HomeMy WebLinkAboutGATEWAY TO HARMONY ROAD PUD - PRELIMINARY - 1-88A - SUBMITTAL DOCUMENTS - ROUND 1 - TRAFFIC STUDY (2)•
HARMONY PLAZA
SITE ACCESS STUDY
FORT COLLINS, COLORADO
DECEMBER 1987
Prepared for:
McDonald's Corporation
5251 DTC Parkway, Suite 300
Englewood, CO 80111
Prepared by:
MATTHEW J. DELICH, P.E.
3413 Banyan Avenue
Loveland, Colorado 80538
Phone 303-669-2061
I V 0
E;<: E C LIT I V E S I t 1HA R'Y
Harmony Plaza is a. proposed development located at the
intersection of College Avenue and Harmony Road. This
traffic impact study involved the steps of trip generation,
trip distribution, trip assignment, capacity analysis,
tr•.aff i c signal t,,iarra.nt analysis, signal progression anal y=.i s,
and accident analysis.
This. study assessed the impacts of Harmony Plaza on the
short range (1? 5) and long range (2010) street system in the
vicinity of the proposed development. As a result of this
analysis, the fol l ot,ji ng is concluded-
- The development of Harmony Plaza. is feasible from a.
traffic engineering standpoint. At full development as
proposed, a.pprox imatel y 5500 trip end_. vii 1 1 be generated at
this site daily. Also considered in this analysis is the
property to the north ttihich is. expected to generate an
additional 3500 trip ends. per day.
- Ex i s.t i ng opera.t ion at the Col 1 ege/Harmony and;•:/
1
HarmonMason intersections are acceptable tali th ex i sting
geometrics.
- By 1'71'5, given fu 1 1 development of Phase I of Harmony
Plaza .and an increase in background traffic, the signalized
intersect ion of Col lege and Harmony t-,li 11 operate acceptably
with some geometric improvements.. The Harmony/Mason and
College/Kensington intersections. will operate acceptably t-ji th
signal control . l,.)i th stop sign control, the Mason Street
i n ter sec t i ons- should operate at acceptable levels of service
during peak hours..
- By 2010, the Col l ege: Harmomy intersection v, i 1 1
operate acceptably at the noon peak: and unacceptably in the
of ter•noon peak . However., the geome tr• i cs. sho(,an/recommended on
Harmony Road are not at its full six lane vji dth . The
unacceptable operation is likely to occur for only a short
time on an average day. It is question -able t;lhether the tlorst
case peak hour should be made acceptable. There is a. paint
of diminishing returns for the investment in the street. If
the fu I t six lane width of Harmony Road is. considered in this
intersection, acceptable operation during the afternoon peak
hour is attainable, t0i th stop sign control, the t°ta.son Street
intersections operate acceptably. t,:ii th signals at the
College/Kensington or Harmony/tlason intersections, acceptable
operation ix1i l l occur.
- Signals at the College/Kensington intersection can
fit into an existing progression band on College Avenue. The
s• i gnal does not reduce the bandt,,l i dth along College Avenue.
The bandwidth is governed by other signals along College
"venue .
- The proposed stop sign controlled limited turn
driveway accesses to both College and Harmony wi l 1 operate
acceptably. A right -turn auxiliary (deceleration) lane is
warranted at each. This. right -turn lane would remove
vehicles from the through traffic stream providing a. safer
condition. The following recommendations are made with
regard to these right-in/right-out accesses:
- The access. to Harmony Road is recommended since it
has a. positive effect on the operation at the
Harmony/Mason signalized intersection. It is also
possible to design an adequate right -turn
deceleration lane for this access.
- The access. to College Avenue is recommended if the
College/Kensington intersection is signalized, since
it has a positive effect on the operation at the
signalized intersection. This improved operation has
the additional positive effect of providing the
'
longest possible through bandwidth on College Avenue.
- Without a signal at the College/Kensington inter-
section, the effect of the right-in/right-out access
is minimal and, as such, no recommendation can be
made.
- With the recommended control geometries, the accident
rate should be at an acceptable level for typical urban
conditions.
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I. INTRODUCTION
IThis s i to access study addresses the capac i ty,
geometric, and control requirements at .and near a proposed
commercial development k:novin hereinafter as Harmony Plaza.
It is 1 oc.ated at the intersection of College Avenue and
Harmony Road in Fort Col 1 i ns, Colorado.
Cueing the course of the analysis., numerous contacts
'
t;.lere made i::ji th the project planning consultant (ZVFK) and the
Fort C:ol 1 i ns. Traffic Engineering Department. This study
gener•.al l y conforms to the format set forth in the Traffic
Impact Study Guidelines. The study involved the following
steps.
1
_ Collect ph>,s.ica.l, traffic and development data.
Perform trip generation, trip distribution, and trip
.a.ss. i gnme n t .
- Cie ter•mi ne peak hour. tra.ff i c uol umes .and dai 1 y tr•aff i c
volumes.
- Conduct ca.pa.c i ty and oper•at i onal level of s.ery ice
analyses. on key intersections and roadvla-ty sections.
'
Analyze signal t:-.:�.ar•r•ant=_. and signal progr•es.s.i on .
- Analyze potential changes in accidents and safety
cons.i der•.at i on=_..
- Perform tAii th/vii thou analyses. to evaluate the need
for selected accesses to this property.
I I . EXI STIPJG CONDITIONS
The location of Harmony Plaza is shot•.ln in Figure 1. it
is important that a. thorough under -standing of the existing
conditions be presented.
1 Land Use
1
Land uses in the area are
commercial. Commercial development
primarily e i ther• vacant or
and vacant land exists to
the east (across. College Avenue),
south (across.
Harmony
Road) , and k!,ies.t ( acro_s Mason
S t r e e t) of Harmony
Pl aza. A
intense 4-,iarehousing use and
vacant land are
to the north
of this site. Commercial uses
are proposed for
the current
vacant land north of the site.
Land in the area
is
essentially flat. The center
of Fort Col 1 i ns 1 i
es to the
'
north of Harmon Plaza.
