Citation

Moreno AT, Garcia A. Accid. Anal. Prev. 2013; 61: 23-32.

Affiliation

Highway Engineering Research Group (HERG), Universitat Politècnica de València Camino de Vera, s/n., 46071 Valencia, Spain. Electronic address: anmoch@cam.upv.es.

Copyright

(Copyright © 2013, Elsevier Publishing)

DOI

10.1016/j.aap.2012.10.013

PMID

23177903

Abstract

Urban road safety management is usually characterized by a lack of quantity and quality of crash data and low budgets. However, fifty four percent of road crashes in Spain take place in urban areas. Moreover, ten percent of urban fatal crashes occur on crosstown roads, which are rural roads that traverse small communities. So, traffic calming measures (TCMs) are often implemented in this part of a rural road that traverses a small community in order to reduce both crash frequency and severity by lowering speeds. The objective of the research was to develop a methodology using continuous speed profile to evaluate safety effectiveness of TCMs on crosstown roads. Given the strong relationship between speed and crash experience, safety performance can be related to speed. Consequently, speed can be used indirectly as a surrogate safety measure. Two indexes were defined as surrogate safety measures based on the continuous speed profile: Ra and Ea. Ra represents absolute accumulated speed variations relative to the average speed, and is inversely related to accumulated speed uniformity; and Ea represents accumulated speed variations above the speed limit, and is directly related to accumulated speeding. Naturalistic data was collected using GPS trackers on twelve scenarios with different TCMs spacing. Then, the indexes were applied to individual observed speed profiles (individual analysis) as well as the operating speed profile (global analysis). The values obtained from individual and global analysis were statistically different. Spacing lower than 110m, which was found optimal on previous research, did not allow drivers to modify their speeds as accumulated speed uniformity was quite similar regardless average operating speed; and, accumulated speeding was also minimized. Consequently, scenarios with implemented TCMs according to technical criteria presented a better design quality. On the other hand, age and gender differences did not seem to affect average speed, nor accumulated speed uniformity or accumulated speeding.

Language: en