entire I-70
2. Single Point Diamond (Urban) access system for the long-range transportation
3. Remove/Modify EB Exit Ramp; plan
Provide New Ramp(s) at VA Shops
4. Relocate EB Entry Ramp
5. High Capacity Diamond
(*) Traffic signals were proposed to be included in all of the alternatives previously considered.
New or Modified Alternatives
6. Relocate EB and WB Entry Ramps
7. Extend North Frontage Road East
8. Relocate East Ramps to Existing
Underpass East of Golf Course
(Modified Split Diamond)
Su�nlemental Actions Previouslv Considered
9. Frontage Road Modifications While not recommended as isolated alternatives,
(One-Way, Widen, Relocate) 4hese actions are an integral part (in varying
10. Additional I-70 Crossings degrees) of any future improvement option.
I 1 . Signing Modifications
12. Expanded Peripheral Parking
13. Expanded Bus Services
14. Manual Traffic Coatrol
Town of VaA Pa98 ��
Vail Transportation Masier Plan Chapter VI
Table 12
Main Vail Interchange Design Alternatives
Alternative Characteristics
0. Existing situation for comparison.
1 • Converts 4-way stop to 3-way stop.
Diveru traffic to Village Center Road.
Impacts Meadow Drive pedes[rian zone.
I
2• Combines ramp terminals into one intersection.
Reduces turning movement conflicts.
Increases intersection spacing.
3• New exit/entry ramps at VA shops.
Right turns only at EB exit to Vaii Road.
Operational analysis to be done without signals.
Federal access approval ro I-70 exists.
4• Relocates EB entry to South Froatage Road.
Simplifies operations at EB exit ramp.
Complicates directional signing to I-70 east.
Town of Vetl Page 72
Va➢ Transportallon Master Plan Chapter VI
Table 12 (con't)
Main Vail Incerchange Design Alternatives
Alternative Characteristics
5. Increases laneage at ezisting in[erchange.
Retains all existing traffic patterns.
6. Relocates EB and WB envies to Frontage Roads.
Simplifies individual intersection operations.
Complicates directional signing to I-70.
7. Provides new I-70 ceossing east of Main Vall
interchange.
Reduces traffic through interchange aeea.
8. Relocates east ramps ta exis[ing underpass east
of golf course.
Reduces traffic through interchange and 4-
way stop.
Town o( Yell Page 73
Vail Trensportetion Master Plan Chepter VI
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Town of Vail Page 74
Vail TranspoAetion Master Plan Chapier VI
It can be seen from Tabte 13 that Alternative 8, relocating the east ramps to the Booth Falis
underpass, would yield the best intersection operations given the appropriate traffic controi and
intersection improvements. Alternative 3 is significantly over capacity at Vail Road/north ramps
intersection without demand responsive control. In addition demand response control is required at
a total of three other intersections while Alternative 7 and 8 require demand responsive control at
only two intersections. While Alternative 7 results in significant overall improvements to traffic
operations, it is the least effective in elimina6ng congestion at the 4-way stop even under demand
responsive control.
In addition to traffic operations, right-of-way consideratioas, approvals required, physical and visual
impacts, and construction costs are also important. These aspects are summarized for each alternative
in Table 14. In addition, each aspect has been subjectively rank ordered by altemative, and rankings
have been summed for an overall ranking of each alternative for comparative planning purposes.
Table IS illustrates the results.
MAIN VAIL INTERCHANGE RECOMMENDATIONS/PRIORITIES
The following are recommendations regarding the Main Vail interchange to relieve traffic congestion
prioritized by short-term and long term actioas.
Short-Term
o As a first priority, construct aa I-70 underpass in the vicinity of Simba Run connecting the
North and South Frontage Roads.
o Conduct a coatrolled test in which the east Main Vail ramps would be closed and sign easterly
oriented traffic to use the East Vail interchange. Results of (his will indicate how well the
Long-range solution will work.
o Continue to manually control (Vail's preferred 4raffic conteol method) the 4-way stop
intersection during peak periods.
Lona-Term
o Relocate the east ramps to the Booth Falls underpass as shown in Figuee 16. The westbound
off-ramp/East Frontage Road intersection will require stop sign traffic control in all
directions. Keeping the east ramps at the Main Vail interchange open duriag non-peak
months may also be a possibility.
o Improve the frontage road be4ween Main Vaii and Booth Falls as necessary to accommodate
increase volumes and improve safety.
o Depress and modify ehe South Frontage Road in the vicinity of Vail Valley Drive and
manually control the intersection during peak hours. This is required because the existing
grades on Vail Valley Drive necessitate that the minor roadway have the right-of-way. This
greatly impacts the capacity of the major roadway and wili only worsen in the future.
Town of Vail Page 75
Vaii TranspoAetion Master Plan Chapter VI
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Town ot Vail Page 76
Vail TrenspoAatlon Mester Plan Chepter VI
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Town of Vail Page 77
Vail Transportelion Master Plen Chapter VI
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Town oT Vail Page 78
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/NORTH RAMPS
Exi in
Critical movement at this intersection is the left turn off of the ramp. Both A.M. and P.M. volumes
were evaluated and it was found that the A.M. peak hour was more critical. Unsignalized analysis
(next page) yield a LOS F with reserve capacity at 156. LOS thresholds are as follows:
> - 400 LOS A � <0.60
300 - 400 LOS B » 0.60 to 0.70
, 200 - 300 LOS C » 0.70 to 0.80
100 - 200 LOS D » 0.80 to 0.90
0 - 100 LOS E - 0.90 to 1 .00
< 0 LOS F » 1 .00
Assign V/C Ratio to Thresholds
1 vehicle of reserve capacity wouid be equivalent to 0.001 of V/C. So, 156 is 1 . 156 or 1 . 16
for left turn in A.M. peak hour.
Future - No Imorovements
Volumes were increased 1896 and analysis was redone
Reserve Capacity is 325
From Above, V/C = 1,325, say 133 A.M. Peak
Future - With Simba Run Underoass
Volumes were adjusted to reflect UP (page 4 for analysis)
Reserve Capacity is 209
From Above, V/C = 1 .�.09, say 1 .21 A.M. Peak
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/NORTH RAMPS
Future - Alternative 3 (Red Sandstone Partiai Interchanael and Undernass
This interchange alternative does not affect operations along the north side of the interchange.
the V/C is identical to the previous calculations
1 .21 A.M. Peak
Future - Alternative 7 (Vail Vallev Connection) and Undernass
This interchange alternative simplifies the north ramps intersection; only two movements would be
occurring - the left turn onto the WB on-ramp and the left turn off of the WB off-ramp. An
unsignalized LOS analysis was run (p.56) with a resulting reserve capacity of 45 vehicles for the left
turn off. From page 1 ,
V/C = 0.955 or 0.96 A.M. peak
Future - Alternative 8 (Booth Falls Ramosl and Undernass
North ramp operations would be divided in this alternative. The left turns onto WB on-ramp would
remain at the Main Vail interchange, but they would be the onlv movement along the north side of
the interchange and would be free flow. Hence, there is no longer an intersection at that locat➢on and
therefore no intersection LOS problems.