Road=_
The primary streets. near Harmony Plaza are s.hot%in in
Fi qure 2. Harmony Road is south of Harmony Plaza. It is an
east-vies.t street designated as a major arterial on the Fort
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SITE LOCATION FIGURE
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Col 1 i ns Master Street Plan. It has recently been constructed
lxlest of College Avenue to a four lane cross section with
center turn 1 .ane _.. South of Harmony Plaza, the west approach
to the Col l egerHa.rmony intersection ha.s been 4,,ii dened to
pr•ov i de adequate geome tr i c=_. for the short range future. East
of the intersection, Harmony Road has a four lane urban cross
section. The expected _.peed limit will be 35 mph. Sight
distance is generally not a problem along Harmony Road.
Currently, in the immediate vicinity of Harmony Plaza.,
signals exist at College Avenue and Mason Street. A signal
at the Harmony/Mas-on i nter_ect i on has recentI y been
i n_.ta.l l ed, In the long range future, Harmony Road is
expec ted to be a. s i x 1 .ane =_.tree t accord ng to the For, t
Col 1 i ns t9aster• Street Plan. The nearest other s i final along
Harmony Road i =. at Lema-y Avenue to the east Cone mi 1e) .
College Avenue borders Harmony Plaza on the east. It is
a. nor th-sou th stree t des i gnated as a. maxi or ar• ter i al on the
Fort Col 1 i n Master StFee t Plan. In this. area., College
Avenue has. .a s. i x 1 a.ne cross sec t i on vj i th at cen ter turn 1 ane .
The north and south legs of the College./Harmony intersection
have been changed to prov i de add t i onal 1 a.ne=_. i n the
i n ter _.ec t i on itself. Most of th i s has been done k,,, i th respec t
to the Arbor Plaza development on the sou tht.-.jest corner. The
existing speed limit is 40 mph. Signals currently exist .a.t
the Col I ege/Harmony i n ter sec t i on adj acen t to th i s s i to and at
a. number of intersections north of the site. No signal
currently exists south of this site.
Mason Street has recently been constructed from the
Target Store to Harmony Road and through Arbor P1 aza to
C:ol 1 ecie Avenue. It is approximately 40 feet tali de north of
Harmony Road. It provides. one travel lane in each direction
.and a. center turn lane at appropriate 1 ocat i on•_.. South of
Harmony Read, 1lason Street is 50 feet t.�Ode and v)i11 be
striped to serve the land uses uai th i n Arbor Plaza. Mason
Street is designated as. a minor arterial on the Fort Collins
Plaster Street Plan. It serves as a recirculation street for
the properties t,ih i ch are along College Avenue.
Existing Traffic
Daily traffic flot..j is shovyn in Figure .3. These are
machine counted volumes. conducted by the Colorado Department
of Hi ght,,iays- i n 1 =': and by the C:i ty of Fort Col 1 i ns i n 15187.
Peak hour turning movements obtained in November, 1 =8? are
also =.ho(.:ln in F i qure 3. Raw traffic count data is provided
in Appendix A.
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NOON/PM
RECENT TRAFFIC COUNTS FIGURE 3
Existing Operation
'
Since much c �f this area
is developing, many of the
streets and land uses are
not completed. The only two
intersections which could
be evaluated are College/Harmony
and Harmony/Mason. These
intersections were evaluated as.
signal controlled intersections
with existing geome tr i cs
using the volumes shown in
Figure 3. The peak hour operation
is shown in Table 1. The
Appendix B. Appendix C describes
calculation forms are provided in
level of service for
signalized and unsignalized
intersections from the 1985
Hi ahwaL Capacity Manual.
During peak hours, delays are
minimal on all approaches
and the operation is considered to
be acceptable.
III. PROPOSED DEVELOPMENT
Harmony Plaza is a. proposed mixed use commercial
development located at the intersection of College Avenue and
Harmony Road in Fort Collins.
Figure 4 shows a schematic of
the site plan of Harmony Plaza
indicating the uses shown in
Table 3, Trip Generation. The
short range analysis t 1??5)
included fu 1 1 development with
a 3 percent per year increase
in existing traffic. The long
range analysis (2010) included
full site development with the
traffic volumes indicated in
the North Front Range Corridor
Study.
' Trip Generation
Trip generation is important in considering the impact
of a. development such as this upon the
existing and proposed
street system. A compilation of trip
generation information
was prepared by the Institute of Transportation
Engineers in
1? 6, updated in 1983, and was used to
project trips that.
'
would be generated by the proposed uses
at this site. Table
2 shows the expected trip generation on
a daily and peak hour
basis.
No adjustments were made fortransit
or r i deshar i ng.
Therefore, the trip generation can be
considered
conservatively high.
'
Trip Distribution
Two directional distributions of
the generated trips
were determined for Harmony Plaza. Distributions
from the
commercial uses used population as the
attraction variable in
the gravity model. Future year (1995
and 2010) data was
obtained from information supplied by
the Fort Col 1 i ns
Planning Department. For the short range
(1995) analysis,
•
Table 1
1937 Peak Hour Intersection Operation
Inter_.ection
College/Harmony
Harmon y/Mason
Land Use
McDonal J' _ - 3.5 KSF
Sit Down Restaurant -
8.0 K8F
i_-Store
Gas
Retail - 3.2 K'SF
Grease Monkey.
Total
Noon PM
8 (0.57) D (0.78)
A (0.16) A (0.25)
Table 2
Trip Generation
Daily
Noon
Peak
P.M.
Peak
Trips
Trips
Trips
Trips
Trips
in
out
in
out
2400
154
144
76
67
778
52
44
.37
12
1125
54
54
54
54
1064
4:3
43
58
58
200
10
10
10
10
5567
313
295
235
202
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HARMONY
C-STORE
GAS
FAST FOOD
RESTAURANT
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SITE PLAN SCHEMATIC FIGURE 4
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the distribution is. s.hovdn in Figure 5; and for the Iona range
,,2010) analysis., the distribution is. shown in Figure 6.
