Urban Street Segments (Pedestrian Mode)

Highway Capacity Manual (HCM) 2010Vol. 3, Chp. 17

Sabrena Jahan Ohi

Outline

• An “X” is used to indicate an association between a data element and methodology

• A “Blank Cell” is not used as input for the corresponding methodology

Data RequiRement

explanatiOn Of sOme teRm Total walkway width• Distance from outside edge of road ( or face of curb) to far edge of the sidewalk• Buffer width is included• Paved shoulder is not included• For varying width along segment use average value

Effective width of fixed object• Along the inside of the sidewalk• Along the outside of the sidewalk

Buffer width• Distance between outside edge of road ( or face of curb) and the near edge of the sidewalk• Not for pedestrian or vehicle use• For vertical objects of 3ft or more high, spacing need to be recorded

Pedestrian delay• Delay to pedestrians who travel through the boundary intersection along the path parallel to segment

centerline• Delay incurred by pedestrians who cross the subject segment at the nearest signal-controlled crossing• Delay incurred when pedestrians wait at an uncontrolled crossing section (if illegal need not to count)

Proportion of On-Street parking occupied• Sum of the curb line length occupied by parked vehicle divided by the link length• If parking is not allowed value is 0.0

Exhibit 17-39

pROblem DefinitiOn

StepS of methodology

Step 1free flow Speed

Average free flow speed (Spf) is the speed that reflect the condition in which there are negligible pedestrian to pedestrian conflicts and negligible adjustments in a pedestrian’s desired walking path to avoid other pedestrians

Spf = 4.4 ft/s if elderly pedestrian proportion is with in 20% Spf = 3.3 ft/s if elderly pedestrian proportion is more than 20% An upgrade of 10% or more reduce speed by 0.3 ft/s

• Spf =Average free flow speed (ft/s)

Spf = 4.4 ft/s

Step 2AverAge pedeStriAn SpAce

• WE= Effective sidewalk width (ft)• WT= Total sidewalk width (ft)• Wbuf= Buffer width between roadway and sidewalk (ft)• WO,i= Adjusted fixed-object effective width on inside of

sidewalk (ft)• WO,o= Adjusted fixed-object effective width on outside of

sidewalk (ft)• Ws,i= Shy distance on inside (curbside) of sidewalk (ft) • Ws,o= Shy distance on outside of sidewalk (ft) • wO,i= Effective width of fixed objects on inside of sidewalk

(ft)• wO,o= Effective width of fixed objects on outside of

sidewalk (ft)• pwindow= Proportion of sidewalk length adjacent to a

window display (decimal)• pbuilding= Proportion of sidewalk length adjacent to a

building face (decimal)• pfence= Proportion of sidewalk length adjacent to a fence

or low wall (decimal)• vp= Pedestrian flow per unit width (p/ft/min)• vped= Pedestrian flow rate in the subject sidewalk

(walking in both direction (p/h)• Sp= Pedestrian walking speed (ft/s)• Spf= Free-flow pedestrian walking speed (ft/s)• Ap= Pedestrian space (ft2/p)

Step 3ped. delAy At interSection• dpp = delay incurred by pedestrian who travelled through the boundary intersection along a path

parallel to segment center line• dpc = delay incurred by pedestrian who cross the segment at the nearest signal controlled crossing• dpw = delay incurred by pedestrians waiting for a gap to cross the segment at an uncontrolled

location

dpp = 40 s/p [From Chapter 18]

dpc = 80 s/p [From Chapter 18]

dpw = 740 s/p [From Chapter 19]

Step 4ped. trAvel Speed

Combination of time to walk the segment and delay at downstream boundary intersection

Travel speed is less than walking speed, Sp > STp,seg

STp,seg ≥ 4.0 ft/s is desirable STp,seg ≤ 2.0 ft/s is undesirable

Where, •STp,seg = Travel speed of through pedestrians for the segment (ft/s)•L = Segment length (ft)•Sp = Pedestrian walking speed (ft/s)•dpp = Pedestrian delay when walking parallel to the segment (s/p)

• STp,seg < 4.0 ft/s, but considered acceptable but a higher value is desirable

(Sp from step 2; dpp from step 3; L is given)

Step 5pedeStrian LOS ScOre fOr interSectiOn

• Ip,int = Pedestrian LOS score for the boundary intersection

Ip,int = 0.0; for signalized boundary intersection with two-way STOP controlled For signalized boundary intersection Ip,int obtained from chapter 18

Ip,int =3.60 [From Chapter 18]

Step 6pedeStrian LOS ScOre fOr Link

Where,•Ip,link= Pedestrian LOS score for link•Fw= Cross section adjustment factor•Fv= Motorized vehicle volume adjustment factor•FS= Motorized vehicle speed adjustment factor•ln(x) = natural log of x•Wv= Effective total width of outside through lane, bicycle lane, and shoulder as a function of traffic volume [Exhibit 17-18]•W1= Effective width of combined bicycle lane and shoulder [Exhibit 17-18] (ft)•ppk= proportion of on-street parking occupied (decimal)•Wbuf= Buffer width between roadway and available sidewalk (=0.0 if sidewalk does not exist (ft)•fb= Buffer area coefficient= 5.37 for any continuous barrier at least 3 ft high that is located between the sidewalk and the outside edge of roadway; otherwise use 1.0•WA= Available sidewalk width = 0.0 if sidewalk does not exist or WT-Wbuf if sidewalk exists (ft)•WaA= Adjusted available sidewalk width = min(WA, 10) (ft)•fsw= Sidewalk width coefficient = 6.0-0.3 WaA

