HomeMy WebLinkAbout04 - Traffic Impact Study - Harvest Creek Ph 8-11 Marvin & Associates
Traffic, Transportation, & Civil Engineers
Homelands Development Co.
Walt Wolf
11258 Cottonwood Road
Bozeman, MT 59718 March 15, 2004
Re: Harvest Creek Subdivision
Phases 8, 9, 10 & 11 T.I.S. Update
Dear Walt:
This letter serves as an update to the Traffic Impact Study (TIS) for Harvest Creek West
prepared by Marvin & Associates in June 2000. Updated information in this letter and
attachments is provided for phases 8, 9, 10 and 11 of the Harvest Creek Subdivision
development, with phases 1 thru 7 already having been completed. It is our
understanding that the City of Bozeman will not approve the development of Phases 8
through 11 until planned street improvements on Durston Road have been completed.
The purpose of this update is to determine what, if any, impacts would be placed on
Durston Road if the street improvements were not completed prior to development of
housing units in the new phases.
Current Traffic Volumes
New peak hour turning movement traffic counts were taken at the intersection of Durston
Road and Oak Street with N.19th Avenue on March 8, 2004 and February 3, 2004,
respectively. Data from the turning movement counts was used in combination with
automatic recording count data collected along Durston Road, east of N. 19"', in July
2003, as part of a separate project, to recalculate current average daily traffic (ADT)
volumes on the surrounding street system. Figure 1 illustrates the existing ADTs, as well
as p.m. peals turning movement volumes for the intersections of Oak Street and Durston
Road with N. 19"' Avenue.
The most substantial differences in ADT were found aloe Oak Street and on 19t1'
Avenue, north of Oak. Year 2004 ADT on Oak, west of 19", has increased by 250%,
while along the section of Oak east of 19th, ADT has increased by only 47%. The level
of increase on 19th Avenue, north of Oak, is almost twice the increase of that on the south
side, at 22%. Differences in ADT along Durston Road were also substantial, with a 20%
increase west of 19"' and a 7% decrease to the east. The ADT increase on 19t" Avenue,
south of Durston, was only 5%, in comparison to the 22% increase north of Oak.
Considering .the fact that Oak Street, west of 19th, only serves to access residential
developments south of Oak (including the Harvest subdivision), the volume comparisons
shown in Figure 8 provide a clear basis for phases 8, 9, 10 and 11 development
directional trip distribution to the existing street system. However, this distribution is
substantially different from the trip distribution that was presented in the year 2000 TIS.
The reasons for this difference are:
Y There has been substantial commercial development along 19"' Avenue north of
Oak and in the northeast corner of Oak and 19th in the past 4 years. Since
1260 South 32nd Street West R P.O. Box 80785 Billings, Montana 59108-0785
Harvest Creek TIS Upd��%R'69MJ6) 655-4550 Fax(406) 655-4991 Email marvin@enginc.com
approximately 60% of the residential trip generation is for shopping and the
commercial areas are in close proximity, there has been a major shift in
distribution from south to north.
➢ Durston Road has almost reached its practical capacity. Thus the Oak Street
access now provides an advantage in overall travel time.
Such a shift in traffic distribution was not entirely unexpected. On page 15 of the 2000
TIS, it was stated that "Existing plus site development traffic volume projections do not
necessarily represent a condition that will ever occur, since these developments would
need to be completed within a very limited time ftame. Because of other development
proposals, developments under construction, and general growth in the Bozeman area,
existing traffic volumes will not remain stagnant...traffic projections... are only intended
to illustrate impacts that could be attributed to the subject site development using existing
conditions as a basis. " Thus, year 2004 traffic counts clearly illustrate the conditions
alluded to in the above noted statement. This would also hold true for projections within
this update, since traffic distribution percentages are based on existing street conditions
and not assumed conditions at a time when the development is completed.
Trip Generation
The number of trips associated with phases 8 through 11 must be tied to the number of
trips that were projected for the entire development. The Harvest Creek Subdivision,
which had proposed 541 dwelling units (DU), was projected to have 4955 average
weekday trips (AWT) and 489 net trips during the peak PM hour. Even though final
platting of the subdivision resulted in a total of 530 DU, the original trip generation rates
would apply in proportion to the remaining lots in phases 8 through 11. Thus, the
average trip rates would be: 9.16 AWT trips per DU and 0.90 net trips per DU in the peak
PM hour. Phase 8, 9, 10 and 11 will have 39, 54, 38 and 43 lots or DUs each,
respectively, for a total number of 174 DUs. Trip generation estimates for phases 8
through 11 would then be:
AWT = 1594
Peak PM Hour = 157 (101 enter and 56 exit)
Trip Distribution
Trip distribution estimates were revised based on the traffic demand shifts previously
discussed. Figure 2 illustrates percentage trip distribution based on directional demand,
travel time calculations, and traffic capacity conditions that currently exist. A full 75% of
all Phase 8, 9, 10 and 11 trips will enter and leave the development by way of Oak Street.
Only 15% of all trips would utilize Durston, west of 19t" Avenue, to access N. 19"'
Avenue, while only 7% would use Durston east of 19t" Avenue.