Several 1-Arid use generators such as shopping centers,
drive-in (f.a=.t food) r•e =.t.:_kur•a.n ts., service =_.tat i ons.,
convenience market.s., and other support services (banks, etc.)
capture trips from the normal traffic passing -by the site.
For many of these trips, the stop at the site is a secondary
part of a 1 i nk*ed tr• i p s.uch as from vlork to shopping center to
home. In all of these cases, the dr i vevia-y volumes at the
site are higher than the actual amount of traffic added to
the adjacent s-treet system, since some of the site generated
traffic vias. already counted in the adjacent_ street traffic.
A pass -by factor of 25':x tl,ias applied to the newly generated
trips..
The procedure used to account for both pass -by traffic
and primary destination traffic is as fol 1 ov!s:
- Estimate the trip generation rate as is currently done And
deter -mine the total number of trips forecast to occur•,
b._:ksed on the size of the development.
- Estimate the percentage of pass -by tripS, and split the
total number, of tr• i ps into ttllo components, one for pas.s-by
trips and one for new trips.
- Estimate the trip di =_-tr i but i ons. for the ta,,to individual
components. The d i =.tr- i bu t i on of pass -by trips must
reflect the predominant commuting directions on adjacent
And nearby r•oadv,;_:cy fa.c i 1 i t i es.. Most peak period pass -by
trips are an intermediate 1 i nk in a. vior•k: trip.
- Conduct tv,10 separate trip assignment=_., one for pass -by
trips. and one for nevi trips.. The distribution for pass -by
trips v.) i l 1 require that trips be subtracted from some
intersection approaches and added back in to others.
Typically, this to i 1 1 involve reducing through-roadviax
volumes. And i ncrea.si ng certain turning movements..
- Combine the assigned trips to yield the total link:
loadings, and proceed with capacity analysis as normally
done.
Traffic Projections
' Traffic projections, for the short range time period were
obtained by factoring the existing traffic by 103 percent per-
*
This pass -by factor v.!a.s obtained by averaging pass -by
' factors. from the fol l ov,ii ng sources:
1. Transportation Engineering Design Standards, City of
Lakeviood, June 1935.
L. Development and Appl i cation of Tr i G, Generation Rates,
FHI:OA/LISDOT, January 15'85.
3. "A t1e thodol oay for Consideration of Pass -by Trips in
Traffic Impact Anal;+_ -es for Shopping Centers," Smith, S.,
ITE Journal, August 1986, Pg. 37.
1
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HARMONY
SHORT RANGE TRIP DISTRIBUTION
Z5%
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SITE
HARMONY
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FIGURE 5
LONG RANGE TRIP DISTRIBUTION FIGURE 6
year to obtain the expected
traffic in 1995 given
an average
'
rate of land development in
is identified as background
the immediate area.
traffic which passes
This traffic
by the site
on both Col 1 ege and Harmony.
Figure 7 shows. the
expected
1955 daily traff i c considering
the site generated
traffic and
'
the background tra.ff i c . These
volumes are comparable
to
those indicated in the t-Jorth
Front Range Corridor
Study.
' For 20+ year projections (year 2010) , the usual source
for projections is the Traffic F1 ot,i Map as provided by the
City. Hoviever , the last Traffic F1 ov) Hap provides
projections for. only the - ear 2000. Therefore, an estimation
' t,,ias. made of traffic in this area. by the year 2010 using the
latest Traffic Fl ovi Map and the knovil edge of what has been
occurring and what is expected to occur in this area of Fort
' Col 1 i n=.. Information developed for the t1orth Front Range
Corridor Study via=. also u t i 1 i zed in these projections. These
daily projections are shot -in in Figure G.
ITrip Assignment
Trip assignment is hot.i the generated and distributed
' trips are expected to be loaded on the street system. The
assigned trips are the resultant of the trip distribution
process. Figure = shovis. the short range noon peak hour
' assignment and the afternoon peak hour _-s . i gnment of the
Harmony Plaza generated traffic plus background traffic.
Figure 10 shot,is the long range peak hour assignment of the
Harmony Plaza generated traffic plus background traffic.
These .a.=_si gnmen+.=_. assume access dr i vet -jays at locations
proposed by either the developer or site planner.
I=;i gnat 4X!arra.nts
' As a matter of policy, traffic signals are not installed
at any location unless t!,larrants are met according to the
Ptanual on Uniform Traffic Control Devices. Hot-iever, , it is
possible to determine v.1hether traffic signal tiarrants are
' likely to be met based upon estimated HGT and utilizing the
chart and/or peak: hour viarants shot. -,in in Appendix D. Using
the peak hour traffic volumes shot!,in in Figure 9, it is l i ke l y
that traffic signal warrants t.-ii 1 1 be met at the College/
t Kensington intersection. Traffic should be monitored to
determine vihen or if traffic signal viarrants are met. The
t�,larrant analysis assumes. full turns at the College./Kensington
t intersection. !,Ji thout a signal at this. intersection, left
turns_ from Kensington are at unacceptable operational levels
of service due to the high volumes on College Avenue.
KENSINGTON
3,000
/5, 000
HARMONY
1995 DAILY TRAFFIC
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23,000
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FIGURE 7
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2010 DAILY TRAFFIC FIGURE 8
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44/49 N 133//01 OHO
moo LEGEND tom
NOON/PM
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1995 PEAK HOUR TRAFFIC FIGURE 9
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1 FKENSINGTON 130///0
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HARMONY Z50/300
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LEGEND
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2010 PEAK HOUR TRAFFIC FIGURE 10
1
Signal Progression
Signal progression was evaluated prior- to intersection
operational analysis in order to determine 4-,lhether a. signal
at the C:ol 1 ege,."Kensington inter -section should even be
considered. The State Hi ghwa-ty Access Code states. that this
1
analysis is necessary for All future or proposed signal
Along a. state h i ght,tay. In this area., U.S. 287 is a Category
h i ght;-i-=_ty. The analysis. require=- that progression be
possible along U.S. 287 with a desirable bandii dth of 40
percent (minimum 30 percent). A speed of 45 mph or the
posted speed vlhere less than 45 mph should be used. The
analysis should include signals one mile north and south of
the evaluated signal location. The analyses included in this
report =_.hotj progression diagrams from Horsetooth to Harmony.
