HomeMy WebLinkAboutSDP201900064 Study Initial Site Plan 2018-12-17HIMPROJECT MANAGEMENT
CIVIL ENGINEERING
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December 17, 2018
Mr. Adam Moore, P.E.
Virginia Department of Transportation
701 VDOT Way
Charlottesville, VA 22911
Regarding: Proffit Road Townhomes
Right and Left -Turn Warrant Analysis
Mr. Moore,
Please find enclosed a warrant analysis for the proposed Proffit Road Townhomes off of Proffit Road between
Pritchett Lane and U.S. 29 Seminole Trail. Forty (40) townhomes are proposed with this development.
The following items are included with this report:
• VDOT Traffic Data
• ITE Trip Generation Summary
• Warrant Analysis Exhibit
• OTISS Trip Generation Reports
Our analysis shows that neither a left turn lane nor a right turn lane/taper is warranted for this project.
If you have any questions you may contact me at jusX@s6imp-engineering.com or by phone at 434-953-6116.
3himr
Engineering, P.C.
The table below summarizes the 2017 VDOT traffic data for the 0.54 mile segment of Proffit Road between Pritchett
Lane and U.S. 29 Seminole Trail, which was used to calculate the peak hour volume (PHV) approaching for the
warrant analysis.
Table 1. VDOT traffic data summary — Proffit Road
AADT
7600
K factor
0.1135
D factor
0.5133
PHV (AADT*K*D)
443
Design Speed (mph)
35
Below is the ITE trip generation summary table that was used in combination with the direction factor of Proffit Road
to determine the PHV right and left turns into the establishment. The OTISS graphs showing the source of this
information are included as Figures 4 and 5.
Table 2. ITE trip generation summary table
AM
PM
Use Description
ITE
Qty
in
out
Total
in
out
Total
Single Family
Detached
210
40
Units
9
26
35
29
16
45
Right Turn
4
15
Left Turn
5
14
The higher number of right and left turns into the site was used in the right and left turn lane warrant analysis, shown
in Figures 1 and 2 below.
2
F-79
IRD
100
0
x
uU
aCA 80
uu
J
C)
S
60
3
F-
C7 40
iz
i
PHV APPROACH TOTAL, VEHICLES PER HOUR
Figure 1. Warrant for right turn treatment (2-lane highway)
The figure above shows that neither a right turn lane nor taper is required for the site. The right turns were taken from
Table 2, and the PHV approach total includes additional traffic that is to be generated by the site.
3
F-58
Warrants for Left Turn Storage Lanes on Two -Lane Highways
Advancing volume and opposing volumes (VPH), speed and percent left turns are used
to determine whether a left turn storage lane is warranted on two-lane highways_
The warrants in table below are taken from the 2011 AASHTO Green Book, Chapter 9,
Section 9.7.3, Page 9-132, Table 9-23. They were derived from Highway Research
Report No. 211, Figures 2 through 19, for required storage length determinations.
WARRANTS FOR LEFT TURN LANES ON TWO-LANE HIGHWAYS
VPH
ADVANCINGVCLUME
OPPOSING
5% 112% 20% 30%
VOLUME
LEFT TURNS LEFT TURNS LEFT RAUS LEFT TURNS
40-MPH DESIGN SPEED'
806
333
240
180
160
906
411)
305
225
200
40D
516
380
275
245
20D
94D
470
350
305
10D
72D
515
390
340
50-MPH DESIGN SPEED'
80D
281)
210
165
135
90D
351)
280
195
170
40D
43D
320
240
210
20D
553
4110
3U0
270
10C
5'F
445
335
205
B0-MPH DESIGN SPEED'
900
23D
170
125
115
806
291)
210
100
14(1
40D
365
270
200
175
20D
451)
330
250
215
100
505
370
275
240
TABLE 3-1
Source: Adapted from 2911 AASHTO
Green Book, Chapter 9, Section 9.7.3,
Page 9-132, Table 9-23
QPF W N9
MOIiJItE 1iPF♦}
---------
— — — —
K Wr(1re
VXMMHI
rlSFT.TJRN
AUWE"
Example:
Two-lane highway with 40-MPH
operating speed
Opposing Volume (VPH) - 600
Advancing Volume (VPH) -440
Left -Turn Volume (VPH) - 44 or 10% of
Advancing Volume
With opposing volume (VPH) of -609 and
10% of advancing volume (VPH) making
left toms, and advancing volume (VPH)
of 305 or more will warrant a left -turn
la ne.