Traffic Assignment & AWT Impacts
Figure 3 present assignment of site traffic to the street system. Site AWT volumes are
shown with corresponding percentages of existing ADT. It can be seen that only Oak
Street, west of N. 19"' Avenue, would have site traffic amounting to more than 10% of
Harvest Creek TIS Update page 2
existing ADT. Since it is not possible to calculate ADT with any greater accuracy than
10% +/-, site traffic projections, which add less than 10% to current ADT estimates, are
not usually evaluated for potential traffic impacts. In this case, all area streets other than
Oak Street would have ADT impacts of 2% or less. However, because the City of
Bozeman has required that impacts on Durston Road be evaluated prior to the continued
development of the Harvest Creek Subdivision, capacity analyses were conducted for
said intersection under existing (2004) conditions and with site-generated traffic
included. Capacity impacts were also evaluated at the intersection of Oak Street and N.
19"' Avenue. Figure 3 illustrates the peak PM hour site traffic turning movement
assignments for both intersections.
Capacity Impacts
In order to determine capacity impacts at the intersections of Oak Street and Durston
Road with 19t" Avenue, it was necessary to calculate existing capacities based on existing
traffic, intersection lane configurations, and existing signal phasing.
The Oak Street intersection has 2 thru-lanes and separate left-turn lanes on the
northbound and southbound approaches and single thru-lanes with separate left-turn lanes
on the east and west approaches. The Oak Street signal currently operates with the
following four phases: 1. SB lead with protected left-turn, 2. NB and SB thru movements
with permissive left-turns. 3. Split phase WB movements, and 4. Split phase EB
movements. The SigCinema program was used to determine the existing capacity based
upon the current geometry and phasing (see attached capacity calculations). It was
determined that the intersection currently operates at a level of service (LOS) "C", but the
WB left and NB thru movements both operate at LOS "D". Observations indicate that it
may actually operate at a lesser LOS due to the actual phasing and timing plan being
used. The capacity calculations indicate a maximum northbound queue of 12 vehicles,
while observations indicate queues in excess of 30 vehicles.
Capacity calculations completed for existing plus site traffic volumes (attached) indicated
that the eastbound left-turn movement would degrade in terms of LOS from "C" to "D".
Since the existing intersection currently has several movements operating below an
acceptable LOS "C", additional capacity analysis was completed based on improved
signal phasing (attached). It was determined that all intersection movements would
operate at LOS "C" or better and overall delay would be reduced by more than 10
seconds per vehicle if split phasing for east/west movements were combined to operate
concurrently during a single phase and if northbound and southbound left-turn
movements were given a-protected phase. The addition of site traffic to this phasing
scheme would provide results very similar to those of the previous analysis. As such, site
traffic at this intersection would not have any measurable impact.
The Durston Road intersection also has 2 thru-lanes and separate left-turn lanes on the
northbound and southbound approaches and single thru-lanes with separate left-turn lanes
on the eats and west approaches. The Durston Road signal currently operates with the
following four phases: 1. NB and SB protected left-turns. 2. NB and SB thru
Harvest Creek TIS Update page 3
movements with permissive left-turns. 3. EB and WB protected left-turns. 4. EB and
WB thru movements with permissive left-turns. It was determined that the signal
currently operates at a level of service (LOS) "C", with all individual movements
operating at or above an acceptable LOS "C".
The addition of site-generated traffic was found to have no measurable effect on the
operational efficiency of the Durston Road intersection. All movements would have
essentially the same LOS, intersection delay and We ratios as exist under current
conditions.
Conclusions
Development of Harvest Creek Subdivision Phases 8, 9, 10 and 11 would generate less
than 1500 trips on the average weekday and less than 160 during the peak PM hour. Due
to existing capacity constraints and delay on Durston Road, and the fact that commercial
development north along N. 19th Avenue has substantially shifted distribution demand,
the majority of newly generated trips would be served by Oak Street. Analysis of the
Oak Street — N. 19th Avenue intersection indicates that the added traffic from Phases 8
through 11 would not be sufficient to create impacts to the overall operations of that
intersection. Existing capacity deficiencies at the Oak — 19th intersection are mainly due
to inefficient signal phasing and timing. Currently, MDT is planning a project to provide
traffic signal coordination using radio interconnect control on the I9th Avenue corridor.
However, we were informed that there are no specific plans to modify signal phasing at
the Oak and 19th intersection. Thus, the signal phasing changes described above would
need to be completed to ensure that all movements operate at a LOS "C" or better.
Signal modifications would require replacing two existing signal indications with two
new P/P arrow indications and possibly rewiring two signal poles.
No measurable effect on operations at the intersection of Durston Road with N. 19"'
Avenue could be detected through capacity analysis. The Durston Road intersection
currently operates at an acceptable LOS "C". The addition of site-generated traffic will
not change that fact, and because the intersection with N. 19th Avenue is the major
determinant of LOS along the entire Durston Road corridor, it is concluded that that
Phases 8, 9, 10 and 11 of the Harvest Creek Development will not have a significant
impact on the Durston Road corridor. At some point in the near future, when Durston
Road is improved and delay is reduced, some increase in development traffic on Durston
may result. However, Oak Street would likely still accommodate the majority of trips to
and from the development.
Respectfully Submitted,
Robert R. Marvin, P.E., P.T.O.E.
Harvest Creek TIS Update page 4
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HCM Analysis Summary 9
EXISTING CONDITIONS DURSTON/19TH AVENUE Area Type: Non CBD
R MARVIN 03/12/2004 Analysis Duration: 15 mins.