The left turns off of WB off-ramp would now take place near Booth Falls. An unsignalized LOS
analysis of A.M. peak volumes Yhere yielded a LOS F far lef¢ ¢uras off o£ YHe off-eamp. Theeefoee,
an all-way STOP analysis was done as follows:
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/NORTH RAMPS
Revise Volumes at Booth Falis Off-Ramp Intersection (Existing A.M. Peak)
uo. F�. Rd ,
NB and SB Aooroach Vofumes - 553
of�
c EB and SB Aooroach Volumes - 345 + 75 = 420
SO . Ir. �� ��
LOS C is 1 , 118 (assume V/C = 0.75)
Total Approach Volumes = 973
Multiply by 1 . 18 for Growth » 1 , 148
1 , 148/( 1 , 118/0.75) = 0.77
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/SOUTH FRONTAGE ROAD
(4-WAY STOP INTERSECTION)
This intersection is extremely close to the south ramps intersection and could be analyzed as a multi-
legged intersection as was done for the West Vail interchange. However, patterns at the south ramps
intersection are such that the largest movements are the thru movements along Vail Road and the
right turns off of and onto the ramps. Left turns onto and off of the ramps are relatively light, and
operations at this intersection will largely depend on operations at the 4-way. Therefore, the 4-way
STOP intersection is analyzed separately and is considered to be indicative of the entire area south
of the interchange.
Existine
Existing P.M. Peak Traffic (P.M. Peak Hour is Critical)
bf�,�
pr' The intersection is STOP sign con4rolled but is controlled
manually during peak periods which is essentially the same as
signal control. Therefore, since a oeak hour is being evaluat-
5^ � F`• � " ed, this intersection will be analyzed as traffic signal con-
� trolled.
�
Sum Critical Movements (4-Phase Signal)
Totai = 1 ,290
LOS E/F foe 4-Phase is 1 ,375
1 ,290/1 ,375 = 0.94 P.M. Peak DRC
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/SOUTH FRONTAGE ROAD
(4- WAY STOP INTERSECTION)
Future - No Imorovements
Volumes will increase 1896 and so will V/C ratio in this case.
V/C = 1 . 18 x 0.94 - 1 . 11 P.M. Peak DRC
Future - with Simba Run Underoass
Revised Volumes to Reflect Underpass (Existing P.M. Peak)
Sum critical moveme�ts similar to that done on page.8 (4-phase)
Multiply by 1 .18 for growth » 1 ,494
LOS E/F Threshold for 4-phase Signal is 1 ,375
1 ,494/1 ,375 = 1 .09
Future - Alternative 3 (Red Sandstone Partial Interchanael with Underoass
Revise Volumes (Existing P.M. Peak)
p� Q pr
.�
� �JM C,°.ITI^,A;. MO`✓E1�rN7'S
So . �• 2d �
�
��
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/SOUTH FRONTAGE ROAD
(4-WAY STOP INTERSECTION)
= 1 ,045
Multiply by 1 . 18 for Growth � 1 ,233
LOS E/F Threshold for 4-Phase Signal is 1 ,375
1 ,233/1 ,375 = 0.90
Future - Alternative 7 (Vail Vallev Connectionl with Underoacs
Revised Volumes (Existing P.M. Peak)
6{�O p,.�R'.^�
'��p SUM CRITICAL MOVEMENTS
� �
�, � . :
; �
Multiply by 1 .18 for Growth < 1 ,396
LOS E/F Threshold for 4 Phase is 1 ,375
1 ,396/ 1 ,375 = 1 .02
Future - Alteenative 8 (Booth Falls Ramns) and Underoa��
Revised Volumes (Existing P.M. Peak)
SUM CRITICAL MOVEMENTS
MAIN VAIL INTERCHANGE LOS ANALYSIS - VAIL ROAD/SOUTH FRONTAGE ROAD
(4-WAY STOP INTERSECTION) SOUTH FRONTAGE ROAD/RED SANDSTONE RAMPS
= 1 ,077
Multiply by 1 . 18 for Growth » 1 ,271
LOS E/F Threshold for 4-Phase is 1 ,375
1 ,271 / 1 ,375 = 0.92
Future - Alternative 3 (Red Sandstone Partial Interchaneel with Undernass
Analyze South Frontage Road/Ramps Intersection
(Existing P.M. Peak Volumes)
o�� �� �� All way STOP control was originally evaluated resulting in
LOS F. Therefore, DRC is evaluated (3-phase )
So. Fr. RJ
SUM CRITICAL MOVEMENTS
= 1 ,069
Multiply by 1 . 18 for growth � 1 ,261
LOS E/F Theeshold foe 3-Phase is 1 ,425
1 ,261 /1 ,425 = 0.89
MAIN VAIL INTERCHANGE LOS ANALYSIS - SOUTH FRONTAGE ROAD/VAIL VALLEY
DRIVEINTERSECTION
Several interchange alternatives have a direct impact on this intersection and it is therefore included
in the analysis.
Existine
$o . fr, Q� , Existing P.M. Peak Volumes
South frontage road approaches must stop, so conduct an
A unsignalized LOS analysis (p. 13).
� Lowest reserve capacity is 53 (WB approach) and using
� information derived on p. l , this corresponds to
� V/C � 1 ,053 say 1 .05
Future
Volumes are increased 1896 and unsignalized analysis is eerun (p. 14). Lowest reserve capacity is 239
(WB approach) and using information on p. l , V/C = 1 ,289 say 1 .24
Future with Underoass at Simba Run
This underpass would not affect the Vail Valley Drive intersection. » still L24
SUM CRITICAL MOVEMENTS
Multiply by 1 . 18 for Growth � 1 , 134
LOS E/F Threshold for 3-Phase is 1 ,425
1 , 134/1 ,425 = 0.80
MAIN VAIL INTERCHANGE LOS ANALYSIS - SOUTH FRONTAGE ROAD/VAIL VALLEY
DRIVEINTERSECTION
Future - Alternative 3 (Red Sandstone Ramos) with Underoass
The Red Sandstone ramps and UP do not affect this intersection. However, part of this interchange
al[ernative would include improving this intersection; i.e. lowering and/or lane additions. Volumes
shown on p. 12 still apply.
All way STOP analysis resulted in a LOS F still, so try DRC with increased iane geometry.
Lane Geometry
> a---
� �_
Phasine � �
�--_
F-- -a ' '- -
� � � � �
SUM CRITICAL MOVEMENTS
= 810
Multiply by 1 . 18 for growth » 956
LOS E/F Threshold is 1 ,425 of 3-Phase
9,560/1 ,425 = 0.67
MAIN V AIL INTERCHANGE LOS ANALYSIS SOUTH FRONTAGE ROAD/V AIL V ALLEY DRI V E
INTERSECTION
Future - Alternative 7 (Vail Vallev Connection) with Underoass
We now have a 4-legged intersection. Alt way STOP resulted in LOS F.
Existing P.M. Peak � I Assumed
Revised Volumes � �e � Geometry
----a �
� � �
SUM CRITICAL MOVEMENTS (4-PHASE SIGNAL)
= 811
Multiply x 1 .18 for growth » 957
LOS E/F Threshold is 1 ,375 for 4 Phases
957/1 ,375 = 0.70
Future - Alternative 8 (Booth Falls Ramosl with Underoass
All way STOP resulted in LOS F try DRC
Existing P.M. Peak � �— Assumed
Revised --� � Geometry
`l �
Phasine
I � �— �
'�' � v - - -
�
APPENDIX E
Main Vail Accident History
,�
�
MEMORANDUM
DEPARTMENT OFTRANSPORTATION
. 4207 East Arkansas Avenue _—_„_�=
Denver, Colorado 80222 ���_`_`
(303) 757-9011 �. �
� � 7� 7�/" � � � �
File No . 880 . 070 . 02 TRAFFIC
(ACCidents )
DATE : July 19 , 1994
TO : R . P . Moston '
FROM : Roger D . Gilpin//���/��'//(/ �, / "" ✓2�YVU
�
SUBJECT : Accident Experience - Two Locations in Region III
In response to Mr . Nall ' s request o£ June 16 , 1994 , we have
completed accident experience Por the three-year period January
1 , 1991 to January 1 , 1994 .
