Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 88
88
manually adjusted downward and the other parameters were Pedestrian Intersection LOS
adjusted upward until the second model produced LOS F for
at least one of the streets in the data set. The intersection LOS for pedestrians is computed only for
Although none of the video clips actually produced a LOS signalized intersections according to the following equation
A or F rating (on average) from the video lab participants, the developed by Petritsch et al.112
[ ]:
second model was developed to address potential public Ped Int LOS (Signal) = 0.00569(RTOR +PermLefts)
agency acceptance issues that might arise with adopting the + 0.00013(PerpTrafVol*PerpTrafSpeed)
rst LOS model for pedestrians that might not produce LOS + 0.681(LanesCrossed 0.514) + 0.0401ln(PedDelay)
A and LOS F for at least some streets in the jurisdiction. The -RTCI(0.0027PerpTrafVol - 0.1946) + 0.5997 (Eq. 37)
second model produces a full range of LOS A to F results for
Where
a reasonable range of street conditions typical of urban areas
RTOR +PermLefts = Sum of the number of right-
of the United States.
turn-on-red vehicles and the
The output of both of these models is a numerical value,
number of motorists making
which must be translated to a LOS letter grade. Exhibit 94 pro-
a permitted left turn in a
vides the numerical ranges that coincide with each LOS letter
15-minute period
grade. These thresholds are the same as for the other modes.
PerpTrafVol*PerpTrafSpeed = Product of the traf c in the
Pedestrian Segment LOS outside through lane of the
The segment pedestrian LOS is calculated according to the street being crossed and
following widely used equation [111]: the midblock 85th percentile
PLOS = -1.2276 ln (fLV x Wt + 0.5Wl + fp x %OSP + fb x Wb + fsw x Ws) + speed of traf c on the street
0.0091 (V/(4*PHF*L)) + 0.0004 SPD + 6.0468 (Eq.36) being crossed in a 15-minute
Where
Ped
Ped Seg LOS
SegLOS =S = - 1.2276 ln (W + W + f × %OSP
Pedestrian level of service score for a segment
ol l p + f b × period
× Wb
ln = Natural + fsw × Ws) + 0.0091(Vol 15/L)
log LanesCrossed= The number of lanes being
fLV = Low +volume
0.0004factor
SPD2 + (=1.00
6.0468 unless average annual (Eq. 36) daily crossed by the pedestrian
tra c (AADT) is less than or equal to 4,000, in which
Where case fLV =(2 - 0.00025 * AADT) PedDelay = Average number of seconds
Wt = total width of outside lane (and shoulder) pavement the pedestrian is delayed be-
Ped Seg LOSS = Pedestrian level of service score for a segment
Wl = Width of shoulder or bicycle lane, or, if there is fore being able to cross the
lnun-striped
= Naturalparking
log and %OSP=25 then W =10ft to
l intersection
W olaccount
= Width of
for outside
lateral lane
displacement of tra c
fpW= On-street parking e ect coe cient (=0.50) RTCI = Number of right turn chan-
l = Width of shoulder or bicycle lane
%OSP = Percent of segment with on-street parking melization islands on the
fb =fp
Bu = On-street
er area coe parking
cient e ect coef cient= ( 0.20)
%OSP = Percent
= 5.37 of segment with on-street parking crossing.
for any continuous barrier at least 3 feet high
separating
fb = Bu er area walkway
coef fromcient motor
(
= 5.37 vehicle tra spaced
for trees c. A
discontinuous barrier
20 feet on center) (e.g. trees, bollards, etc.) can be Pedestrian Midblock Crossing Factor
considered a continuous barrier if they are at least 3
Wb = Bu
feet higherand
width are (distance
spaced 20 between
feet on centeredge or of pave-
less. The pedestrian Roadway Crossing Dif culty Factor
Wb = Bu ment and
er width sidewalk,
(distance in feet)
between edge of pavement (RCDF) measures the dif culty of crossing the street between
and sidewalk, in feet)
fsw f=sw = Sidewalk presence coef cient=
Sidewalk presence coe cient(fsw=6-0.3Ws if Ws=10,
( 6 - 0.3W s) signalized intersections. The RCDF worsens the pedestrian
Ws = Width of sidewalk
otherwise fsw = 3.00) LOS if the crossing dif culty is worse than the non-crossing
W s=
Vol = Volume
Width
15 of motorized vehicles in the peak
of widewalk LOS for the facility. It improves the pedestrian LOS if the
For15 widths
minute greater than 10 feet, use 10 feet.
period crossing dif culty LOS is better than the non-crossing dif -
V =LDirectional
= Total
volume of motorized vehicles in the
number of directional through lanes
direction closest to the pedestrian (vph) culty LOS. The factor is based on the numerical di erence be-
SPD
PHF = =
Peak Average
hour running
factor speed of motorized vehicle tween the crossing LOS and the non-crossing LOS. The
L = Total number
traf c (mi/h)of through lanes for direction of tra c pedestrian RCDF is limited to a maximum of 1.20 and a min-
closest to pedestrians.