PEAK PM HOUR Case: dURSTON& 19TH E
Lanes Geometry:Movements Serviced by Lane and Lane Widths (feet)
ApDroach Outbound Lane 1 Lane 2 Lane 3 Lane 4 Lane 5 Lane 6
EB 2 1 L 12.0 TR 12.0
WB 2 1 L 12.0 TR 12.0
NB 1 3 2 L 12.0 T 12.0 TR 12.0
SB 3 2 L 12.0 T 12.0 TR 12.0
East West North South
Data L T R L T R L T R L T R
Movement Volume v h 234 221 80 108 254 126 139 802 59 130 720 229
PHF 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
%Heavy Vehicles 1 1 1 I 1 1 1 2 1 1 2 1
Lane Groups L TR L TR L TR L TR
Arrival Type 3 3 3 3 3 3 3 1 3
RTOR Vol v h 20 30 25 100
Peds/Hour 0 0 0 0
%Grade 0 0 0 0
Buses/Hour 0 0 0 0
Parkers/Hour(LeftJRight) --- -- _- ___ ___ W -_ ___
Signal Settings: etimed Optimization Analysis Cycle Length: 70.0 Sec Lost Time Per Cycle:16.0 Sec
Phase: 1 2 3 4 5 6 7 8 Ped Only
EB L LTP
WB L LTP
NB L LTP
SB L LTP
Green 5.8 21.6 5.0 21.7 0
Yellowl All Red 4.0 0.0 2.3 1.7 4.0 1 0.01 2.3 1 1.7
Capacity Analysis Results Approach:
Lane Cap v/s g/C Lane v/c Delay Delay
1- -
EB 1-per 191 0.189 0.365 25.3 C
Los
* L ro 147 0.082 0.082 L 0.728 27.3 C
TR 561 0.163 0.308 TR 0.528 23.5 C
WB L er 249 0.000 0.365 24.1 C
L ro 147 0.064 0.082 L 0.288 14.0 B
* TR 555 0.204 0.308 TR 0.663 27.2 C
NB L er 107 0.061 0.367 28.4 C
L ro 128 0.072 0.071 L 0.621 26.3 C
TR 1089 0.250 0.310 TR 0.808 28.7 C
SB L er 107F0.2959
0.367 29.4 C
* L ro 1280.071 L 0.583 24.5 C
* TR 10710.310 TR 0.835 30.2 C
Intersection:Delay=27,5 sec/veh Int. LOS=C Xc=0.80 * Critical Lane Group �i:(v/s)Crit= 0.62
SIG/Cinema v3.03 Page 1
NETSIM Summary Results
EXISTING CONDITIONS DURSTON/19TH AVENUE '
R MARVIN 03/12/2004
PEAK PM HOUR Case: dURSTON& 19TH E
low
Queues Spillback in
Per Lane Average Worst Lane
Lane Avg/Max Speed (% of Peak 720
App Group (veh) (mph) Period) 229 1130
EB L 4/ 6 6.0 0.0
TR 4/ 6 15.8 0.0
z-126
—254
All 12.1 0.0 �-108
W13 L 1 / 3 8.3 0.0 -- - -----------
TR 6 / 7 12.3 0.0 —z•
234 il ! �
221
All 11.9 0.0 80
NB L 3 / 4 5.0 0.0
TR 6/ 8 12.0 0.0 t
1391 59
802
All 11.2 0.0
SB L 4/ 6 3.9 0.0 1 2 3 4
TR 1 7/ 9 11.6 0.0
6 4 0 22 2 2 5 4 0 21 2 2
All 10.0 0.0
Intersect. 11.0
SIG/Cinema v3.03 Page 2
H CNJ Analysis Summary
EXISTING PLUS 8 to 1 1 DURSTON/19TH AVENUE Area Type: Non CBD
R MARVIN 03/12/2004 Analysis Duration: 15 mins.
PEAK PM HOUR Case: DURSTON& 19TH PLUS 8-9
Lanes Geometry:Movements Serviced by Lane and Lane Widths (feet)
Approach Outbound Lane 1 Lane 2 Lane 3 Lane 4 Lane 5 Lane 6
EB 2 1 L 12.0 TR 12.0
WB 2 1 L 12.0 TR 12.0
NB 3 2 L 12.0 T 12.0 TR 12.0
SB 3 2 L 12.0 T 1 12.0 TR 12.0
East West North South
Data L T R L T R L T R L T R
Movement Volume v h 234 227 88 108 259 126 144 815 59 130 727 229
PHF 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
%Heavy Vehicles 1 1 1 1 1 1 1 2 1 1 2 1
Lane Grouts L TR L TR L TR L TR
Arrival Type 3 3 3 1 3 3 3 3 3
RTOR Vol v h 20 30 25 100
Peds/Hour 0 0 0 0
%Grade 0 0 0 0
Buses/Hour 0 0 0 0
Parkers/Hour(LeRlRight) --
_.Si nal Settings:Pretimed Optimization Analysis Cycle Length: 80.0 Sec Lost Time Per Cycle:16.0 Sec
Phase: 1 2 3 4 5 6 7 8 Ped Only
EB L LTP
WB L LTP
NB L LTP
SB L LTP
Green 6.6 25.3 1 5.5 26.6 1 0
Yellowl All Red 4.01 0.01 2.3 1 1.71 4.01 0.01 2.3 1 1.7
Ca a ity Analysis Results Approach:
Lane Cap v/s g/C Lane v/c Delay Delay
1' -LSJS_
EB L er 189 0.190 0.366 27.7 C
* L ro 148 0.083 0.083 L 0.730 29.5 C
TR 574 0.171 0.316 TR 0.542 26.2 C
WB L er 240 0.000 0.366 26.2 C
L ro 148 0.064 0.083 L 0.294 15.8 B
TR 571 0.207 0.316 TR 0.655 29.4 C
NB L er 94 0.122 0.383 29.3 C
L ro 122 0.068 0.068 L 0.704 33.6 C
TR 1171 0.254 0.333 TR 0.763 28.6 C
SB L er 94 0.061 0.383 29.4 C
x L ro 122 0.068 0.068 L 0.634 29.2 C
TR 1152 0.260 0.333 TR 0.782 29.4 C
Intersection:Delay=28.6sec/veh Int.LOS=C Xc-0.77 * Critical Lane Group :Z(v/s)Crit= 0.62
SIG/Cinema v3.03 Page 1
NETSIM Summary Results
EXISTING PLUS 8 to 1 1 DURSTON/I9TH AVENUE
R MARVIN 03/12/2004
PEAK PM HOUR Case: DURSTON & 19TH PLUS 8-9
Queues Spillback in
Per Lane Average Worst Lane
Lane Avg/Max Speed (% of Peak 727 r
App Group (veh) (mph) Period) 2291130
4 n
EB L 6 / 8 4.0 0.0
TR 4 / 7 15.3 0.0
L 126
—259
All 10.0 0.0 �-10808
WB L 2/ 3 7.6 0.0 t ..............
