01478084

Component

https://doi.org/10.3141/2386-21

http://scholar.google.com...ouny&publication_year=2013

The objective of this study was to evaluate the safety performance of a sample of intersections that had been improved with the implementation of certain safety countermeasures targeting right-turn collisions in the city of Edmonton, Canada. A full Bayes approach was used to determine the effectiveness of the improvements by employing a before-and-after design with matched (yoked) comparison groups. Three linear intervention models were considered: a multivariate model that modeled treatment effects as a gradual change, a similar model with the addition of a jump treatment effect, and a univariate model that specifically analyzed right-turn collisions. The results indicated that the safety improvement program was effective; up to 40% of right-turn collisions were reduced. Despite the small sample size, these reductions were statistically significant. The results show the usefulness of the full Bayes technique in performing before-and-after evaluations of traffic treatment programs and in eliminating the need for a reference population and also in allowing for additional types of analysis, including multivariate analysis (modeling collisions of different types and severities at the same time), temporal effects (for both treatment and long-term trends), and greater freedom in the selection of error structure.

01514599

13-4869

English

pp 189–194

2013

Transportation Research Record: Journal of the Transportation Research Board

9780309287036

Print

Figures (1) ; References (22) ; Tables (5)

Before and after studies; Countermeasures; Crashes; Multivariate analysis; Right turns; Traffic safety

Safety Performance Functions

Temporal effects

Edmonton (Canada)

Data and Information Technology; Highways; Safety and Human Factors; I80: Accident Studies

TRIS, TRB, ATRI

Feb 5 2013 12:56PM

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