SPD = Average running speed of motorized vehicle tra c imum of 0.80.
(m/h)
RCDF = Max[0.80, Min{[(XLOS#-NXLOS#)/7.5
Exhibit 94. Pedestrian "Other" Model + 1. 00] , 1. 20} ] ( E q. 38)
LOS Categories.
LOS Numerical Score Where
A 2.00
B >2.00 and 2.75
RCDF = Roadway crossing dif culty factor
C >2.75 and 3.50 XLOS# = Roadway crossing dif culty LOS Number
D >3.50 and 4.25 NXLOS# = Non-crossing Pedestrian LOS number
E >4.25 and 5.00
F > 5.00
= (0.318 PSeg + 0.220 PInt + 1.606)
OCR for page 89
89
Pseg = Ped. Segment LOS number (computed per Exhibit 95. Pedestrian Crossing LOS Score.
equation #20)
Minimum of XLOS Score
Pint = Ped. Intersection LOS number (computed Wait or Divert Delay
per equation #21) (Seconds)
10 1
The crossing difficulty LOS number is computed based on 20 2
the minimum of the waiting-for-a-gap LOS number and di- 30 3
40 4
verting-to-a-signal LOS number. 60 5
> 60 6
XLOS = Min [WaitForGap, DivertToSignal] (Eq. 39)
Where Using the numerical cutoffs shown in Exhibit 96 the final
XLOS = Crossing LOS score (based on Exhibit 96) numerical score is then interpolated between the cutoff val-
WaitForGap = Delay waiting for safe gap to cross. ues based on the probability of obtaining an adequate gap
DivertToSignal = Delay diverting to nearest signalized inter- within the allowed time.
section to cross. For this calculation, the increasing LOS numerical score is
assumed to become logarithmic beyond LOS F.
The delay is converted into a LOS numerical score based
on the minimum of the mean delay waiting for a gap or di-
verting to a signal, according to the values given in Exhibit 95. Divert To Signal LOS
The LOS rating for diverting to the nearest traffic signal to
Wait-For-Gap LOS Calculation cross the street is computed as a function of the extra delay in-
volved in walking to and from the mid-block crossing point to
The Wait-For-Gap LOS is computed based on the ex- the nearest signal and the delay waiting to cross at the signal.
pected waiting time required to find an acceptable gap in the The geometric delay associated with a pedestrian deviation
traffic to cross the street. The acceptable gap is computed as is the amount of time it takes the pedestrian to walk to a con-
a function of the number of lanes, their width, and the aver- trolled crossing and back. To calculate this delay, one must
age pedestrian walking speed, with 2 seconds added. first determine the distance to the nearest crossing. For this
Acceptable Gap = (Number of Lanes * 12 feet/lane) / methodology, this was assumed as one third of the block
3.5 feet/second + 2 seconds (Eq. 40) length. This distance is then divided by the pedestrian's walk-
ing speed (assumed to be 3.5 feet/second) to obtain the geo-
The expected waiting time until an acceptable gap becomes metric delay:
available is computed as follows:
Ped Geometric Delay = 2/3 * (Block Length)/
1
MeanWait = [ exp ( t ) - 1] - t Ped Walking Speed (Eq. 42)
(Eq. 41) The control delay at the intersection is calculated as shown
in the HCM [113]:
Where
t = The acceptable gap plus the time it takes for a vehicle Ped Control Delay = (Cycle Length - Green Time)2/
to pass by the pedestrian. (2*Cycle Length) (Eq. 43)
The average pass-by time = Average Vehicle Length/
The total delay is the sum of the two:
Average Speed, converted to seconds.
= The average vehicle flow rate in vehicles per second. Total Ped Deviation Delay = Ped Geometric Delay
Exp = The exponential function + Ped Cycle Delay (Eq. 44)
Exhibit 96. Pedestrian LOS and Delay Thresholds.