r—
TR 6 / 8 12.3 0.0
234 h � �► — --
227
All 11.8 0.0 88
NB L 3 / 5 4.1 0.0
TR 7/ 9 11.9 0.0 1
144 159
815
All 10.6 0.0
SB L 4/ 7 3.7 0.0 1 2 3 4
TR 7/ 10 11.4 0.0 "' :. a .•,
7 4 0 25 2 2 5 4 0 27 I 2 2
All 9.8 0.0
Intersect. 10.4
SIG/Cinema v3.03 Page 2
HCM Analysis Summary
2004 TRAFFIC OAK ST/N 19TH AVE Area Type: Non CBD
R MARVIN 02/1 1/2004 Analysis Duration: 15 mins.
PEAK PM Case: OAK& 19TH E
Lanes Geometry:Movements Serviced by Lane and Lane Widths (feet)
Approach Outbound Lane 1 Lane 2 Lane 3 Lane 4 Lane 5 Lane 6
EB 2 1 L 12.0 TR 12.0
WB 2 1 L 12.0 TR 12.0
NB 3 2 L 12.0 T 12.0 TR 12.0
SB 3 2 L 12.0 T 12.0 TR 12.0
East West North South
Data L T R L T R L T R L T R
Movement Volume v h 130 99 10 343 173 176 12 824 225 155 628 70
PHF 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
%Heavy Vehicles 0 0 0 2 0 2 0 4 2 2 4 0
Lane Groups L TR L TR L TR L TR
Arrival T e 3 3 3 3 3 3 3 3
RTOR Vol v h 0 75 100 20
Peds/Hour 0 0 0 0
%Grade 0 0 0 0
Buses/Hour 0 0 0 0
Parkers/Hour(LeftJRight) I -- I --- I --- --- --- --- I -
Signal Settings:Pretirned Operational Analysis Cycle Length: 72.9 Sec Lost Time Per Cycle:18.9 See
Phase: 1 2 3 4 5 6 7 8 Ped Only
EB LTP
WB LTP
NB LTP
SB LTP LTP
Green 8.9 17.9 5.0 22.1 0
Yellowl All Red 3.3 1.7 3.3 1.7 4.0 1 0.0 3.3 1.7
Capacity Analysis Results Approach..
Lane Cap v/s g/C Lane v/c Delay Delay
EB
* L 221 0.076 0.122 L 0.620 34.3 C 32.6 C
TR 229 0.061 0.122 TR 0.502 30.6 C
WB
L 435 0.204 0.246 L 0.830 38.0 D 33.4 C
TR 437 0.162 0.246 TR 0.659 27.7 C
\B
L 199 0.020 0.304 L 0.065 18.7 B 45.8 D
* TR 1033 0.294 0.304 TR 0.967 46.1 D
SB L er 102 0.153 0.372 19.8 B
* L ro 121 0.068 0.069 L 0.731 35.0 C
TR 1466 0.208 0.427 TR 0.487 16.3 B
Intersection:Delay= 33.5 sec/veh Int. LOS=C xc 0.87 * Critical Lane Group :E(v/s)Crit= 0.64
SIG/Cinema v3.03 Page 1
I
NETSIM Summary Results
2004 TRAFFIC OAK ST/N 19TH AVE
R MARVIN 02/1 1/2004
PEAK PM Case: OAK & 19TH E
Queues Spillback in !
Per Lane Average Worst Lane
Lane Avg/Max Speed (% of Peak 628 ins
App Group (veh) (mph) Period) 70 1155
EB L 3 / 5 5.5 0.0 4J
TR 2 / 4 12.8 0.0
L 176
r--173
All 9.1 0.0 ;7—343
WB L 6 / 8 6.3 0.0 , .. ��, ,
..
TR 7/ 13 10.5 0.0 1
130 � � iI ? �►
99
All 9.0 0.0 10
NB L 0 / 0 23.5 0.0
TR 9/ 12 9.1 0.0 ',f �22�5
12
824
All 9.1 0.0
SB L 3 / 5 5.8 0.0 1 2 3 4
TR 4/ 6 15.0 0.0
9 3 2 18 3 2 5 4 0 22 I' 3 2
All 13.1 0.0
Intersect. 10.0
SIG/Cinema v3.03 Page 2
HCM Analysis Summary
2004 TRAFFIC Plus Phase 8 to 1 1 OAK ST/N 19TH AVE Area Type: Non CBD
R MARVIN 02/1 1/2004 Analysis Duration: 15 mins.