USE DESIGN SPEED IF AVAILABLE, when the Average Running Speed on
IF NOT USE LEGAL SPEED LIMIT. an existing facility is available, the
corresponding Design Speed may be
obtained from Appendix A, Section A-1.
Rev_ 7114
Figure 2. Warrant for left turn lane (2-lane highway)
The highest amount of left turns into the site is estimated in the evening, with 14 left turns out of a total 434 vehicles
advancing. The opposing volume at that time is approximately 458 cars. Since these data values did not quite match
up with the data in Figure 2 above, a graph was created using the values in the 5% left turns category to interpolate a
threshold for the opposing volume that would trigger a left turn lane. See Figure 3 below for the interpolation.
11
9
S
1
30
30
30
a� -
CC
45$
CC
NGTurn Lane
0
�
330 410 434 510 15-V 720
Advancing V011-ime (5; Left Turns)
Figure 3. Interpolation of left turn warrant using data from Figure 2
The graph above shows that for 434 VPH advancing, with 5% left turns, the threshold that would trigger a left turn
lane is about 550. Because 458 opposing VPH are expected, a left turn lane is not warranted.
The following two figures display the source of the estimated trips generated by Proffit Road Townhomes.
®an
------- - --------- - -------
BATH SBORCE:
ITE-TGM 10th Edition
SEARCH BY LAND USE CODE:
210
LAND USE CATEGORY:
(200-299) Residenlial
LAND USE:
210 - Single -Family Detached Housing
INDEPENDENT VARBIBLE (N):
Dwelling lJnits
TIME PERIOD:
Weekday, AM Peak Hour of Generator
SETTINGILOCATION:
General HrhaNSuburban
TRIPT M:
Uhicle
ENTER IVVALUETOCALC!.--ETRIPS:
4R cal••-ulale I
Data Plot and Equation
150�
100i X
50: X
X
0'
___d_________50
X Study Site
Figure 4. OTISS trip generator A.M. peak hour
X
X jX X
X
X XX X
XX
XX X
X�X X X
X 11 X XX X X X
X X X X
x X
XX xx XX X X
J X
XX X
X
X
XX
X X XX
X X X
X
X
16V 150 200 250
%= Number of Dwelling Units
Reset Zoom Restore
— ritted Curve --- Average Rate
DATA 511ATISTICS
And use:
X Single -Family Detached ld--g(210)Click for
re detalls
Independent Vanable:
Dwelling Units
Time Period:
�Neekday
Akt Peak Hour of General r
Setting)Lacetian:
General UlbanlSubulban
Tnp TV":
vehicle
Number of Studies:
157
Avg. Num. of Dwelling Units'.
231
Average Rate'.
0.76
Range of Rates.
036-227
Standard Bevlation
0.25
Fluted Curve Equation:
Lr(T)=091 Ln(X)-029
R2
089
Directional Distribution:
26%entering. 74% exiting
Calculated Imp End.:
5
r
Query Filter
DATA SOURCE:
ITE-TGM 101h Edition
SEARCH BY LAND USE CODE:
210 O
LA MD USE CATECART.
(200-299) Residential
LAND USE:
21D - Single -Family Detached Houeng
INDEPENDENT VARIABLE p10:
Dwelling Units
TIME PERIOD:
LVeekcii PM Peak Hgur o1 Generator
lGeneral Ur-03.burban +I
TRIP TYPE:
/ehiele
ENTER IV VALUE TO CALCULATE TRIP S:
40 Calculate
Data Plot and Equation
mil
100
Gil
X = Number of Dwelling units
Reset Zoom Restore
X Study Site Fitted Curve
Figure 5. OTISS trip generator P.M. peak hour
DATA STATISTICS
xXX Land Use:
SinglrFalnlly Detached Housing (210) Click far
ore defaiis
Independent Variable:
U Iling Unlrs
X Time Period:
Weekday
PM Peak Hour of Generator
Setting+Location:
General lJ rM, Gubulban
Trip Type:
u hlcle
Number of Studies:
165
Avg. Num. of Dwelling Units.
217
Average Rate
1 00
Range of Rates.
Di 2.98
Standard Deviation'.
oat
Fitted Curve Equation:
Ln(T) - C 94 Ln(X)+0 34
R�
--- Average Rate 092
Dlmcdonal Disbibu Don',
64% entering. 36% exiting
Calculated Tnp Entls'.
no