•vm= Midsegment demand flowrate (direction nearest to the subject sidewalk) (veh/h)•Nth= Number of through lanes on the segment in the subject direction of travel (ln)•SR= Motorized vehicle running speed = (3600L)/(5280tR) (mi/h)

Exhibit 17-18

ConditionVariable when

condition is Satisfied

Variable when condition is NOT

Satisfied

ppk= 0.0 W t=Wol+Wbl+Wos* W t=Wol+Wbl

vm>160veh/h or street is divided

Wv=W t Wv=W t(2- 0.005 vm)

ppk < 0.25 or parking is striped

W1=Wbl+WOS* W1= 10

• W t= Total Width of the outside through lane, bicycle lane and paved shoulder (ft)

• Wol= Width of outside through lane (ft)• Wos

*= Adjusted width of paved outside shoulder; if curb is present Wos*=Wos

-1.5 ≥ 0.0; otherwise Wos*=Wos (ft)

• Wos= Width of paved outside shoulder (ft)• Wbl= Width of the bicycle lane = 0.0 if no bicycle lane is provided (ft)

Step 6pedeStrian LOS ScOre fOr Link

Wt= Wol+ Wbl = 12+5 =17 ft• As ppk=0.2 (≠0.0)

Wv= Wt= 17 ft• As vm= 940 veh/h >160 veh/h

WOS * = 9.5 ft

WOS * = WOS-1.5 = 9.5-1.5 = 8.0 ft

• As street cross section is curved W1=Wbl+WOS

* = 5+8 = 13 ft• As ppk=0.2 (<0.25)

WaA= min (WT – Wbuf , 10) = min (10-5, 5) = 5.0 ft

Repetitive vertical objects like trees are considered to be a continuous barrier in buffer if they are al least 3 ft high with average spacing 20 ft or less

Physical barrier and parked cars between moving vehicles and pedestrians increase the separation space and the perception of service quality

For discontinuous sidewalk in the study segment, each segment need to be evaluated individually and then a weighted average would give LOS score or entire segment

Step 7Link LOS

Determined using pedestrian LOS, Ip,link (Step 6) and average pedestrian space, Ap (Step 2) with the help of Table 17-3

Absence of sidewalk results in pedestrians walking in the street and LOS is determined using Table 17-4

From Step 2, Ap = 32.0 ft2/p From Step 6, Ip,link = 2.51 Link LOS = C [From Table 17-3]

Table 17-3

Pedestrian LOS Score

LOS by Average Pedestrian Space (ft2/p)

>60>40-60 >24-40 >15-24

>8.0-15a ≤8.0a

≤2.00 A B C D E F

>2.00-2.75 B B C D E F

>2.75-3.50 C C C D E F

>3.50-4.25 D D D D E F

>4.25-5.00 E E E E E F

>5.00 F F F F E F

a In cross-flow situations, the LOS E/F threshold is 13 ft2/p

Table 17-4

LOS LOS Score

A ≤2.00

B >2.00-2.75

C >2.75-3.50

D >3.50-4.25

E >4.25-5.00

F >5.00

Step 8rOad crOSSing difficuLty factOr

Crossing Optioni. Altered travel path by diverting to the nearest signalized crossingii. Continuation of original travel path with mid segment uncontrolled

crossing during acceptable gap in motorized vehicle Signalized crossing locationi. Signalized intersectionii. Mid segment signalized crosswalk If crossing is somewhat uniform along the segment Dc is assumed

to be one-third of the distance between the nearest signal controlled crossing

If mid segment crossing is illegal ignore dpw and dpx= min (dpd,60) 0.80 ≤ Fcd ≤ 1.20

Where,•Dd= Diversion distance (ft)•Dc= Distance to nearest signal-controlled crossing (ft)•dpd= Pedestrian diversion delay (s/p)•dpc= Pedestrian delay when crossing the segment at the nearest signal-controlled crossing (s/p)•dpx= Crossing delay = min (dpd,dpw,60) (s/p)•dpw= Pedestrian waiting delay (s/p)•Sp= Pedestrian walking speed (ft/s)•Fcd= Roadway crossing difficulty factor•Ip,link= Pedestrian LOS score for link•Ip,int= Pedestrian LOS score for intersection

Step 8Road CRoSSing diffiCulty faCtoR

Step 9ped. loS SCoRe foR Segment

Ip,seg = Fcd (0.318 Ip,link+ 0.220 Ip,int+ 1.606)

where.,• Ip,seg = Pedestrian LOS score for the segment• Fcd = Roadway crossing difficulty factor• Ip,link= Pedestrian LOS score for the link• Ip,int= Pedestrian LOS score for the boundary intersection

Ip,seg = 1.20 (0.318 [2.51]+ 0.220 [3.60]+ 1.606) = 3.83

Step 10Segment loS

Determined using pedestrian LOS Score, Ip,seg (Step 9) and average pedestrian space, Ap (Step 2) with the help of Table 17-3

Absence of sidewalk results in pedestrians walking in the street and LOS is determined using Table 17-4

From Step 2, Ap = 32.0 ft2/p From Step 9, Ip,seg = 3.83 Link LOS = D [From Table 17-3]

Table 17-3

Pedestrian LOS Score

LOS by Average Pedestrian Space (ft2/p)

>60>40-60 >24-40 >15-24

>8.0-15a ≤8.0a

≤2.00 A B C D E F

>2.00-2.75 B B C D E F

>2.75-3.50 C C C D E F

>3.50-4.25 D D D D E F

>4.25-5.00 E E E E E F

>5.00 F F F F E F

a In cross-flow situations, the LOS E/F threshold is 13 ft2/p

Table 17-4

LOS LOS Score

A ≤2.00

B >2.00-2.75

C >2.75-3.50

D >3.50-4.25

E >4.25-5.00

F >5.00