PEAK PM Case: OAK & 19TH 8TO1 1
Lanes Geometry:Movements Serviced by Lane and Lane Widths (feet)
ApproachlOutbound Lane 1 Lane 2 Lane 3 Lane 4 Lane 5 Lane 6
EB 2 1 L 12.0 TR 12.0
WB 2 1 L 12.0 TR 12.0
NB 3 2 L 12.0 T 12.0 TR. 12.0
SB 3 2 L 12.0 T 12.0 TR 12.0
East West North South
Data L T R L T R L T R L T R
Movement Volume Cy ph) 145 119 17 343 209 176 25 824 225 155 628 96
PHF 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
%Heavy Vehicles 0 0 0 2 0 2 0 4 2 2 4 0
Lane Groups L TR L TR L TR L TR
Arrival TviDe 3 3 3 3 3 3 3 3
RTOR Vol v h 0 75 100 20
Peds/Hour 0 0 0 0
%Grade 0 0 0 0
Buses/Hour 0 0 0 0
Parkers/Hour(LeftIRight) I --- --- I --- --- I ---
Signal Settings:Pretimed Operational Analysis Cycle Length: 72.8 Sec Lost Time Per Cycle:18.9 Sec
Phase: 1 2 3 4 5 6 7 8 Ped Only
EB LTP
WB LTP
NB LTP
SB LTP LTP
Green 1
8.9 17.8 5.0 22.1 0
Yellowl All Red 1 3.3 1.7 3.3 1.7 4.0 1 0.0 3.3 1.7
Capacity Analysis Results A roach:
Lane Cap v/s g/C Lane v/c Delay Delay
Ap
EB
L 221 0.085 0.122 L 0.692 38.2 D 36.4 D_
TR 228 0.077 0.122 TR 0.627 34.4 C
WB
L 433 0.204 0.245 L 0.834 38.5 D 35.1 D
TR 438 0.182 0.245 TR 0.744 31.4 C
NB
L 190 0.042 0.304 L 0.137 19.9 B 45.0 D
* TR 1035 0.294 0.304 TR 0.965 45.7 D
SB L er 103 0.149 0.373 19.6 B
* L ro 122 0.069 0.069 L 0.724 34.3 C
TR 1475 0.215 0.428 TR 0.502 16.4 B
hltersection:Delay= 33.9sec/veh Int.LOS=C Xc=0.88 * Critical Lane Group 5�(v/s)Crit= 0.65
SIG/Cinema v303 Page I
NETSIM Summary Results
2004 TRAFFIC Plus Phase 8 to 1 1 OAK ST/N 19TH AVE
R MARVIN 02/11/2004
PEAK PM Case: OAK & 19TH 8TO1 1
L_
Queues Spillback in
Per Lane Average Worst Lane
Lane Avg/Max Speed (% of Peak 628
App Group (veh) (mph) Period) 96 1155
EB L 4/ 5 5.0 0.0
TR 3 / 4 12.9 0.0
L 176
. 1 —209
All 8.7 0.0 ,--343
WB L 6 / 8 6.8 0.0 I ..... --
TR 8 / 11 9.5 0.0
145 tl t
119
All 8.7 0.0 17 —z
NB L 0 / 1 14.7 0.0
�r
TR 10 / 13 7.5 0.0
t
25 1225
824
All 7.5 0.0
SB L 3 / 4 6.5 0.0 i-- 2 3 4
TR 5 / 7 14.6 0.0
9 3 2 18 3 2 5 4 0 22 3 2
All 13.0 0.0
Intersect. 9.1
SIG/Cinema v3.03 Page 2
HCM Analvsis Summary
2004 TRAFFIC +Phase 8 to 1 1 OAK ST/N 19TH AVE Area Type: Non CBD
R NIARVIN 02/1 1/2004 Analysis Duration: 15 mins.
PEAK PM Case: OAK & 19TH 8to 11 Improve
Lanes Geometry:Movements Serviced by Lane and Lane Widths _(feet)
Approach Outbound Lane 1 Lane 2 Lane 3 Lane 4 Lane 5 Lane 6
EB 2 1 L 12.0 TR 12.0
WB 2 1 L 12.0 TR 12.0
NB 3 2 L 12.0 T 12.0 TR 12.0
SB 3 2 L 12.0 T 12.0 TR 12.0
East West North South
Data L T R L T R L T R L T R
Movement Volume v h 145 119 17 343 209 176 25 824 225 155 628 96
PHF 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95 0.95
%Heavv Vehicles 0 0 0 1 0 1 0 3 1 1 3 0
Lane Groups L TR L TR L TR L TR
Arrival Type 3 3 3 3 3 3 3 3
RTOR Vol v)h 0 75 100 20
Peds/I-four 0 0 0 0
%Grade 0 0 0 0
Buses/Hour 0 1 0 0 0
Parkers/Hour(Left]Right) I --- I --- I --- I --- --- I --- --- I ---
Signal Settings:Pretimed Operational Analysis Cycle Length: 61.9 Sec Lost Time Per Cycle:13.9 Sec
Phase: 1 2 3 4 5 6 7 8 Ped Only
EB LTP
WB LTP
NB L LTP
SB L LTP
Green 22.7 5.0 20.3 0
Yellow All Red 3.3 1.7 4.01 0.0 1 3.3 1 1.7
Capacity Analysis Results Approach:
Lane Cap v/s g/C Lane We Delay Delay
EB
L 328 0.171 0.366 L 0.466 15.4 B 14.5 B
TR 682 0.077 0.366 TR 0.210 13.5 B
WB
* L 459 0.288 0.366 L 0.786 25.6 C 20.7 C
TR 662 0.180 0.366 TR 0.492 15.4 B
NB L er 156 0.000 0.408 29.6 C
L ro 146 0.014 0.081 L 0.086 9.9 A
* TR 1127 0.291 0.328 TR 0.886 30.1 C
SB L er 122 0.064 0.408 21.0 C
* L ro 144 0.081 0.081 L 0.613 21.9 C
TR 1132 0.215 0.328 TR 0.655 20.8 C
Intersection:Delay= 23.3 sec/veh Int.LOS=C XC 0.85 *Ctitical Lane Group :E(v/s)Crit= 0.66
SIG/Cinema v3.03 Page 1
I
NETSIM Summary Results
2004 TRAFFIC +Phase 8 to 1 1 OAK ST/N 19TH AVE
R MARVIN 02/11/2004
PEAK PM Case: OAK & 19TH 8to 1 1 Improve
Queues Spillback in
Per Lane Average Worst Lane i
Lane Avg/Max Speed (% of Peak 628
App Group (veh) (mph) Period) 96 1155
EB L 2/ 4 9.0 0.0
TR 2/ 3 17.0 0.0
L 176
r--209
All 13.3 0.0 .1 1 —343
WB L 51 8 6.6 0.0 ................ _
------
TR 51 8 16.5 0.0
�..