1 . SH 70 ( I 70 ). at the West Vail ( Chamonix Rd . ) Interchange
2 . SH 70 ( I 70 ) at the Main Vai1 (Vail Rd . ) Interchange
Location diagrams and accident summary sheets are being sent to
Mr . Nall .
RDG : jw ,�'L����4
��� f � ,� �a�
cc : J . Nall w/ encl ✓� � � � �
File ��
¢ ��,�. �
/
v
4�t�-�_��
STAFF TRAEFlC AltD SAFETY PROJECTS BRAHCF{
TYPICAL COLL' lSION DIAGRAM ' LEGEND
. FOR MOTOR VEH [ CLE TRAFFIC' ACCIDENTS
� ' • acetoarr �ocaTtoN
� —H ��. ��a.
Op=roadWay Off-roadway:{�ght) ON-roadway{left)
ACClOENT7YPES . SYMBOL_
HO - liead-on Ho —�=�—
RE - Fiear-end RE —♦--�-�•
SS - Sidewsipe-same��cfion SS ��
r--�... t-��- _
- SOj - Sideswipaoppostte d�ction SO � _
AT ° Approach tum AT ��—_ � - `
OT -: Overtaldng tum OT �
BS - Broadside BS '
T or AN
T � Trai�
(type indicated)
AN - Mirttal
PC - Patked car
p _ p�� . PC, Any ot the above
P or B as approp�iate
B - . Bicyde, Motorized.bicycle -
FO - Fi�cedobj�f- _ FO or0 � .
O - Othe� ob]ecf (tYPe indicated} �l�
OTR - Orertuming. OTR / � '�'
ONC- Oihernan-coll'ision ONC --�
(type indicated)
• ACCIOENT SEVEftfTY`
number of ��
pefsons kllled' —� 9 u_2 �uiai A�ciGei�i
O � Injury Accident
2. number af pecsons Injured
O• Property 0amage Only Accident
COLORADO DEPARTMENT OF TRANSPORTATION Fi�eu
�9 . o oz
SUMMARY OF MOTOR VEHICLE
TRAFFIC ACCIDENTS
Dale �7� ��i � %r/
Sheet / oi S
Description:
.��' 70 O �a� �/c r/'c�s� / �/ �.! /.� c�c/ .; r
Milepoint: j�'G . G3 t°:
Period: .�9i? �1l'! /, ��/� t9: ✓C/i'i�/l!�" �i /%/ �
I. NUMBER OF ACCIDENTS REPORTED V. LOCATION
One-car accidents � On-roadway accidents _�j (�
Two-car accidents Off-roadway accidents _�_�__
Three or more cars _�_
� Total _ � %
Total
VI. TYPES OF ACCIDENTS
II. SEVERITY Non-collision accidents
Fatal accidents U Overturning _�
Injury accidents � Other non-collision _�__
Property damage only _z�
Collision accidents
Total �"� Pedestrian __�_
Broadside 1._�
Persons killed O Head-on �__
Persons injured J�_ Rear-end �
Sideswipe S.D.
III. LIGHT Sideswipe O. D.
Daylight ��_ Approach turn _�
Dark, roadway not lighted Overtaking turn
Dark, roadway lighted �� Parked car
Train
IV. ADVERSE CONDITIONS Bicycle �
Weather Motorized Bicycle
Raining Domestic animal
Snowing � Wild animal
Road Fixed object �
Wet y Other object �_
Snowy �_
Icy ��
Total ��
COMMENTS;
.J�� ����-�� ..f �:a � � �/��G �!: . �- �� .t
i�-i✓��,..�
��--��i.-.
COLORADO DEPARTMENT OF TRANSPORTATION File NO. SBO . OJO . OZ
TRAFFIC ACCIDENT LOCATIONS
od1e July 12 , i94n
�, S.H. NO. 70 oisvia lII Pa"Otl January 1 , 1991 m January 1 , 19?4 sneei 5 oi 5
Descripuon
SH 70 ( I 70) south frontaoe road at the Intersection with Vail Rd .
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, COCORADO DEPARTMENT OFTRANSPORTATION Fi�eNO. gg0 . 070 . 02
TRAFFIC ACCIDENT LOCATIONS
Dala �Uly 12 . 1994
s.n. NO. �� Dislrict III aaaoe �anuary 1 , 1991 °i January 1 , 1994 snaa� 2 �� 5
DescripGOn
SH 70 ( I 70 ) at the Main Vail ( Vail Rd . ) Interchanqe
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COLORADO DEPARTMENT OF TRANSPORTATION Fi�e No. gg0 . 070 . 02
TRAFFIC ACCIDENT LOCATIONS
Dale �ul 12 . 1994
S.H. NO. 70 o�svm� III Pa^0� January 1 , 1991 °' January 1 , 1994 sneei 3 °� 5
� DescdpGon SH 70 ( I 70) Westbound Ramps at the Intersection with Vail Rd .
' Milepoint 176 . 03 10
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Cc^�LORADO DEPAR7MENT OF TRANSPORTATION File No. $g0 . 070 . 02
TRAFFIC ACCIDENT LOCATIONS
Daia �uly 12 > 1994 .
S.H. NO. �O o�sma jIi Pa^°� �anuary 1 , 1991 e January 1 , 1994 sneac 4 oi s
Descnpuon
SH JO ( I 70 ) Eastbound Ramps at the Intersection with Vail Rd .
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APPENDIX F
Understanding Rodel
UNDERSTANDING RODEL
Prepared for Greg Hall, P. E.
Town Engineer
Town of Vail, Colorado
by Leif Ourston, P. E.
Leif Ourston & Associates
Santa Barbara, California
August 25 , 1994
ABSTRACT
This report explains Rodel , a computer application that
predicts the traffic performance of modern roundabouts. Rodel
estimates delay, queue length , and capacity as functions of
roundabout geometry and flows . It was used to design Vail' s
proposed modern roundabout interchanges.
PHILOSOPHY BEHIND RODEL
Rodel was developed by Barry Crown of the Staffordshire County Council
in England . It applies research by the United Kingdom' s Transport
Research Laboratory, which licenses its use. Rodel is faster and easier to
use than a widely used program by the British Transport Research
Laboratory, ARCADY. Insofar as the two programs overlap, their output is
identical.
Rodel works like a spreadsheet in which the designer answers what-if
questions by changing one of the input parameters and running the program
again. Because Rodel is fast and easy to use , the designer is likely to
continue altering his design until a nearly optimal design is achieved.
Rodel permits the designer to select the confidence level of his estimates
of traffic performance. A confidence level of 50 percent is implicit in
other traffic performance programs, like ARCADY or TRANSYT. Rodel' s
author recommends using a confidence level of 85 to 95 percent. This
allows for inaccuracies in both the input design flows and the output
capacity estimate. Often a small increase in roundabout entry width or
flare length will greatly increase the probability that the roundabout will
perForm well at a high confidence level.
The Long Beach roundabout in California was designed using AK(;AUY
before Rod�l bec� rne available. ARCADY' s delay predictions are equal to
Understanding Rodel Z
those of Radel when Rodel is set to the 50-percent confidence level.