Pedestrian LOS Delay Threshold Equivalent LOS Numerical Equivalent LOS Midpoint
Seconds Score Range Score
A 10 1.5 1
B 20 >1.5 and 2.5 2
C 30 > 2.5 and 3.5 3
D 40 > 3.5 and 4.5 4
E 60 > 4.5 and 5.5 5
F > 60 > 5.5 6
For this calculation, the increasing LOS numerical score is assumed to become logarithmic beyond LOS F.
OCR for page 90
90
Exhibit 97. Evaluation of Proposed Pedestrian Model and HCM Against Video Lab Results.
Sidewalk Pedestrian Outside Shoulder On-Street Buffer Dir. Traffic Traffic Video HCM Model Model
Clip Location Width Flow Rate Lane Width Parking Barrier Width Vol. Lanes Speed LOS LOS #1 #2
(ft) (pph) (ft) (ft) (%) (Y/N) (ft) (vph) (lanes) (mph) LOS LOS
215 7th Ave at 15th St, N side 8 60 12 0 50% Yes 7 170 1 25 B E B B
227 Grant Ave at California St, E side 6 200 16 0 0% Yes 4 630 2 30 B B C C
230 3rd St at Mission St, E side 6 220 12 0 0% No 5 220 2 30 B D C D
221 Stockton St at Washington St, E side 4 640 16 0 0% Yes 3 0 1 30 B E B B
224 Grant Ave at Jackson St, E side 4 1320 12 0 100% Yes 2 80 1 30 B E B B
228 Post St at Stockton St, S side 6 180 10 0 40% Yes 1 370 1 30 B D B C
226 Geary Blvd at Divisadero St, S side 9 190 20 0 50% Yes 5 1180 2 40 B D D D
232 Hillsborough, Arm. to Tamp., N side 6 0 16 4 0% No 0 540 1 45 B B D D
229 Post St at Stockton St, S side 6 280 10 0 40% Yes 0 310 1 30 B D B B
205 Alumni Dr at Magnolia Dr, N side 10 0 12 4 0% No 10 200 2 30 C B C C
211 Bearss Ave at North Blvd, N side 4 0 12 0 0% No 5 570 1 45 C A B C
214 Dale Mabry at Tampa Bay, E side 9.5 0 12 5 0% No 35 2030 3 45 C E D E
225 Geary Blvd at Divisadero St, S side 9 280 20 0 50% Yes 5 1050 2 40 C C D D
218 Market St at Kearney St, N side 15 340 12 0 0% No 12 60 1 30 C C B B
222 Stockton St at Broadway St, E side 6 610 16 0 50% Yes 3 220 2 30 C E C C
219 Stockton St at Clay St, E side 7 640 16 0 100% Yes 4 150 1 30 C E B B
220 Stockton St at Clay St, E side 7 820 16 0 100% Yes 4 150 1 30 C D B B
223 Stockton St at Broadway St, E side 6 1600 16 0 50% Yes 3 0 2 30 C D A A
210 Magnolia Dr at Holly Dr, W side 0 0 12 0 0% No 0 160 2 30 C C C C
216 21st St at 7th Ave, W side 6 0 12 0 0% No 0 360 1 30 C A C C
217 21st St at 7th Ave, W side 6 0 12 0 0% No 0 300 1 30 C E B C
203 Collins Blvd at Alumni Dr, E side 10 0 12 4 0% No 15 270 2 30 D D C C
204 Collins Blvd at Alumni Dr, E side 10 0 12 4 0% No 15 160 2 30 D E B C
231 Dale Mabry, State to Carmen, W side 5 0 12 0 0% No 6 570 1 35 D B D D
201 Holly Dr at Magnolia Dr, N side 0 0 10 0 0% No 0 270 2 20 D E D E
209 Fletcher at Bruce B Downs, S side 0 0 12 4 0% No 0 2170 4 45 D A E F
206 Fowler Ave at 56th St, S side 5 0 12 5 0% No 23 1690 4 50 E E D E
208 Fletcher at Bruce B Downs, S side 0 30 12 4 0% No 0 1750 4 45 E C E F
% Exact Match to Video Rating 100% 25% 43% 43%
% Within 1 LOS of Video Rating 100% 43% 86% 79%
Notes:
On-Street Parking = Percent of on-street parking lane occupied by parked vehicles.
Barrier is presence of trees, or other barrier between pedestrian sidewalk and street.
Traffic lanes is number of lanes in direction of travel closest to pedestrian.
Video LOS is the mean of the letter grade LOS ratings reported by subjects in video lab.
Model LOS is the LOS grade predicted by the proposed pedestrian LOS model.