(one mile) And Drake to Harmony (ttao miles). Neither include
1
signals south of Harmony since the nearest anticipated signal
is tt,ao ml es to the south At Trilby Road. I.,Ihere the desirable
or minimum b-andtAii dth cannot be achieved with the existing
-i gnats, then the maximum bands,, i dth possible is. that governed
b;: the existing signals. Ulhen this occurs, the evaluation
can only compare the existing condition to that v1 i th the
1
proposed signal location.
The technique used in the signal progression Analysis
was a computer program called Signal Progression Analysis
(SPAW prepared by the University of Florida. Transportation
Research Center. Its main functions include:
Interactive entry of arterial system data.
Display a time location diagram vihich provides
graphical representation of the quality of arterial
progression.
- Printing of a time -space diagram to show the quality
of progression.
- Optimization of signal offsets for a.rteria.l pro-
gression.
The program inputs are:
- Inter -section location
- Cycle length
Phasing
Offsets
- Speed
Any or all of these inputs can be changed iteratively in
Achieving the optimal progression.
College Avenue data for existing =_-i gnal s to the north of
Harmony Road v)a.=- not available at the time of these analyses
due to break down of the'C:ity'=- signal computer. Historic
(1986) peak hour traffic counts were used to determine the
t
phasing necessary to accommodate the existing traffic. In
lieu of actual phasing and offset data, this is the most
reasonable means of determining the existing signal phasing.
The evaluation was made with and without a signal at
Kensington. The signal progression on College Avenue was
analyzed based upon the following criteria:
- Cycle length of 120-130 seconds (as determined by
1 =86 progression analyses for the City of Fort
Collins).
- Posted speed of 40 mph.
- Mainline (College Avenue) G/C Patio
Drake G/C = 0.46 Off Peak:, G/C = 0.55 PM Peak
Harvard G/C = 0.82 Off Peak, G/C = 0.82 PM Peak
Swallow G/C = 0.70 Off Peak, G/C = 0.75 PM Peak:
Foothills G/C = 0.65 Off Peak, G/C = 0.63 PM Peak
Monroe G/C = 0.67 Off Peak, G/C = 0.55 PM Peak:
1
Hor• se t oo t h G/C = 0.40 Off Peak, G/C = 0.47 PM Peak
Boardwalk G/C = 0.7? Off Peak, G/C = 0.7-' PM Peak
Troutman G/C = 0 .79 Off Peak, G/C = 0.82 PM Peak
Kensington G/C = 100 no signal, G/C: = 0.80 with
signal
Harmony G/C = 0.48 Off Peak, G/C = 0.56 FM Peak
1
- Green time on the cross street is greater than the
pedestrian crossing time of the mainline at 4 feet
per second.
1
- Achieve the largest bandwidth possible along College.
In accordance with the State Highway Access Code, the
posted speed of 40 mph was used. An off peak cycle length of
120 seconds and a PM cycle length of 130 seconds were used in
these analyses.
Based upon traffic count data, a balanced (equal)
bandwidth is required for the off peak signal progression.
Page 1 of Appendix E shows the one mile, off peak progression
analysis with no signal at Kensington. The through bandwidth
is 27 seconds in each direction or 22 percent. This is under
the minimum allowable bandwidth for a Category 3 Highway in
the State Highway Access Code. Page 2 in Appendix E shows.
the one mi 1 e, off peak progression analysis with a. signal at
Kensington. The through bandwidth is 27 seconds in each
direction or 22 percent. Therefore, there is no deteriora-
tion of the through bandwidths on C:ol l ge Avenue when a signal
is introduced at Kensington. Pages 3 and 4 in Appendix E
show that it is possible to maintain a 27 second bandwidth in
each direction all the way to Crake Road. This provides a 22
percent bandwidth in each direction with or without a signal
located at Kensington.
In the afternoon peak hour, traffic count data indicates
that the southbound bandwidth should be wider than the
northbound bandwidth using an approximate 55%/45% ratio.
Previous progression studies have indicated that a. 130 second
'
cycle length should be considered. Page 1 in Appendix F
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shov:3=_• the one mi 1 e, P1•1 peak progression analysis vai th no
i gna.l at Kensington. The through bandvii dths are 16 seconds.
12 percent) southbcFund and 13 seconds (10 percent)
northbound. These a.�.Yer•age under the minimum al 1 oviabl e
bandwidth for a Category 3 Hi ghvlay. Page t in Appendix F
=•hove=_• one mile, PM progression analysis vOth a signal at
Kensington. The through bandwidth in each direction is the
same as if there were no signal at Kensington. Therefore,
there is no deterioration of the through bandt.-ji dth=_. on
C:ol 1 ege Avenue when a si final is introduced at Kensi gnton .
Pages 3 and 4 in Appendix F show the bandui i dthe. possible for
the tvJo mi 1 e PM peak progressions both t&ii th and vii thout a
signal at Kensington. This analysis re -enforces the
conclusion that the siona.l at Kensington has little effect on
the progression on College Avenue.
Tt.-,io vjeeks after the progression studies s.hov.in in
Appendices E and F v.)ere completed, the phasing and offset
information t!,ias available from the City of Fort Col 1 ins. The
e::< i =.t i ng patterns viere run for the off peak (noon) and
afternoon peak using the same progression analysis pr•ogr•a.m.
Conversations v,l i th Fort C:ol l i n=. Traffic Staff indicated that
the actual speed on College Avenue was generally less than
the posted 40 mph. Therefore, progression runs v,lere
conducted at 40 mph, 35 mph, and 30 mph. The progression
run=. betvieen Drake and Harmony for the off peak are shown on
pages. 1, 2, and 3 of Appendix G and for the afternoon peaty:
are shown can page-_• 4, 5, and 6 of Appendix G. The
progression analyses. run in 1?35 did not include Drake Road.