145 -1 � �►
119 —i
All 12.1 0.0 17 —z
NB L 0/ 2 14.2 0.0
TR 7/ 9 11.3 0.0
�22r5
25
824
All 11.3 0.0 v`
SB L 2/ 5 6.3 0.0 1 2 3
TR 4/ 6 13.7 0.0 — --
23 3 2 5 4 0 20 'I 3 2
All 12.3 0.0
Intersect, 11.9
SIG/Cinema v3.03 Page 2
04/19/2004 16:27 4066554991 MARVIN PAGE 01
Marvin & Associates
F" Me
Traffic,Transportation, &Civil rnglneers
To: Robert Murray, P.E. 582-2263
From: Robert R. Marvin
CC: File
Date: April 19, 2004
Re: Harvest Creek TIS Durston Corridor
Bob
Wait Wolfe asked me to Fax this report to you.
04/19/2004 16:27 4066554991 MARVIN PAGE 02
Marvin &,Associa#es
',4ME\— Traffic, Transportation. & Civil Engineers
Walt Wolfe
11258 Cottonwood Road
Bozeman, MT 59718 I April 19, 2004
Re: Harvest Creek Subdivision
Phases 8, 9, 10 & 11 TIS, Update Addenc!urn
i
Dear Walt:
This letter serves as an addendum to the March 15, 2 04 update to the Traffic Impact
Study (TIS) for Harvest Creels West prepared by Malvin & Associates in June 2000.
Information in this letter and attachments is provided �or phases 8, 9, 1.0 and 11 of the
Harvest Creek Subdivision development, with phased 1 thru 7 already having been
completed. From our discussions with City of Bozeman staff, it is our understanding that
the City of Bozeman has requested a complete capacity impact evaluation of the Durston
Road corridor from New Holland Drive to North 19th Avenue in order to determine if the
current level of service (LOS) is at "C" and what capa�ity impacts would be associated
with completion of the Harvest Creek Subdivision. Based on this understanding an
Arterial Street capacity analysis was completed based on the Highway Capacity Manual
(HCM). The following narratives and attachments present the results of our findings.
Current Traffic Volumes
New peak hour turning movement traffic counts were t1ken April 14, 15, and 16, 2004 at
all of the intersections within the study corridor. Figure 1 (attached) presents all of the
turning movement volumes at each intersection between 4:30 and 5:30 p.m. on these
days. The volumes were adjusted to provide balanced how throughout the corridor.
In addition, an electronic traffic counter was placed or Durston between N. 25"' and N.
27`h Streets to record hourly volumes over a 24 hour period. A. summary of the 24 hour
count is attached. It was determined that the peak hour volume is between 3:00 and 4:00
p.m., which has approximately 8.5% of the average daily traffic (ADT). The peak hour
with the greatest directional difference is between 4.00 and 5:00 p.m., which has
approximately 8.4% of the ADT. Upon examining the 15 minute count totals, it was
found that the actual peak hour period was between 4:30 and 5.00 p.m., which has
slightly more than 8.5% of ADT. When comparing the hourly volume variations to other
urban streets it was discovered that the peak hour vol1ume is substantially less than the
10% of ADT found on the typical urban street. A.lio, there is a twelve hour period
between 7:00 a.m. and 7:00 p.m. when 75% of the ADT occurs and the hourly volume
variations during this period are not significant. Overall, traffic demand characteristics
on this corridor do not have high peaking factors.
1260 scum 37.nd sircet West R P,0. Box 80785 i8illing5. Muntana 59108,0785
Harvest Creek TIS Upd�W'W-' ') 655-4550 Fix (406)655-4991 (mail marvin0enginc.com
04/19/2004 16:27 4066554991 MARVIN PAGE 03
Existing Capacity
Capacity calculations using HCS software were completed for each intersection. A
summary of those calculations are attached. It was determined that none of the
intersections or individual movements operate below a LOS "C", except for the
southbound approach to Durston on N. 20t Avenue, which operates at LOS "F". This
situation is the result of a convenience store in the northwest corner of N. 19"' and
Durston. Figure 1 indicates that the right-in/rigbt-out approach to the convenience store
between N. 19tt' and N. 20"'removes approximately 100 vehicles per hour (vph.) from the
eastbound traffic flow on Durston. It also adds approximately 70 vph to the eastbound
flow at N. 20"' Avenue via a southboun,d left-turn. In effect, the convenience store traffic
accounts for over 1 S% of the total traffic on Durston between N. 19"' and N. 20"
Avenues.
