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rossing Location: <br />City, State: <br />Reviewer(s): <br />Step I: identify <br />Two-Stae <br />Crossings <br />Step 2: <br />Determine <br />- Critical Headway <br />Step 3 Estimate <br />Probability of a <br />Delayed <br />Crossing <br />Developed by Bolton <br />Uncontrolled Pedestrian Crossing Level of Service <br />Evaluation Worksheet <br />Date: <br />Scenario: <br />Agency: <br />Is there a median available for a two -stage crossing? <br />If yes, does the median refuge meet ADA requirements (4x 4' landing)? <br />If yes, do pedestrians treat this as a two -stage crossing location? <br />Critical headway is the time below which a pedestrian will not attempt to begin cros <br />use judgement to determine whether the available headway is sufficent for a safe crossing. <br />For a single pedestrian: <br />t t <br />Sp <br />crossing 1 <br />tr‘ ts = 7 L = <br />S tc = SI) <br />9 ' , <br />If pedestrian platooning is observed, the spatial distribution of pedestrians should be computed: <br />1. use field observations or estimate platoon size using equation; <br />v evPtc ve—vtc where: N, = total number of pedestrians in crossing platoon <br />crossing 2 <br />O Yes <br />O Yes <br />O yes <br />0 No <br />0 No <br />© No <br />ng the street. Pedestrians <br />N, <br />crossing 1 <br />Vp <br />V Nc v = <br />2. compute,spatiat distribution: <br />- —N INT 15.uvve 1) <br />P We <br />where: t, = critical headway for a single pedestrian (s) <br />L = crosswalk length (ftj <br />Sp = average pedestrian walking speed (ft/s) <br />ts = pedestrian start-up and end clearance time (s) <br />Sp = 3.5 ftjs <br />ts = 3 sec <br />(1.7p v)e(vP—v)tc (ped) <br />vp = pedestrian flow rate (pedis) <br />v = vehicular flow rate across crossing (veh/s) <br />— t, = single pedestrian critical headway (s) <br />.77 <br />crossing 1 <br />=„ <br />3. compute group critical headway: <br />tc,G= tc + 2(Np — <br />crossing 1 <br />t,,G =1 <br />crossing 2 <br />crossing 2 <br />= <br />where: Np = spatial distributions of pedestrians (ped) <br />N, = total number of pedestrians in crossing platoon <br />(ped) <br />\A/c= crosswalk width (ft) <br />8.0 = default clear width used by a single pedestrian <br />to avoid interference with other pedestrians (ft) <br />clear width, if other than 8jf <br />where: t,,3 = group critical headway (s) <br />t, .= single pedestrian critical headway (s) <br />Np =1 <br />crossing 2 Np = spatial distributions of pedestrians (ped) <br />LJ <br />tc,6=1 <br />Probability that a pedestrian will not incur any crossing delay is equal to the likelihood that a pedestrian will <br />encounter a gap greater than or equal to the critical headway immediately upon arrival at the intersection. <br />tc,G <br />N <br />enkFncJ <br />—tc,G1; <br />= 1 — (1 — P)L <br />crossing 1 crossing 2 <br />where: Pb = probability of blocked lane <br />Pd = probability of delayed crossing <br />N = number of through lanes crossed <br />= group critic& headway (s) =t if no platooning <br />v = vehicular flow rate across crossing(vehis) <br />Pb = <br />P <br />d "") <br />HCM Cal <br />eet 1 Page 3 or 5 <br />HCM Evaluation Worksheet <br />