Delay predictions at the Long Beach roundabout (the busiest modern
American roundabout) compare with actual observed delays as follows:
AVERAGE STOPPED DELAY
(SECONDS PER VEHICLE)
PREDICTED OBSERVED
A. M. Peak Hour 2 . 2 2 . 7
P.M . Peak Hour 2 . 4 3 . 4
The difference between estimated and observed delay was 0. 5 second per
vehicle in the morning peak hour and 1 . 0 second per vehicle in the
afternoon peak hour. Because of the close correlation , it is believed that
Rodel' s estimates of delay may be close to the actual delay that will be
observed at modern roundabouts in Vail.
RESEARCH STUDIES
Capacity estimates of Rodel are based on research reported in Kimber, R. M ,
The Traffic Capacity of Roundabouts, TRRL Laboratory Report 942, 1980.
Regression equations were developed from data taken at 86 roundabouts
on public roads and 35 geometric variations on the TRRL ��uc�y �eack. The
capacity of each entry to a roundabout (Q�) was found to be a function of
one flow variable , circulating flow, and six geometric parameters . The
definitions of symbols are given below.
PARAMEfER YMB
Capacity = maximum
entering flow, pcu/h Qe
Circulating f�ow, pcu/h Q�
Entry width, m e
Approach half-width, m v
Length of flare, m I'
Inscribed circle diameter, m D
Entry angle, degrees �
� Entry radius, m r
Understanding Rodel 3
Capacity is estimated using the following six regression equations.
PARAMETER EQUATION
Sharpness of flare S = 1 . 6(e-v)/I'
Entry width parameter x2 = v+(e-v)/( 1 +2S)
Function of D tp = 1 +0. 5/( 1 +exp(( D-60)/ 10))
Adjustment factor, cap. curve k = 1 -0.00347 (� -30)-0. 978(( 1 /r)-0. 5)
Slope of capacity curve f� = 0.210tp( 1 +0.2xZ)
Y-intercept, pcu/min F = 303x2
The best predictive equations of capacity were:
Qe =k(F-f�Q�) when f�Q�<=F, and
Qe =0 when f�Q�>F.
Queues and delays are estimated by use of time-dependent queuing theory.
This is reported in Kimber, R . M . and Erica M . Hollis , Traffic Queues and
Delays at Road Junctions, TRRL Laboratory Report 909, 1979 . Queue
lengths are estimated in a series of small consecutive time intervals .
i raffic demand and capacity are assumed to vary from interval to interval.
INTERPRETING RODEL' S PRINTOUTS
Rodel prints out traffic performance given on a main screen, which has the
following twelve fields.
1 . TITLE
In the title section of the main screen are the date, written the British
way, day: month:year, the name of the roundabout, and the number of the
computer run . This last number corresponds to the number given in
subsequent statistics screens.
Understanding Rodel 4
2 . GEOMETRY
The user inputs seven geometric parameters. Distances are in meters.
E Entry width.
L' Length of flare between V and E.
V Upstream roadway width before flaring begins.
RAD Curb return radius.
PHI Angle between entering traffic and circulating traffic.
DIA Inscribed circle diameter of the roundabout.
GRAD SEP Grade separated, 0 or 1 ? The user inputs a one in this field if
the roundabout is very large, as at huge two-bridge British
grade separated roundabouts that run over or under the
freeway at some interchanges.
3 . TIME
The user inputs the following seven parameters which set the periods over
which traffic performance estimates are made. Times are in minutes.
TIME PERIOD The total period to be modeled.
TIME SLICE Equal pieces of the time period during which capacity and
demand flow remain constant. Capacity and flow may
change from slice to slice but not within each slice.
RESULTS PERIOD The period over which results are computed. If the time
period is 90 minutes and the results period is from
minute 15 to minute 75 , then results for the middfe 60
minutes are given.
TIME COST The value of driver's time in British pence per minute.
FLOW PERIOD The period over which the user inputs turning flows in
field 5 , explained below. If a 15 and 75 are given, the
user inputs flows for the middle 60 minutes.
' FLOW TYPE Flows of field 5 may be entered in passenger car units
( pcu ' s) or vehicles . A truck equals one vehicle or two
pcu's.
FLOW PEAK The peak hour being analyzed: a. m. , off peak, or p. m.
4. LEG NAME
The user inputs an abbreviation of the name of each leg of the roundabout.
The leg names are in the order of the direction that traffic flows around
the roundabout.
5 . PCU FACTOR
_ �' _ _ c _ � e _ �__ V _' .: aL..... F... .. ..L.�rJ� 'li� iir7orl hv +hn
i nis iS tne numoe� oi veniaes navii�y �i�uic u �au � vu � :� � ����� ..� � ���� �y �� ��
total number of vehicles.
Understanding Rodel 5
6. TURNWG FLOWS
For each leg, the user enters the number of vehicles exiting at the first
exit, the second exit, and so on up to the final flow, which is the number
of U-turns exiting at the entry leg.
7. FLOW FACTOR (FLOF)
The input flows are multiplied by this factor. With this factor the user
can perform a sensitivity analysis to see what would happen if flows
were to increase.
8. CONFIDENCE LEVEL (CL)
Queues and delays are predicted at the input confidence level . If 85 is
entered, we are 85 percent confident that the queues and delays will not
be greater than predicted.
9 . FLOW RATIOS
To allow for peaking of traffic within the peak period , the turning flows
are shaped into a flow profile. If the time period is 90 minutes and flow
times are set at minute numbefs 15 and 75 , then Rodel shapes the flow
profile into three rectangular steps: a beginning 15 minute step, a middle
60 minute step, and a final 15 minute step, the flow being constant within
each step. If the user inputs flow ra�io� of 0. 75 , 1 . 125 , �nd 0. 75 , then _
Rodel models the flow profile so that flows of the first and third step are
0. 75 times the average input flows, and flows of the middle step are
1 . 125 times the average input flows.
10. FLOW TIMES
The user inputs the flow times that are used with the flow ratios to
produce the flow profile from the turning flows.
11 . TRAFFIC PERFORMANCE
Rodel outputs the traffic performance of each leg in this field, as follows.
FLOW Entry flow, vehicles per results period.
CAPACITI( Capacity, vehicles per results period.
AVE DELAY Average delay, minutes per vehicle over results period.
MAX DELAY Maximum delay, minutes per vehicle over results period.
AVE QUEUE Average vehicles in queue over results period.
MAX QUEUE Maximum vehicles in queue over results period.
12 . TOTAL DELAYS AND COSTS
n � J..� . .t�.. .r.. aL. .. +..t.. l ..L.:..I.. .�l..ln I��� vc �vnr +ho rncu�tc nc �in� �t
RVUCI UULF./UW 111C lVlQl VGIIII.IC VG1ay iil � �vu � J vvc � �na. � �..au. w �+�. � .v�. . � �
gives the cost of this delay in �riti�h pounds stirling.