In order to determine the existing capacity of the study corridor, two different methods
were used. Synchro 6—Netsijtt is a powerful software programs used to determine
measures of effectiveness for an entire system of intersections. While it is normally used
to evaluate and coordinate signalized intersection systems, it also analyzes tmsignalized
intersections within a signalized grid. The results of the Synchro 6 analysis indicated that
the corridor is currently operating at LOS "B" (results attached). Since our actual
observations of traffic flow did not agree with this assessment, the HCM Arterial module
was used as an alternative evaluation.
The HCM Arterial Capacity method relies on a series of traffic signal calculation inputs.
Since there is only one traffic signal in the corridor, inputs to the program required
additional delay calculations at each unsignalized intersection. The HCM software for
unsignalized intersections calculates delay for left-turn traffic on the thru street, but does
not calculate delay for thru-traffic impeded by left of right taming traffic. Therefore,
separate calculations were required to determine thru-traffic delay at each intersection.
These calculations involve determining the probability of delay based on the number of
turning vehicles, the number of following vehicles, and the control time delay determined
by the HCM calculations. In addition to control delay, deceleration and acceleration
delays were added into each calculation. Summaries of the thru-traffic delays are
attached.
Once thru-traffic delays were calculated at each intersection, the delay 'figures were input
to the HCM Arterial Capacity program (summary attached.). The HCM method resulted
in and overall corridor LOS "C" in both the eastbound and westbound directions. The
calculations were based on criteria for a Class 3 arterial facility, even though Durston
Road would be closer to a Class 4 facility, with lower speeds and numerous accesses. The
average travel speed in the eastbound direction was calculated to be 1.9.6 mph and in the
westbound direction it was 19.2 mp.h.
Harvest Greek T1S Update page 2
04/19/2004 16:27 4066554991 MARVIN PAGE 04
Traf7 tc Assignment& Peak PM Hour Impacts
The March 1.5, 2004 update presented trip distribution and traffic assignment values
which focused on the N. 191h Avenue intersections with Oak and Durston. The
distribution and assignment analysis was subsequently expanded to determine traffic
assignments at each intersection along the study corridor, The attached figure 2
illustrates peak p.m. hour traffic assignment on Durston for the development of Harvest
Creek Subdvvsion Phases 8 thru 11.
Capacity Impacts
Figure 3 (attached) presents the addition of site development traffic assignments to
existing traffic volumes at each intersection along the study corridor. Individual.
intersection capacity calculations were completed and a table comparing existing and
existing plus development traffic was prepared. As can be seen in the attached table, the
additional site traffic would result in no LOS changes at any of the intersections or for
any of the traffic movements_
Having judged the Synchro 6 model results as too optimistic, the HCM Arterial Capacity
(module was once again used to determine the change in capacity of the study corridor.
Again, thru-traffic delays were calculated anal input to the HCM program (attached). It
was determined that the corridor would still operate at an overall LOS of"C". However,
the average travel speed in the eastbound direction would fall from 19.6 mph to 19.5 mph
and speeds in the westbound direction would drop from 19.2 mph to 18.9 mph.
Conclusions
Development of Harvest Creek Subdivision Phases 8, 9, 10 and 11 would generate less
than 1500 trips on the average weekday and less than 160 during the peal.PM hour. Due
to existing capacity constraints and delay on Dwston Road, and the fact that commercial
development north along N. 19th Avenue has substantially shifted distribution demand,
the majority of newly generated trips would be served by Oak Street. Analysis of traffic
impacts on Durston Road between New Holland Avenue and N. 19"' Avenue indicate that
additional traffic attributed to this development would not be sufficient to reduce the
corrid,or's LOS below "C, which is the City of Bozeman's minimum standard. In
addition, it appears that sufficient reserve capacity would remain along the study corridor
to accominodate additional background traffic growth for the next 2 years. It is therefore
concluded that that Phases 8, 9, 10 and 11 of the Harvest Creek Development will not
have a significant impact on the Durston Road corridor.
Respectfully Submitted,
Robert R. Marvin, P.E., P.T.O.E.
Harvest Creek TIS Upd&t9 page 3
04/19/2004 16:27 4066554991 MARVIN PAGE 05
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04/19/2004 16:27 4066554991 MARVIN PAGE 08
Durston -100 ft. West of N. 25th Eastbound
Hour 4/16/2004 0:00 4/1612004 0:00 Avg. %of
Begin THU FRI Weekday Weekday
1 12 12 0,2%
2 15 15 0,3%
3 14 14 0.3%
4 14 14 0.3%
5 58 58 1.0%
6 173 173 3.1%
7 449 449 8.1%
8 404 404 7.3%
9 284 284 6.1%
10 291 291 5.2%
11 355 355 6.4%
12 369 369 6.6%
13 350 350 6.3%
14 383 383 6,9%
15 376 376 6,8%
16 447 447 8.0%a
17 430 430 7.7%
18 333 333 6.0%
19 272 272 4,9%
20 198 198 3.6%
21 135 135 2.4%
22 97 97 1.7%
23 51 61 1.1%
24 39 39 0.7%
Total 1135 4424 6569 100%
9.0%
....... .................... .............. ..
6.00/1 .... ................ -.. _...-- .............. ...
