Research Papers (2009 – 2013)

Abstract

Excessive and inappropriate speed is the number one road safety problem in many countries and is considered an aggravating factor in the severity of all crashes. Speeding in residential areas is one aspect of a larger set of problems related to speeding and traffic safety. To address the speeding problem in residential areas, the City of Edmonton initiated a pilot program in 2010 to reduce the posted speed limit from 50 to 40 km/h within six residential communities. The initial results, six months after the implementation of the pilot program, showed significant reduction in the mean speed in the treated communities. The objective of this paper was to conduct a follow-up analysis to examine whether the impact of the posted speed limit reduction was sustained one year after the pilot program was implemented. This objective was accomplished by analyzing the speed and compliance data in a before-after experimental design involving a comparison group. Three types of analysis were conducted that included comparing the results of the short-term (six months after) to the long-term (one year after), comparing the baseline (prior to reducing the speed limit) to the short-term and comparing the long-term to the baseline. Results showed that the treatment was effective in reducing the mean speed both for short-term and long-term, though the effectiveness was reduced over time. The results of the compliance to the posted speed limit analysis showed that the drivers in the treated communities were much less likely to comply with the lower speed limit.

Shewkar E. Ibrahim, Karim El-Basyouny, Tazul Islam