APPENDIX G
Roundabout Levels of Service
ROUNDABOUT LEVELS OF SERVICE os-2a-sa
Leif Ourston & Associates
Main Vail North
100% of Existing Flows
A.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPIIf FROM RODELOR ARCADY
FLOW veh/hr 307 41 S 564 1 6 1 ,305
AVE DELAY min/veh 0 . 05 0 . 02 0 .04 0 . 06
OIJfPUT
AVE DELAY sec/veh 3 . 0 1 . 2 2 . 4 3 . 6
DELAY sec/hr 921 502 1354 58 2 , 834
AVE DELAY, secNeh 2 .2
LEVELOFSERVICE A
P.M. PEAK HOUR
� WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPIIf FROM RODEL OR ARCADY
FLOW veh/hr 231 1078 313 17 1 , 639
AVE DELAY min/veh 0 . 04 0 . 02 0 . 05 0 .08
OIIfPUT
AVE DELAY sec/veh 2 . 4 1 . 2 3 . 0 4 . 8
DELAY sec/hr 554 1294 939 82 2 , 869
AVE DELAY, secNeh 1 . 8
LEVELOFSERVICE A
k#tYt#tY#Yk%i%l#x�t%#t#k#Ilk#Y%###�#��#�1YtY###%#x#k#�tYYA###�II##YYtYti#t##tkl#
# *
# 5 : 8 : 94 MAIN VAIL NORTH , 120 ' ROUNDABOUT 60 �
r �
#lfk#&1�YY#YY%##tX#k#######%Yt#%#IFYfiYY#%tz#IIkY%t##tT�##Y#YYYYt#t####t##Y#Xi%
$ # X
* E (m) 9 . 35 15 . 00 15. 00 8 . 53 7 . 80 � TIME PERIOD min 90 #
# L ' (m) 74 . 09 0 . 00 0 .00 39 . 19 23. 82 # TIME SLICE min IS *
� V (m) 6. 38 l5 . 00 15 . 00 6 . 93 3 . 65 $ RESULTS PERIOD min 15 75 #
� RAD (m) 9 . 95 15 . 00 15. 00 28 . 96 19 . 81 $ TIME COST pJe�in 1 . 79 �
� PHI (d) 40 . 00 0 . 00 0 . 00 18 . 00 29. 00 # FLOW PERIOD min 15 15 �
+ DIA (m ) 36 . 58 36 . 58 36 . 58 36 , 58 36 . 58 � FLOW TYPE pcu�veh VEH �
� GRAD SEP 0 0 0 0 0 # fLOW PEAK am/op/pm AM �
# # t
r��#sxxttt�zxxsx#r�zz�xtt#��xttxzs��#tttzxtttx��xx�zs�tztx�ttts�xxx�t�sxxxx��xax
* LEG NAME *PCU *FLOWS (lst exit 2nd etc . . . U)MFLOF$CL# FLOW RATIO �fLOW TIME�
s # t # x t x s
�N FA RD EB#1 .03� I6 259 0 0 0 �1 . 00$85$0 . 75 1 . 125 0 . 75$IS 45 75 �
*ON RAMP WB#1 .03� 0 0 0 0 0 $1 . 00#85#0 . 75 1 . 125 0 . 75�15 45 75 �
�VAIL RD NB#1 . 03# 0 1 124 249 0 $1 . 00#85$0 . 75 1 . 125 0 . 75#15 45 75 #
�OFFftAMP W6�1 . 03* 2 25 0 4I8 0 �1 . 00#85�0 . 75 1 . 125 0 . 15* IS 45 75 �
+SP C RD SB*1 . 03# 2 4 8 0 0 $1 . 00#85*0 . 75 1 . 125 0. 75*15 45 75 �
x a # : $ t t x
: � x x � x a �
**saxxxzsx:zzt��:�st:�x�z�x�:*t:a:x���xzx��xa�x*x:t::�sx::x�::�x:xx�t���z�*�:sxt
# r x
* FLOW veh 307 0 d18 564 16 $ TOTAL DELAYS $
� CAPACITY veh 1572 3261 4239 1973 1047 � *
* AVE DELAY mins 0 .05 0 . 00 0 . 02 0. 04 0 .06 � 1 hrs �
► MAX DELAY mins 0. 06 0. 00 0 . 02 0 . 06 0 . 08 $ *
* AVE AUEUE veh 0 0 0 0 0 � 4 pounds #
# MAX AUEUE veh 0 0 0 0 0 � $
� r x
x:x��xs�#rx�#t�#:��x:x�z::x:sx#t::#t:��z���#x:�sM:�xs::rx���xxx##z#xr�:ztz�zsr�
tt#tYit##�xt##t#1%�t#####�YYY####/t%#�#x##tYkit#t##t##Yt%#%#kkt#%t%##li##iYX####
t �
� 5 : 8: 94 MAIN VAIL NORTH , 120 ' AOUNDABOUT 61 �
x �
#:�t:*��*sx���x�:x�#::#:��xz��x:t���xzx:�+$t�rxxxr::��r�x:�:txxxx:�z:xxz�:��tx*�
# $ �
# E Im) 9 . 35 I5 .00 I5 . 00 8 . 53 1 . 80 # TIME PERIOD nin 90 *
# L ' (m) 74 . 09 0 . 00 0 . 00 39 . 19 23 . 82 � TIME SLICE min 15 �
# Y (m) 6 . 38 15 . OD 15 . 00 6 . 93 3 . 66 # RESULTS PEAIOD oin 15 75 �
# RAD (m) 9 . 95 15 . 00 I5 . 00 28 . 96 19 . 81 � TIME COST p/min 7 . 79 *
# PHI {d) 40 . 00 0 . 00 0 . 00 18 . 00 29 . 00 � FLOW PERIOD a�in 15 IS *
# DIA (m) 36 . 56 36 . 58 36 . 58 36 . 58 36 . SB $ FLON TYPE pcu/veh VEH $
# GRAD SEP 0 0 0 0 0 � FLOW PEAB am�opfpm PM �
# # �
x�x�xzttx�trxx�ts�xxxx*�tx*ittztt�xaxs�sts�t�t�zttxtftsr��x+s3xxt#txzs�x*�xztxx�
� LEG NAME #PCU ►FLONS (lst exit 2nd etc . . . U)�FLOf�CL� FLOW AATIO �FLOW TIME�
� � t z � x x t
�N FA RD EB�1 . 03# 5 201 0 1 0 $1 . 00#BS#0 . 75 1 . 125 0 . 75�15 45 75 �
#ON RAMP WB+1 .03# 0 0 6 0 0 #1 . 00*85#D . 75 1 . 125 0 . 75+15 45 75 $
�VAIL RD NB#1 . 03� 0 4 423 538 0 �1 . 00#BS#O. IS 1 . 125 0 . 75#15 45 75 *
#OfFRAMP W8�1 . 03# 1 64 0 215 0 �1 . 00�85�0 . 15 1 . 125 0 . 75�15 45 75 �
�SP C RD 56�1 . 03# 5 5 5 0 0 �1 . 00x85�0 .75 1 . 125 O . 15�15 45 75 *
: s � : z x t +
x � : x + ► � z
:'.#:S#Y#rS!;*;±�:ttyttXRxfYY*ixt*iYt#t#1%Y1%#1#t#il##ltYi#�.kY##Y#�IY%#####Y�Y#I#
x $ $
* FLOW veh 231 0 1078 313 t1 # TOTAL DELAYS �
� CNPACITY veh 1554 3685 4237 1469 798 $ *
# AUE DELAY mins 0 . 04 0 . 00 0 . 02 0. 05 0 .08 # 1 hrs #
# MAX DELAY mins 0 . 66 0 . 00 0 . 02 0 . 01 0 . 11 $ �
* AVE AUEUE veh 0 0 0 0 0 # 4 pounds *
� MAX AUEUE veh 0 0 0 0 0 # �
� e x