5.0% .......... ............
4.0%
3.0% .......
.......
4h, I
22 23 24
1 2 3 4 5 6 7 8 9 10 11 12 13 1415 16 17 15 19 20 21
04/19/2004 16:27 4066554991 MARVIN PAGE 09
Durston -100 ft. West of N. 25th Westbound
Hour 4/15/2004 0:00 4/16/2004 0:00 Avg. %of
Begin THU FRl Weekday Weekday
1 35 35 0,7%
2 13 13 0.3%
3 12 12 0.2%
4 9 9 0.2%
5 36 36 0.7%
6 68 68 1.4%
7 193 193 $.8%
8 269 269 5,3%
9 222 222 4.4%
10 255 255 5 1%
11 292 292 5,611/0
12 332 332 6,6%
13 206 206 4.1%v
14 383 383 7.6%
15 448 448 8.9%
18 449 449 8.9%
17 461 461 9.2%
1$ 352 352 7,0%
19 285 285 5.7%
20 285 285 5.7%
21 204 204 4 1%
22 116 116 2.3%
2$ 77 77 1.5%
24 32 32 0.6%
Total 1351 3683 5034 100%p
10,0%—
9.0%.............................. ...... .................. . ................. .............. ......_...........
s,o9� ... . ......... ................. ............... ... .........
7.0% .... ................. -............ ... ..... ............. ......
6.0% ...... ............... ... ................. ........
5.0% ...
. ..........
1 2 3 4 9 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2d 21 22 23 24
04/19/2004 16:27 4066554991 MARVIN PAGE 10
Durston -100 ft. West of N. 25th Both Directions
Hour 4115/2004 0:00 4/16/2004 0:00 Avg. %of
Begin THU FRI Weekday Weekday
1 47 47 0.4%
2 28 28 0.3%
3 26 26 0.2%
4 23 23 0.2%
5 94 94 0.9%
6 241 241 2,3%
7 642 642 6.1%
8 673 673 6.4%
9 506 506 4.8%
10 546 546 5.2%
11 647 647 6.1%
12 701 701 6.6%
13 556 556 5.2%
14 766 766 7.2%
1g 824 824 7,8%
16 896 896 8.5%
17 891 891 8.4%
18 685 685 6,5%
19 557 557 5.3%
20 483 483 4.6%
21 339 339 3.2%
22 213 213 2.0%
23 138 138 1,3%
24 71 71 0.7%
Total 2486 8107 10593 100%
Durston Road a N. 25th
Both Directions
B.0°/tl ............................ ....... ...........
(B 7,0% .... ...........
............................... ....... ... . . ......... .......
0 6.0% ..... .........., .......
...... .........
4.0% ............. .........
N
3.0% .......... ......
. . . ........
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 10 17 18 -19 20 21 22 23 24
Hours of the Day
04/19/2004 16:27 4066554991 MARVIN PAGE 11
INDIVIDUAL INTERSECTION CAPACITY IMPACT SUMMARY
EXISTING EXISTING+ Phases$-11
Intersection L.OS V/C Dela sec L,OS VIC Delay(sec)
New Holland $B B 0.01 10.4 B 0.03 12.5
EB Left A 0,00 7.9 A 0,00 8.0
Valley Drive NB B 0.02 10,0 B 0.02 10,1
WB Left A 0.00 7.8 A 0.00 7.8
Springbrook SB B 0.03 13.2 B 0.04 13.3
EB Left A 000 8.0 A 0.00 8,0
Michael Grove NB B 0.09 10.8 B 0,09 10.9
WB Left A 0,09 8,1 A 0,09 8.1
Hunters NB� C 0,25 17.5 C 0.27 18.2
SB C 0.26 20.1 C 0.29 21.7
ES Left A 0.03 8,3 A 0.03 83
WB Left A 0.25 8.1 A 0.06 8.1
Greenway NB B 0.02 11.3 B 0.02 11 A
WB Left A 0.01 8.1 A 0.01 8.2
N 27th 313 C 0.36 22.3 C 0.37 23.2
EB Left A 0.05 8.5 A 0,05 8,6
Western NB B 0,13 13.4 B 0.14 13.7
WB Left A 0.02 8.1 A 0.02 81
N 25th NB C 0.15 19.1 C 0.15 19,7
SB C 0.23 19.4 C 0.24 20.0
EB Left A 0,02 8.3 A 0.02 8.4
WB Left A 0.01 8.1 A 0,01 8.1
2400 Durston NB B 0.02 11.6 B 0.03 11,7
WB Left A 0.01 8.1 A 0.01 8,1
N 23rd NB B 0,03 11.5 B 0.03 11.6
WB Left A 0.01 8.1 A 0.01 8.2
N 22nd NB C 0.06 19.2 C 0.06 19.7
$B C 0.27 23.4 C 0.28 24.4
EB Left A 0,01 8.5 A 0.01 8.1
WB Left A 0,00 8.1 A 0.00 8.5
N 21 st NB B 0.03 13.0 B 0.03 13.1
WB Left A 0.01 8.2 A 0.02 8.3
N 20th NB C 0,21 16.2 C 0.16 18.2
SB E 0,49 38.9 E 0.47 $6.8
EB Left A 0,01 8.5 A 0.01 8.6
WB Left A 0,01 8.2 A 0,01 8,2
N 19th NB C 0,80 28A C 0,77 29.3
SB C 0,87 29.4 C 0.84 29.4
EB C 0,63 25,3 C 0,63 27.7
WB C 0.54 24.1 C 0.54 26.2