This is the reason the bandv�i dth_. shop::an in Appendix G are
significantly` different than that shot!•in in the 1?36 runs.
Appendix H s.ho+:is the off peak (pages 1, 2, and 3) and
afternoon peak: (pa.ge_. 4, 5, and 6) progression runs using the
ex. i st i ng phasing t.,,li th .adiusted offsets. As t,,1i th the
progre=.=.i on runs shown in Appendices E and F, a. signal at
Kensington Drive has 1 i th e effect on the progression on
Col 1 ege Avenue .
The above progre_si on anal i`ses are presented to shovi
that signals can fit on College Avenue. Design progression
-an a.l ,,s.i =. mu=_.t be conducted on a. regul ar basi s refl e c t i ng
change in land use, speed, and other variables.
The location of a. signal approximately 500-600 feet from
a. major si final ized inter -section, sometimes referred to as a.
"slave 1 i gh t , " is. a. concept v)h i ch has. been recommended in the
"Access Control Demonstration Project" prepared for the
Colorado Depar+.men+. of Hi ghviays, District 6. It is. a method
of providing access. to corner properties located at the
intersections. of major a.r ter• i a.l streets. It has been
implemented in the City of La.kevlood. The Lakewood Traff i c
Engineering Department vlas contacted to gain some insight
v! i th regard to their experience v,li th this concept. The
fol Iov:1ing comments viere made:
8
I
The access, point proposed for signal ization must have
much lower traffic volumes when compared to the major street.
A "rule of thumb" ratio of greentime is 1/3 versus 2/3.
- The left -turn lane storage requirements on the major
street at the arterial./arterial intersection take precedence
over the location of a signal at the access_..
- The access signal should have as few phases as
pos.s i bl e . A two or three phase signal seems to work best. A
fu 1 l eight phase signal is unacceptable.
- At the intersec t i on of two ar• ter i al s_., it i
acceptable to introduce s. i finals. at the accesses on two legs,
but not on all four- legs.
I
t
The "slave light" concept has been implemented in
La.ketlood on tt,ao adjacent 1 eqs at the Wadswor t h/Jet,,le I 1
inter-sec tion. tJadsysor'th Boulevard is a. s.ix lane arterial
which is also State Hi ghviay 121 . Jev)e1 1 Avenue i s a. four
lane ar•ter i a.l . The Lakeviood Traffic Engineering Department
stated that these si finals have been per -forming
sat i s.factor• i 1 y, s.er•v i ng the adjacent 1 and uses and not
negat i ve 1 y impacting either Wadsworth Boulevard or Jewell
Avenue .
Th e Wa.dst:,,ior• t h./Jet:..)e 1 1 1 oc a. t i on wou l d be s. i m i l .ar• t o t h e
College/Harmony intersection in Fort Col 1 i ns.. Both College
Avenue and Ha.r•monx Road are major ar•ter i al s vii th projected
traffic volumes similar to that projected for Wadst�.iorth
Bou 1 eva.rd and Jek&ie 1 1 Avenue . The existing signal at the
Har-mony/Mason intersection (located 550 feet vies_.t of College
Avenue? and the proposed College/Kensington signal (located
530 feet north of Harmony Road) are on adjacent legs of a
major si gnat i zed inter -section. Based upon the pr•eceedi ng
progression analyses, the operational and geometric analyses
provided later in this report, and the acceptabi 1 i t.y of this
concept in the State of Colorado, it is recommended that the
"slave light" concept be considered at this location. Final
determination is subject to more refined "design level"
studies.
Operat i ons_. Anal vs. i s.
Ca.pac i ty anal ys.es_. were performed on k e x i nter•s.ect i on
within and adjacent to Harmony Plaza. The operations
anal >1s.es. were conducted and discussed below as indicated on
the site plan for the short range (1??5) analysis. This
includes. a signal at the College/Kensington intersection and
r i oht-i n/r• i ght-out on both College and Harmony. The long
range �2010) analysis discusses other options available, such
' as no signal at the College/Kensington intersection, since it
is at the long range level of traffic that geometric and
0
9
1 6 0
operat i onal r•equ i cement=_• t�,,i 1 1 be at the maximum. The
philosophy used here is. that, if the traffic operations work.
for the long range condi tion, i t can vlork for the short range
condition. Also, the evaluation of the proposed right-
in/right-out on Moth College and Harmony are provided in a
separate section of this report.
Using the traffic volumes shouin in Figure S' and the
existing geome t_r• i cs., the intersections operate in the short
range condition as indicated in Table 3. Calculation forms
for these Analyses are provided in Appendix I. The
College/Harmony intersection will operate at level of service
E during the afternoon peak hour with the existing
geometries. Increa.s.ing the geometry for specific movements
t&ii l 1 improve the operation of the intersection during the
afternoon peak hour. These geometric improvements. And
corresponding level of service are also indicated in Table 3.
Adding a second sou thbound left -turn lane and a i.-aes.tbound
right -turn lane i.:tou l d improve the after -noon peak hour
operation to level of service D (0 .80). This is marginally
unacceptable, but may be al 1 otA!ed since it is a temporary
1
short range condition. Adding an eastbound right -turn lane
to Harmony t!,ii th the Above improvements 4,,iould improve the
afternoon peak hour operation to level of service D (0.77).
This is very close to the existing afternoon peak hour
operation at this intersection.
At the Harmony..-,, Mason intersection, the existing tt.,jo
phase signal vl i 1 l operate acceptably, except that the left
i
turns may not alt--,1•a.y's clear in a given cycle. Introduction of
relatively short left -turn phases for both Harmony and Mason
t,,iill clear the left turns and still maintain acceptable
operation c ver-al 1 . At the College/Kensington inter -section, a.
tvio phase signal t,.ii 1 1 operate acceptably, except that the
left turns may not Always. clear on a given cycle.
Introduction of re 1 .a.t i ve 1 y short left -turn phases for both
College and Kensington t-di 1 1 clear the left turns and st i 1 1
maintain Acceptable operation overal 1 . The short range
geome tr i cs are s.hot.in in Figure 1 1 .