�:�x:ax��:r*�sx:�::at+::txt�t:x:rx�r::stxt::xxss��::x�z::x:x�zxx:Mx#���:x$�z��xa �
ROUNDABOUT LEVELS OF SERVICE oa-2a-sa
Leif Ourston & Associates
Main Vail South
100% of Existing Flows
A.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPIff FROM RODELOR ARCADY
FLOW veh/hr 823 284 603 321 630 2 , 661
AVE DELAY min/veh 0 .08 0 .07 0 . 05 0 . 05 0 .03
OtJfPUT
AVE DELAY sec/veh 4 . 8 4 . 2 3 . 0 3 . 0 1 . 8
DELAY sec/hr 3950 1193 1809 963 1 , 134 9 ,Og9
AVE DELAY, sec/veh 3 . 4
LEVELOFSERVICE A
P.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPIJf FROM RODEL OR ARCADY
FLOW vehlhr 465 216 919 484 1 ,247 3 ,331
AVE DELAY min/veh 0 .06 0 . 06 0 .06 0 . 06 0 . 04
OIIfPIIf
AVE DELAY sec/veh 3 . 6 3 . 6 3 . 6 3 . 6 2 . 4
DELAY sec/hr 1674 778 3308 1742 2 ,993 10 , 495
AVE DELAY, secNeh 3 . 2
LEVELOFSERVIC� A
X%liklYti*iY;Y%YY#%t##iklYl*Y34t#t####tYY%#k#Y#*#Y%#%t##X##t%�Xt##kk�#�######$#t
# #
+ 24 : 8 : 94 MAIN 4AIL SOUTH , 200 ' AOUNDABOUT 120 �
# t
t*a�z��t##����zt*t�szt�tt�tttrttx�xxxx�xxxxzx�xxtrx#z*x+zxxxtx�tx�xz�tttxtx�tx��
# r *
$ E (m) 8 . 01 7 . 21 8 . 67 8. 50 14 . 63 15 . 00 # TIME PERIOD min 90 $
+ L ' (m ) 7 . 81 85 . 23 9 . 23 6 . 39 64 . 78 0 . 00 # TIME SLICE min 15 *
� V (m) 5 . 27 6 . 32 7 . 92 7 . 37 6 . 40 15 . 00 $ RESULTS PERIOD min IS 15 $
# RAD (m) 42 . 67 23 . 32 21 . 34 19. 81 15 . 85 15. 00 � TIME COST p/min 7 . 79 �
� PHI (d) 14 . 0 39 . 0 14 . 5 22 . 0 17 . 0 0 . 0 # FLOW PEAIOD min 15 75 $
� DIA {m) 60 . 96 60 . 96 60. 96 60 . 96 68 . 26 60 . 96 # FLOW TYPE pcu�veh VEH �
$ GRAD SEP 0 0 0 0 0 0 $ FLOW PEAK am�op/pm AM �
y $ s
xsrxxs�xz::zz�:xx�xt�#xt��w::x:axxrx$��x��tz:xsxzx��xt�::xzzxr�zx�trrtxzxr�z�xe�
* LEG NAME #PCU *FLOWS ( Ist ezit 2nd etc. . . U)#FLOF�CL# FLOW RATIO �FLOW TIME�
s * � t s t � t
�VAIL AD SB*1 . 03* 0 232 140 339 26 0 #1 . 00�85*0 . 75 1 . 125 0. 75$IS 45 75 �
*OFFRAMP EB�1 . 03# D 48 204 0 2 D #1 .00$85�0 . 75 1 . 125 0 . 75�15 45 75 #
#S FR RD EB*L . 03� 156 263 67 54 0 0 #1 . 00#85#0 . 75 1 . 125 0 . 15�15 45 75 *
*VAIL RD NB#1 . 03* 53 35 100 0 99 0 $1 .00�85#0 . 75 1 . 125 0 . 75�15 45 75 �
#S FR AD WB*1 . 03# 42 211 0 178 127 0 *1 . 00�85�0 . 75 1 . 125 0. 75#15 45 75 �
�ON RAMP EB�1 . 03� 0 0 0 0 0 0 #1 .00�65�0 . 75 1 . 125 0 . 75�15 45 15 �
# � z z t a x x
xx:z::�zxx�ztxxx*�xxtxx�xx�xx:�rx�:z��xzx�srz�xxz:��z:��:x�xz:z�zxxxxx�xz��#zx�a
# � :
� fLaW veh 823 284 603 321 630 0 � TOTAL DELAYS $
� CAPACITY veh 1584 1125 1689 1501 2960 3372 $ �
# AVE DELAY mins 0 . 08 0. 07 D. OS 0 . 05 0 . 03 0 . 00 * 3 hrs �
# MAK DELAY mins 0 . 11 0 . 10 0 . 06 O . Q7 0 . 03 0 . 00 # #
� $ AVE AUEUE veh 1 0 1 0 0 0 � 12 paunds #
# MAX AUEUE veh 1 0 1 0 0 0 * �
# x *
*z�xssxxt���t���#z:�sxt�:::�x:xx�ztezx::x�zx���::x:::zxzxx�x::r�xt�xszr*�zx$sx��
Y%#%##Y##%tititYIi#%Y###Y%#tl�i�Yt#Y%X$##t####�####k#i�##t%#Y#Y##�##X#Y#k#k##Y�k
# �
* 24 : 8 : 94 MAIN VPII SOUTH, 200 ' ROUNDABOUT 122 $
t #
xtxxx�xtxxxzxxx**#�xx��xt�:�txz�z:rzs$x:zt:*:xxttztz�rtrx�:x:t�tztx�����xt��sxt�
# z #
$ E ( m) B . OI 7 . 21 8 . 67 8 . 50 14 . 63 15 . 00 � TIME PERIOD min 90 #
� L ' (m) 7 . 81 85. 23 9 . 23 6 . 39 64 . 78 0 . 00 � TIME SLICE min 15 �
� V (m ) 5 . 27 6 . 32 7 . 92 7 . 37 6 . 40 15 . 00 $ RESULTS PERIOD min 15 75 #
x RAD (m) 42 . 67 23 . 32 21 . 34 19 . 81 15. 85 15 . 00 � TIME COST p�min 7 . 79 *
# PHI (d) 14 , 0 39 . 0 14 . 5 22 . 0 17 . D 0 . 0 � FLOW PERIOD min 15 75 $
$ DIA (m) 60. 96 60 . 96 60. 96 60 . 96 68 .28 60. 96 � FLOW TYPE pcu/veh VEH �
# GRAD SEP 0 0 0 0 0 0 � FLOW PEAK am�opJpm PM #
� t �
�xxz�*�zx�zxz�:xx�x::��x�:x��:�txxtz:sxz�a�:���xx:x:xxzx::xx�:x:zxxx���tr:��x:x#
� LEG NAME #PCU +FLOWS ( lst exit 2nd etc . . . U)�FLOF$CL� FLOW RATIO *FLOW TIME#
� x x x r : � :
�VRIL RD SB*1 . 03� 0 126 75 189 24 0 �1 . 00#BS$0 .75 1 . 125 0 . 75$15 45 15 �
�OFFRAMP EB#1 . 03� 0 34 154 0 5 0 �1 . 00#85$D . 75 1 . 125 0 . 75�15 45 75 �
$S FR RD EB$1 .03# 127 372 174 145 0 0 �1 . 00+85#0 . 15 1 . 125 0. 15�15 45 75 #
*4AIL RD NB�1 . 03# 55 73 206 0 99 0 $1 . 00#85�0 .15 1 . 125 0 . 75M15 45 75 #
#S FR RD WB#1 .03# 111 605 0 289 1Q5 0 #1 . D0�85$0 . 75 1 . 125 0 .75+15 45 75 �
#ON ft4MP E8�1 . 03� 0 0 0 0 0 0 #1 . 00�85�0. 15 1 . 125 0 . 75� 15 45 15 �
x t t t x * z �
