Citation

Mohammadipour A, Mohammadipour A, Alavi SH. J. Transp. Saf. Secur. 2020; 12(3): 380-399.

Copyright

(Copyright © 2020, Southeastern Transportation Center, and Beijing Jiaotong University, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/19439962.2018.1490366

PMID

unavailable

Abstract

The influence of raised pedestrian crosswalks (RPC) as traffic-calming measures in urban areas is investigated. Speed reduction due to RPCs is statistically modeled based on their geometric characteristics, and considering before- and on-RPC spot speeds. Geometric dimensions of 23 RPCs including street's width and grade, ramp lengths, top flat crown length and heights, together with 4,672 spot speed observations associated with these RPCs were measured in Qazvin, Iran. To properly model the repeated speed observations on each RPC, the mixed-effects approach is used to estimate the parameters of a linear model. Demonstrating the statistically significant dependence of on-RPC speeds (Vc) on the approaching speeds (Vf) and also the geometric characteristics of the RPC, the proposed model predicts any percentile of Vc as a function of the corresponding percentile of Vf, the RPC's algebraic difference in ramps' grades A1 and A2, and the street width. The results of this study help traffic engineers and decision makers implement optimized RPCs in terms of cross-section dimensions and their locations on streets relative to crowded residential area and school zones where speed reduction is needed.

Language: en

Keywords

Raised pedestrian crosswalk; repeated measurement data; SAS; statistical modeling; traffic safety