Using the traffic volumes shovin in Figure 10 and
recommended geometries., the intersections operate in the long
range condition as indicated in Table 4. Calculation forms
for. these analyses are provided in Appendix j. As signalized
intersections, the College/Harmony and Harmony./Mason
intersections oper•.ate Acceptably 1.ai th improved geometr i cs. and
s.i anal phase improvements. The recommended:Fr•equ i red long
range geome tr i cs are shovlri schematically in Figure 12.
1 At the College./Kensington intersection, a. number of
access options. exist. The "mouth College Properties Plan"
indicates that right-in/right-out/left-in access can/should
be provided at public street intersections t�,ih i ch are not
signalized. Critical to providing this is that the
1 10
Table 3
1??5 Peak Hour Intersection Operation
Intersection
Noon
FIM
Col 1 ege/Ha.rmon y:
1?87/1?81 Geometr i cs
C
(0.66)
E
(0.90)
2 BBLT
A
(0.52)
D
(0.60)
2 SBLT, 1 EBRT
A
(0.48)
D
(0.77)
College/Kensington
2 Phase
A
(0.35)
A
(0.44)
4 Phase
A
(0.50)
B
(0.5?)
Harmony/Mason
2 Phase
A
(0.
1 8)
A
(0.29)
4 Phase
A
(0.28)
A
(0.42)
Mason Kensington
RT Kensington
A
A
LT Kensington
A
A
LT Mason
A
A
Mason/Access.
RT/LT Access.
A
A
LT Mason
A
A
College Right Out
A
B
Harmony Right Out
A
A
I
1
1�
I
SHORT RANGE (1995) GEOMETRICS FIGURE 11
Table 4
2010 Peak Hour Intersection Operation
Inter -section
tJoon
PM
College/Harmony
B (0.58)
D (0.83)
College../Kensington
B (0.57)
C (0.66)
Harmon y: Mason
A (0.47)
C (0.76)
Mason./Kensington
FT Kensington
A
A
LT Kensington
A
C
LT Mason
A
A
RT/LT Access
A
C
LT Mason
A
A
College Right Out
B
C
Harmony Right Out
A
A
I
I
I LONG RANGE (2010) GEOMETRICS FIGURE 12
I
1
1
1
11
L�
I
I
geometrics can be accommodated in the space A-vai1able . The
left -turn lane requirements at the major intersection, in
this case , the Col 1 ege: 'H•a.r•mony i n ter•=_.ec t i on , mu=_.t be
satisfied first. The second option available is signal iza-
tion of this. intersection.
The southbound College Avenue left -turn lane
requirements at Harmony Road are 430-570 feet (Appendix K) .
In order to provide any median break at Kensington, a double
loft -turn lane totalling 450 feet is possible. This is
;,,l i th i n the range indicated above. The storage requirements
for the left -in on Col 1 ege Avenue -at Kensington is. a. function
of the turning volume and the opposing traffic on southbound
College. Since Col 1 ege Avenue doe_/t&ii 1 1 have signal
progression, the analysis of the operation and geometr• i cs.
should consider- this. If it is assumed that 60 percent of
the opposing traffic (=_.outhbound) on Col 1 ege occur•s in
platoons., and the left -turning traffic arrives. si m i 1 .a.r• 1 y,
then a. situation exists that a portion of the time no left -
turns. are possible due to the arrival of a. southbound
platoon and a portion of the time loft turns are possible
related to the gaps. available in the opposing traffic. Using
a storage requirement of tvio vehicles (45 feet) during the
time when no turns are possible and applying the Har•me 1 i nk
Curves (Appendix L) to the randon turns (100 feet for the
afternoon peak traffic'), .a. total of 145 feet of northbound
left -turn lane is required at Kensington. This length can be
accommodated in the space available given the aforementioned
left -turn requirements at Harmony- Road. Figure 13-A shoi.�,,s a
design for the r ight-in/,r•ight-out.,`left-in movements. at the
Coll ege/Ken=_•i ngton intersection.
With =_. i gnat i zat i on at the Col 1 ege/Ken _• i ngton
intersection, georr,etrics and operation of the signal itself
must be considered. The southbound left -turn requirement=_. on
College Avenue at Harmony Road indicated above remain the
SFkme . The ay.=-k i 1 a.bl e 450 feet falls within the acceptable
range. With a signal at the Colleae`/Kensington intersection,
the length of a northbound left -turn lane is 140-180 feet as
determined from the nomograph shoe.,,in in Appendix K. This
length (use 160 feet) can also fit into the space available.
F i gur•e 1 3-B =.hok:,l a de=_ i gn for a. __• i gnat i zed C:ol 1 ege/
Kens-ington inters-ection. From an operations. point of view,
acceptable level of ser 'j i ce Moon -B, PM - C) is attained
v)i th a. four phase si gna.l . This, of course, assumes that
Kensington t&ii l l continue on the east side of College. The
analyses hot•�ed that signal �.i i th a 60:'20 phase
progress -ion r_�n a.nal _ �. t �. �.i 1 F
sp 1 i t has no effect on the bandt,li dth on College Avenue.
Actually, the College Avenue red phase can be increased to as
much as 35 percent and st i 1 1 have no effect on the College
Avenue bandi.,O dth . This 35 percent v)ou 1 d allow for a left -
turn phase on College, a. loft -turn phase on Kensington, and a
through/right phase on Ken=_• i ngton . While not necessary to
achieve acceptable operation at the College/Kensington
I
11
J
RIGHT-IN/RIGHT-OUT
HARMONY
W
a
W
O
COLLEGE AVENUE GEOMETRICS
WITH RIGHT -IN / RIGHT -OUT /
LEFT -IN ACCESS AT KENSINGTON
FIGURE 13 - A
J
RIGHT-IN/RIGHT-OUT
HARMONY
COLLEGE AVENUE GEOMETRICS
WITH SIGNAL AT KENSINGTON
FIGURE 13-B
t
1
1
1
intersection, consideration should be given to providing an
e:.-ec 1 u=_• i ve _•ou thbound right -turn lane on College approaching
Kensington. The turnino volume exceeds the viarrant for this
lane in the State Hi ghv,�ay Access Code. This lane wi 1 1 remove
right -turning vehicles from the through traffic lane
pr•ov i Ji rig a. much safer si tuat ion, i ncrea_•ed street ca.pac i ty,
and improved si to access..