x�trx�x:tx�x����z*x�x�+zx:*:�::�:rtz:z#zx��tzxtx�:��x�#s:zt:�#zz�xaz�t�z�:r:�:�x
� : �
� FLOW veh 465 216 919 484 1247 0 # TOTAL DELAYS #
- # CAPACITY veh 1527 1266 1909 1423 2664 2611 # �
* AVE DELNY �ains 0 . 06 0 . 06 0 . 06 0 . 06 0. 04 0 . 00 # 3 hrs $
$ MAX DELAY mins 6 . 07 0 . 08 0 . 09 0 .09 0 .06 0 . 00 $ �
� AVE AUEUE veh 0 0 1 1 1 0 # 14 pounds $
# MA1( AUEUE veh 1 0 1 1 1 0 # �
$ : x
rz*r�:ttxzttx�tts:�zx�x:tx�t�xzx:xz$xt::x:xtxaxzxxx::x�xzxr:�x��x*trttrt#:stt�tx
ROUNDABOUT LEVELS OF SERVICE OB-24-94
Leif Ourston & Associates
Main Vail North
150% of Existing Flows
A.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG b LEG 6 ROUNDABOUT
INPLR FROM RODELOR ARCADY
FLOW veh/hr 461 627 846 23 9 ,957
AVE DELAY min/veh 0 . 07 0 .02 0 .06 0 . 08
QUfPUT
AVE DELAY sec/veh 4 . 2 1 . 2 3 . 6 4 . 8
DELAY sec/hr 1936 752 3046 110 . 5 , 845
AVE DELAY, secNeh 3 . 0
LEVELOFSERVICE A
P.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPLR FROM RODEL OR ARCADY
FLOW veh/hr 347 1617 469 25 2 ,458
AVE DELAY min/veh 0 . 07 0 . 02 0 . 1 1 0 .20
OUTPIff
AVE DELAY sec/veh 4 . 2 1 . 2 6 . 6 12 . 0
DELAY sec/hr 1457 1940 3095 300 6 , 793
AVE DELAY, secNeh 2 . 8
LEVEL OF SERVICE A
kYt#######I#Y%Y%X#%t##YkY#%##�I%�%�%##YtYRi�#k####Yk##1##1%%#t%#t#1#YYY%Y#t#####
Y #
# 24 : 8 : 94 MAIN 4NIL NORTH , 120 ' AOUNDABOUT 66 #
x �
:*��:x�zsx��::s�*:xx�xx����:x:��:�azt$�:�#xx�z�+��::zt�#t��z�z�::��r�����xs�z��s
� � �
$ E (m) 9 . 35 15 . 00 15 . 00 8 . 53 7 . 80 # TIME PERIOD min 90 �
# L ' �m ) 74 . 09 0 . 00 0 . 00 39 . 19 23 . 82 � TIME SLICE min IS �
# V (mJ 6 . 38 15 . 00 15 . 00 6 . 93 3 . 66 * RESULTS PERIOD min IS 75 �
# RAD (m ) 9 . 95 15 . 00 15 . 00 28 . 46 19 . 81 $ TIME COST pJmin 7 . 19 #
� PHI (d ) 40 . 00 0 . 00 0 . 00 18 . 00 29 .D0 � FLOW PERIOD min 15 15 �
$ DIA (m ) 36 . 56 36 . 58 36 . 58 36 . 58 36 . 58 $ fLOW TYPE pcufveh VEH *
� GRAD SEP 0 0 0 0 0 � FLOW PEAK am�op(pm AM #
� � x
x�r��x�$:�:�:�:z��$x��x:x::�x:�t::�t�zez�#:xx��ztt:zx�xr�x$��axz��:�:x�xs�:�r���
� LEG NAME #PCU *FLOWS ( lst exit 2nd etc. . . U)�FLOF#CL+ FLOW RATIO *FLOW TIME�
t x s � s z t x
#N FA RD EB*1 . 03# 16 259 0 0 0 �1 . 50�85�0 . 75 1 . 125 0 . 75#15 45 75 #
#ON RAMP W8�1 . 03* 0 0 0 0 0 �1 .50#85$0 . 75 1 . 125 0 . 75�15 45 75 �
�VAIL RD NB*1 . 03$ 0 1 124 249 0 $1 . 50$65$0 . 75 1 . 125 0 . 75#IS d5 15 $
$OfFRAMP NB�1 . 03# 2 25 0 478 0 $1 . 50$85#0 . 75 1 . 125 0 . 75�15 45 75 #
$SP C RD SB*1 . 03# 2 4 8 0 0 *1 . 50�85�0 . 15 1 . 125 0 .75�15 45 75 �
s x t t t t � t
r : z # � # x $
*x�zx��Mx*�x:xxz�s�:::xz�rxx��:r:�x��tt+�xxz�x�x��x�*z�tx�:xzxztzx#xxxzzxx:z::ar
� � *
* FLOW veh 461 0 627 846 23 # TOTAL DELAYS �
# CAPACITY veh 1286 2772 4239 1814 747 � *
� AVE DELAY mins O . D1 0 . 00 0 . 02 0. 06 0 . 08 # 2 hrs #
� MAl( DELAY mins 0 . 11 0 . 00 0 . 02 0 . 09 0 . 12 # �
* AVE 9UEUE veh 1 0 0 1 0 $ 8 pounds �
* MAX 9UEUE veh 1 0 0 1 0 � *
$ t t
st�t�s##xtx�M$##tts�#zx#�sxszsxx#sxzr*�r#��t�*t�rt�txxx#xt#xttxa�t$�tttt�t#t�t�
�tkt##Y#tYk##tkS#t#tY%kYk##tYt#Y#%X##SXf##t##%I#1##Y##k#�###�Y%%#%###�###1#Y#Y%
# �
* 24 : 8 : 94 MAIN VAIL NORTH , 120 ' RDUNDABOUT 61 $
r �
z:tx:�:���tzz��zxz�$x�tzxxxxxaz#x::z:x�M�t��::�zxxzzrxx:x:zxx#:$z��xzxax�rrzxtz�
x # *
* E (m ) 9 . 35 15 . 00 15. 00 8. 53 i . 80 � TIME PERIOD min 90 $
� L' (m) 74 . 09 0 . 00 0 . 00 39 . 19 23 . 82 ; TIME SLICE min 15 #
$ V (m) 6 . 38 15 . 00 15 . 00 6 . 93 3 . 66 $ ftESULTS PERIOD min 15 75 $
� RAD (m ) 9 . 95 15 . 00 15 . 00 28 . 96 19 . 81 � TIME COST pJmin 7 . 19 *
� PHI (d) 40 . 00 0 . 00 0 . 00 18 . 00 24 . 00 $ FLOW PERIOD min 15 75 #
$ DIA (e�) 36 . 58 36 . 58 36 . 58 36 .58 36 . 56 # FLOW TYPE pcu/veh 4EH *
$ GRAD 5EP 0 0 0 0 0 # FLOW PEAK amlop�pm PM �
# x �
tr�*rxxxax�xx��tst�#zxxxxts�:xz:zts�x���:x�rx::�srztzx�M�x�x*:xzsx::tt�z�x�xxx�t
* LEG NAME $PCU �fLOWS (ist eait 2nd eta . . U)zFLOF$CL# FLOW RATIO �FLOW TIME�
x x x # t t x t
�N Fft RD EB#1 . 03� 5 201 0 1 0 $ 1 . 50�85$0 . 75 1 . 125 0 . 75$15 45 75 �
*ON RAMP WB►1 .03� 0 0 0 0 0 #1 . 50#85$0 . 75 1 . 125 0 . 75� 15 45 75 #
#YAIL RD NB*1 . 03� 0 4 423 536 0 $1 . 50�85$0 . 75 1 . 125 0 . 75�15 45 75 *
*OFFRAMP W8�1 .03# 1 64 0 215 0 $1 . 50#85#0. 75 1 . 125 0 . 75*15 45 75 �
$SP C ftD 58�1 . 03$ 5 5 5 0 0 *1 . 50#85#0 . 15 1 . 125 0. 15�15 45 75 �
