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  Capacity Analysis of Pedestrian and Bicycle Facilities:
Recommended Procedures for the "Pedestrians" Chapter of the Highway Capacity Manual


In the United States, the Highway Capacity Manual (HCM), published by the Transportation Research Board (TRB), a unit of the National Research Council, provides guidance for the analysis of transportation facilities. Chapter 13 of the 1994 (update to the 1985) HCM discusses the operational and planning analysis of pedestrian facilities. The HCM pedestrian chapter begins by positing some relationships between pedestrian speed, flow, and density. It continues with analysis procedures for walkways, street corners, and crosswalks. Although offering the traffic engineer the means to analyze the most common pedestrian facilities, some of the procedures rely on incomplete and outdated information. This is unfortunate, because many intersections and walkways in downtown areas, near college campuses, by transit stops, etc., have moderate to heavy pedestrian flows, thus warranting accurate procedures (Figure 1).

The need for new procedures stems from reasons besides outdated methods, however. The heightened importance of "livability" in American communities presents the traffic engineer with the challenge to fully incorporate pedestrians in transportation analysis. The "Pedestrian Preamble" that opens the Florida Walkable Communities Guide provides a unique perspective of the role of the pedestrian in the transportation system: "This community, in providing for trip making, grants pedestrians and motorists of all ages and abilities: rights, privileges, safety, mobility, and access.... Intersections should not favor either motorist or pedestrian, but give equal service and support to both...." (Florida DOT, 1995; emphasis added).

This report summarizes the pedestrian characteristics-related recommendations from the companion volume, Literature Review for Chapter 13, Pedestrians, of the Highway Capacity Manual (Rouphail et al., 1998). It also includes a comprehensive set of recommended service measures of effectiveness, as well as methods for computing selected service measures. Finally, this report provides a summary of recommendations, including a listing of the affected subsections in Chapter 13 of the HCM. This summary is provided at the end of this chapter for ease of reference, and also at the conclusion of the report in section 5.

1.1 A Note on Liability
FIGURE 1
A wide variety of transportation facilities must
effectively serve a wide variety of users

The current HCM provides curves for speeds greater than the maximum freeway speed limits at the time of publishing (TRB, 1994). Consistent with the HCM's demonstrated intent of reflecting actual conditions rather than legal thresholds, the recommendations contained in both this Recommended Procedures for Chapter 13, "Pedestrians." and in the companion Literature Synthesis for Chapter 13, "Pedestrians," (Rouphail et al., 1998) are to help achieve more realistic analytical procedures for the HCM. However, nothing in this Recommended Procedures for Chapter 13, "Pedestrians," or in the companion Literature Synthesis for Chapter 13, "Pedestrians," or in the Highway Capacity Manual, is to be construed as advocating the violation of traffic laws by either pedestrians or drivers. In addition, Recommended Procedures for Chapter 13, "Pedestrians," the companion Literature Synthesis for Chapter 13, "Pedestrians," and the Highway Capacity Manual should not be used as a defense for the violation of traffic laws in any of the States.



1.2 Summary of Recommendations for Design and/or Analysis of Pedestrian Facilities


Recommendation Page(s) Figure Table HCM Ch. 13 Subsections affected HCM variables and adjustments affected
Body ellipse for standing areas 4 2 - introductory narrative only primarily a design recommendation
Body buffer zone for walking 4 - - walkways, street corners, crosswalks walkway LOS E/F threshold changes in Table 13-3
Crosswalk walking speeds 5 - 1 [Ch. 9: Methodology, Input module] new values replace 4.0 ft/s in equation (eq.) 9-8
  - - - Ch. 13: introduction, crosswalks new values replace 4.5 ft/s in eq. 13-14
Grade and stairs walking speeds 7 - - walkway narrative, crosswalks speeds decrease by 0.1 m/s in eq. 13-14 with grades
Crossing speeds for platoons 7 - - N/A -- no change --
Pedestrian start-up time 7 - - N/A -- no change --
Capacity thresholds 8 - - walkways, street corners, crosswalks walkway LOS E/F threshold changes in Table 13-3
Temporal flow variation 8 - - N/A -- no change --
LOS (Level of Service) for walkways 11 5 4 walkways walkway LOS A/B, E/F thresholds change, Table 13-3
LOS for walkways with platoons 12,13 - 6 walkways new table replaces equation 13-3
LOS for transportation terminals 15 - 8 walkways (new measure) new table applies to terminals with platoon flow
LOS for stairs 16 - 9 walkways (new measure) new table applies only to stairs
LOS for crossflows 17 - 10 walkways (new measure) new table serves as secondary check for walkways
LOS for mixed-use paths 21 - 13 walkways (new measure) new table applies only to mixed-use paths
Noncompliance time adjustments 26 - - street corners, crosswalks minor, major red times in equations 13-6, 13-7 change;d
  - - -
-
 effective red time reduced in computing ped delay
LOS for signalized crossingsa 29 - 18 street corners (new measure) new table based on ped delay; space now secondary
Swept-path method for vehicle effects 30 - - crosswalks caution to use only under aggressive driver behavior
LOS for unsignalized crossingsb 32,33 - 20 street corners (new measure) new table based on ped delay
LOS for pedestrian networksc 35,36 - 22 networks (new section) new table shows proposals for analysis of ped networks
Ped delay at signalized crossings 45 - - street corners (new measure) method for computing ped delay
Effective crosswalk time-space 48 - - crosswalks equation 13-13 corrected; calculated TSw will decrease
Crossing time in platoons 49, 60 - - crosswalks new equations replace eq. 13-14 with large platoons
Ped delay at unsignalized crossings 54 - - street corners (new measure) method for computing ped delay
aOffers a comparison with delay-based Level of Service for drivers computed in HCM Chapter 9, "Signalized Intersections"
bOffers a comparison with delay-based Level of Service for drivers computed in HCM Chapter 10, "Unsignalized Intersections"
cOffers a comparison with Level of Service for drivers computed in HCM Chapter 11, "Urban and Suburban Arterials"
dCurrent HCM is ambiguous regarding the definition of minor and major red times (Rmi, Rmj); therefore, the effect of the proposed noncompliance adjustments will depend on the analyst's interpretation of the HCM


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