At the Harmony/Mason s i final i zed i n ter•sec t i on , four• phase
oper•at i on vi i l l -assure tl,.a. t the con f 1 i c t i no 1 of t-turn
movements. on Moth Ha.=_•on and Harmony clear in a given cycle.
Given the volumes anticipated at thi=_. intersection, 45-50
percent of the cycle can be devoted to Harmony Road through
green. Operation at this intersection is expected to be
.acceptable.
A r i oht-i n./'r i ght-out access has been proposed on Col 1 ecie
Avenue, approximately 270 feet north of centerline of
Harmony, and on Harmony Road, approximately 320 feet west of
the centerline of College. Both of these accesses require
r• i ght-turn deceleration 1 tines in order to a.=_-=_•ur•e safe,
efficient operation. The College Avenue right -in,. -right -out
can be designed to al 1 ot,,i a 15 mph turn. If this is done, a.
deceleration length of 295 feet is required according to the
State Highway Access Code. This length «i11 extend the
deceleration lane through the Kensington intersection. It
is, therefore, recommended that the deco 1 er•at i on lane for- the
right-in./right-out access be continuous from Kensington to
the south. This type of con t i r+.uou=_• right -turn lane is common
on major arterials t:a i th the combination of high through
'.Yol ume= and high r• i qht-turning volumes. Since the _•outhbound
right -turn lane at the College/ oHarmony intersection i
recommended as shotin in Figure 12, the right -turn lane should
be continuous to Ha.r•mony Road.
If the Ha.r•mon>- Road r• i gh t- i n:. r• i gh t-out access i
de=_• i fined to al 1 ot,i a. 15 mph turn, a deceleration lane length
of 2,35 feet is. required according to the State H i ghtilay Access.
Code. Hoviever, , Harmony Road, v.!e=•t of College Avenue is not
State Hi ghvta.y and its location vii th respect to the College/
Harmony signal could allow some flexibility vaith repect to
its design. According to A Policy can Geometric Cie=_.iqn of
Highv.ia;•:._. and Streets, AASHTO, 1?84, pg. 874,
"The length of the au•r, i 1 i ary lanes for turning
vehicle_consists. of three components . (1)
2) age length, deceleration 1 eng th _, ( storage g , and
', 3) entering taper. Cues i rabl y, the total length
of the Aux i 1 i a.ry 1 ane should be the sum of the
length for these three components. Common
practice, however, is to accept a. moderate amount
of deceleration vai th i n the through lanes and to
consider the taper as a part of the deceleration
length. I:�•lhere intersections occur as frequently
1 0 0
Ci
as four per mi 1 e, it is customary to forego most
of the deceleration length and to provide only
the storage length plus taper . "
According to the deceleration distance nomograph, from
AASHTO, Pg. 36 and shown in Appendix M, a passenger vehicle
can comfortably brake from 35 mph to 15 mph in 180 feet. It
is, therefore, recommended that a right -turn lane/taper
combination total 1 i ng 200 feet should be provided on Harmony
Road approaching this access. This. wi 1 1 remove decelerating
vehicles from the through traffic lane on Harmony Road,
providing safe, efficient operation. This will also provide
a "pedestrian bulb" at the Col 1 ege/Ha.rmony intersection which
will shorten the walk time across Harmony Road. The
"pedestrian bulb" would also provide better lane alignment
for vehicles westbound on Harmony Road. A right -turn
acceleration lane is not recommended at this. access.
Both
of the right-in/right-out accesses Arai 1 1 be
'
evaluated
in a "wi th/wi thout" analysis in
Chapter IV. The
analyses
provided above show the access as
proposed by the
developer
of the property.
The
two intersections to Mason (the Mason/Kensington
intersection
and a. driveway access located
280 feet north of
Harmony)
wi 1 1 operate acceptably with stop
sign control.
Accident
Analysis
The
recommended control devices and geomet_rics
should
minimize
vehicular conflicts and maximize
vehicle separation.
Therefore,
the accident rate should be at
its minimum for a
'
typical urban
condition.
IIV. ACCESS ANALYSIS
If a. development plan proposes private driveway accesses
to arterial streets, the City of Fort C:ol 1 i ns requires. a
"with and without" analysis. The purpose of this analysis is
to show the change of operation to nearby intersections and
streets both with the proposed access and without the
proposed access.. The Harmony Plaza site plan proposes two
driveway accesses to arterial streets.. These are a. right-inr`
right -out access to College and a right-in/right-out access.
to Harmony Road. The earlier analyses in Chapter III show
the expected traffic volumes and operation with these two
right-in/right-out accesses. The long range peak hour
traffic volumes are shown in Figure 10 and the long range
peak hour operation at intersections is shown in Table 4.
Figure 14 s.hows. the long range peak: hour traffic volumes
'
without the two right-in/right-out accesses. Elimination of
1 13
0
N
�o
MN
O�
O
/5//5
35/40
N
Cr O
O�
1
80/SO
/00//ZO
41001500
/80/ 05 0 —1
L 2/S/ZO5
405/94,i
1001160
I I F
p00
NON
�O(Zj
KENSINGTON
HARMONY
2010 PEAK HOUR TRAFFIC
NO RIGHT-IN/RIGHT-OUT
ON COLLEGE OR HARMONY
NP N
0
m M lln L 130///0
Alom'
/55//35
/30//l0 F
/VONI -
/55//35 o 4
COS
N
050 /300
3001400
Z00//l00
L350/4S0
3101760
05 0/450
I I
O
0
pN0
O
N
Q
N
FIGURE 14
either acce=-=-• 3.s F = _ h•-= the mc�.�t Impact on the adjacent inter-
section, that is, the College Avenue access is related to the
College/Kensington intersection and the Harmony Road access
is related to the Harmony/Hason inter -section. Volumes at the
Col 1 ege/Harmony intersection are not 1 i kel y to vary much with
or i.,,ii thout the r i ght-i n/r— i ght-out accesses.