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# FLON veh 347 0 1617 469 25 # TOTAL DELAYS #
# CAPACITY veh 1258 3d08 4237 lOSB 313 � #
� AVE DELAY mins 0 . 07 0 .00 0 . 02 0 . 11 0 . 20 $ 2 hrs �
* MAX DELAY mins 0 . 09 D. 00 0 . 03 0 . 17 0 . 33 # #
% AVE AUEUE veh 0 0 1 1 D � 9 pounds �
# MAK AUEUE veh 0 0 1 1 0 $ *
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ROUNDABOUT LEVELS OF SERVICE oa-2a-sa
Leif Ourston & Associates
Mai� Vail South
150% of Existing Flows
A.M. PEAK HOUR
WFiOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPIJf FROM RODELOR ARCADY
FLOW veh/hr 1235 426 905 481 945 3 , 992
AVE DELAY min/veh 0 . 40 0 . 19 0 . 15 0 . 09 0 . 03
OUTPIJf
AVE DELAY sec/veh 24 . 0 11 .4 9 . 0 5 .4 1 . 8
DEIAY sec/hr 29640 4856 8145 2597 1 , 701 46 ,940
AVE DELAY, secNeh 11 . 8
LEVEL OF SERVICE B
P.M. PEAK HOUR
WHOLE
LEG 1 LEG 2 LEG 3 LEG 4 LEG 5 LEG 6 ROUNDABOUT
INPUTFROM RODELORARCADY
FLOW veh/hr 697 323 1379 725 1 , 870 4 ,994
AVE DELAY min/veh 0 . 09 0 . 09 0 .27 0 . 24 0 . 1 7
QUTPIIf
AVE DELAY sec/veh 5 . 4 5 . 4 16 .2 14 . 4 10 . 2
DELAY sec/hr 3764 1744 22340 10440 19 ,074 57 ,362
AVE DELAY, sec/veh 11 .5
LEVEL OF SERVICE B
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* E (m) 8 . 01 7 .21 8 . 61 B . 50 14 . 63 15. 00 � TIME PERIOD �in 90 *
# L ' (m) 7 .81 85 . 23 9 . 23 6 . 39 64 . 76 0 . 00 $ TIME SLICE min 15 �
* V (m) 5 . 27 6 . 32 1 . 92 7 . 37 6 . 40 I5 . 00 $ RESULTS PERIOD min 15 75 #
# RAD (a�) 42 . 67 23 . �2 ?1 .�4 19. 81 15 . 85 15. 00 � TIME COST p/min 7 . 79 *
# PNI (d) 14 . 0 39 . 0 14 . 5 22 . 0 17 . 0 0 . 0 � FLOW PEAIOD min 15 75 #
> DIA (m) 60 . 96 60 . 96 60 . 96 60 . 46 68 . 26 60 . 46 # FLOW TYPE pcu�veh YEH ►
$ GRAD SEP 0 0 0 0 0 0 + FLOW PEAK amlap�pm AM �
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$VAII RD SB�1 .03� 0 232 l40 339 26 0 #1 . 50#85#O . iS 1 . 125 0 . 75#15 45 75 �
#OFFRAMP EB�1 . 03# 0 48 204 0 2 0 +I . SD�85�0 . 75 1 . 125 0 . 75$15 45 IS �
�S FR RD EB$1 . 03# 156 263 67 54 0 0 $1 .50�85�0 . 75 1 . 125 0 . 75#15 45 75 �
#UAIL ftD NB*1 . 03# 53 35 100 0 99 0 +1 . 50�85�0. 75 1 . 125 0 .75�15 45 75 *
�S FR RD W8#1 . 03$ 42 217 0 178 127 0 $1 . 50*85�0 . 75 1 . 125 0 . 75*15 45 75 �
*ON RAMP E8�1 . 03� 0 0 0 D 0 0 x1 . 50�85�0 . 15 1 . 125 0 . 15�15 45 75 �
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# FLOW veh 1235 426 905 461 945 0 � TOTAL DELAYS �
# CNPACITY veh 1455 719 1365 1112 2791 2934 � �
$ AVE DELAY mins 0 . 40 0 . 19 0 . 15 0 . 09 0 . 03 0 . 00 � 13 hrs �
� MAK DELAY mins 0 . 80 0 . 33 0 . 25 0 . 13 0 . 04 0 . 00 � �
� AVE AUEUE veh 8 1 2 1 1 0 � 61 pounds �
# MAR AUEUE veh 15 2 3 1 1 0 � $
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� E (m) 8 . 01 7 . 21 8 . 67 8 . 50 14 . 63 15 . 00 � iIME PERIOD min 90 #
# L ' (m) 7 . 81 85 . 23 9 . 23 6. 39 64 . 78 0 . 00 � TIME SLICE min 15 *
� V (m) 5 . 27 6 . 32 7 . 92 7 . 37 6 . 40 15 . 00 # RESULTS PERIOD min 15 75 �
# RAD (m ) 42 . 67 23 . 32 21 . 34 19 . 81 15 . 85 15 . 00 x TIME COST p/min 7 . 79 �
# PHI (d) 14 . 0 39 . 0 14 . 5 22 . 0 17 . 0 0 . 0 # fLOW PERIOD min 15 75 $
� DIA (m ) 60. 96 b0 . 96 60. 96 60 . 96 b8 . 28 60 . 96 � FLOW TYPE pcu/veh 4EH �
# GRAD SEP 0 0 0 0 0 0 � FL�W PEAK am�op/pm PM $
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#VAIL RD SB#1 . 03� 0 128 15 189 24 0 �1 . 50#85$0 . 75 1 . 125 0 . 75*15 45 75 �
�OFFRAMP E8�1 . 03� 0 34 154 0 (5) 0 #1 . 50�85�0 . 75 1 . 125 0 . 75$15 45 75 +
*S FR RD EB#1 . 03+ 127 372 179 (145 0 0 #1 . 50#85�0. 75 1 . 125 0. 75�15 45 75 �
#VAIL RD NB�1 . 03# 55 73 206 % 0 99 0 #I . 50�85�0 , 75 1 . 125 O . 15#15 45 75 *
*S FR RD W8�1 . 03# 11I ;605` 0 289 105 0 $1 . 50#B5�0 JS 1 . 125 0 . 75�15 45 75 �
�ON RAMP EB�1 . 03# 0 0 D 0 0 0 �1 . 50$85$0 . 75 1 . 125 0 . 75�15 45 75 �
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,�u,; ' ' � FLON veh 697 323 1379 725 IBlO 0 # TOTAL DEIAYS �
* CAPACITY veh 1369 490 1694 1055 2354 1607 $ #
� A4E DELNY mins 0 . 09 0 . 09 D . 27 0 . 24 0 . 17 0 . 00 � 16 hrs #
� MAX DELAY �ins 0 . 13 0 . 13 0 . 53 0 . 44 0 .32 0 . 00 � �
* AVE AUEUE veh 1 1 6 3 5 0 # 75 pounds �
* MAX AUEUE veh 1 1 11 5 4 0 # �
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