Table S shot,is the long range peak: hour operation at the
key intersection_. wi thout the tt%lo right-in:`r•ight-out
accesses. Calculation forms for these analyses are provided
in Appendix N. I t can be seen that the oper•at ion at both the
College/Kensington and Harmony/Mason intersections
deteriorates from that reflected in Table 4. More
significant than the deterioration in operation is the
additional time of the c:.cl e that must be devoted to the non -
through movements of the arterial streets. The shortening of
'
the through green phase at each intersection can begin to
affect the main street progression.
If the Col 1 ege/Kensington inter -section is not
si gna.l i zed, the movements are reduced to r• i ght-i n.rr i ght-out;
left -in. Fro:)iding the additional right-in/right-out access•
south of f:en_•i ngton tali l l increase the number of through
vehicles can College Avenue. No right-in/right-out access
increases• the number of southbound College right -turns at
Kensington. These right turns slightly reduce the number of
vehicles in the right hand through lane. The effect on
operation will be minimal.
Eased upon the analyses reflected in this report, the
fol 1 ovli ng recommendations are made with regard to the right-
in/right-out accesses:
- The access. to Harmony Road is recommended since it
has a positive effect on the operation at the Harmony/Mason
signalized intersection. It is also possible to design an
1
adequate right -turn deceleration lane for this access.
- The access to College Avenue is recommended if the
College/Kensington intersection is signalized, since it has a
positive effect on the oper.at i on at the signalized inter-
section. This improved operation ha.=_• the additional positive
effect of providing the longest possible through bandwidth on
'
Col 1 ege Avenue.
- l.flthout a ._ i gnal at the College/Kensington inter-
section, the effect of the right-in:/right-out access is
minimal and, as such, no recommendation can be made.
I V . CONCLUS I OHS
' This study assessed the impacts. of Harmony Plaza on the
short range (1 995) and long range (2010) street system in the
1 14
Table 5
2010 Peal! Hour Intersection Operation
with no Right-in/Right-out
on College
and Harmony
Intersection
Noon
P1.1
Col leae/Harmonx
8 (0.58)
D {0.83)
College/Kensington
6 (0.63)
C (0.6?)
Harmony/Mason
A (0.50)
D (0.78)
Mason: Kensington
RT Kensington
A
A
LT Kensington
A
C
LT Mason
A
A
Mason/Access
RT/LT Access
8
C
LT Mason
A
A
1
1
1
1
1
vicinity of the proposed development. As a re=u1t of t h i cS
.analysis, the following is concluded:
- The deve 1 opmen t of Harmony Plaza. is feasible from .a.
traffic engineering standpoint. At full development as
proposed, approximately 5500 trip ends vii 1 1 be generated at
this site da.i l y. Also considered in this analysis is the
proper ty to the nor th s,.ih i ch i s. expec ted to generate an
additional 3500 trip ends per day.
- Existing operation at the College/Harmony and
Harmony,1-1ason i n ter•sec t i ons are accep tabl e wi th ex i s.t i ng
geome tr• i cs..
- By 1 -'-'5, given full development of Phase I of Harmony
Plata and an increase in background traffic, the signalized
intersection of College and Harmony i;ii 1 1 operate acceptably
bJi th some geometric improvements. The Harmony/Mason and
Col l ege/Kens i ngton i ntersec t i ons. vii 1 1 operate a.ccep ta.bl y wi th
signal control. With stop sign control, the Mason Street
intersections should operate at acceptable levels of service
during pea.k: hours.
- By 2010, the Co] 1 ege,/Harrnon>' i nter•s.ec t i on wi 1 1
operate acceptabl--,� at the noon peak and unacceptably in the
-after-noon peak. Hoi;.lever, , the geome tr• i c=_• shouin/recommended on
Harmony Road are not at i t=_. ful 1 six lane t,,O dth . The
un.a•ccepta.bl e operation is 1 i kel y to occur- for only a short
time on an average day. It is questionable t..lhe ther the vjor•st
case peak hour should be made acceptable. There is a point
of diminishing returns for the investment in the street. if
the full six lane i„ii dth of Harmony Road is considered in this
intersection, acceptable operation during the afternoon peak
hour is attainable. With stop sign control, the Mason Street
intersections uli l 1 operate acceptably. (,Ji th signals at the
College/Kensington or Harmonx/1-1ason intersections., acceptable
operation t.-a i 1 1 occur.
- Sicinals at the College/Kensington intersection can
fit into an existing progression band on College Avenue. The
signal doe_. not reduce the bandwidth along College Avenue.
The bandk&li d+_h is governed by other signals along College
Avenue.
- The proposed stop sign controlled limited turn
dr i vev.ay accesses to both Col 1 ege and Harmony jai 1 1 operate
acceptably. A right -turn auxiliary (deceleration) lane is
warranted at each. This. right -turn lane t,iou 1 d remove
vehicles. from the through traffic stream providing a safer
condition. The fol 1 ok;.)i ng recommendet i ons are made t,.ii th
regard to these right-in/right-out accesses-
- The access_. to Harmony Road is recommended since it
has a positive effect on the operation at the
15
HarmanxrHascan signalized intersection. It is also
possible to design an adequate right -turn
deceleration lane for this access.
The access to College Avenue is recommended if the
Col lege/Kensington intersection is signalized, since
it has a. positive effect on the operation at the
signalized intersection. This improved operation has.
the additional positive effect of providing the
longest possible through bandwidth on College Avenue.
Without a. signal at the College/Kensington inter-
section, the effect of the right-in/right-out access.
is minimal and, as such, no recommendation can be
made.
- With the recommended control geometric=.} the accident
rate should be at an acceptable level for typical urban
condi t ions.
16