Safety Analysis and Crash Modification Factors of an Adaptive Signal Control Technology along a Corridor

Osorio, Jesus J.; Benekohal, Rahim (Ray) F.

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https://hdl.handle.net/2142/103134 Copy

Description

Title

Safety Analysis and Crash Modification Factors of an Adaptive Signal Control Technology along a Corridor

Author(s)

• Osorio, Jesus J.
• Benekohal, Rahim (Ray) F.

Issue Date

2019-01

Keyword(s)

• Crash Modification Factor
• Safety Performance Functions
• Highway Safety Manual
• Adaptive Signal Control Technology
• SynchroGreen

Abstract

The main objective of this study is to determine the safety effectiveness of the adaptive signal control technology (ASCT) SynchroGreen using an observational before and after study applying the Empirical Bayes (EB) method. Both national (HSM) and state specific (Illinois) safety performance functions (SPF) were selected and calibrated for the local conditions. A total of 14 SPFs from the HSM and 3 additional from Illinois were calibrated and crash modification factors (CMF) were developed. For multiple-vehicle fatal and injury (FI) crashes at all intersections (four-legged and three-legged combined), the CMF was 0.67, which was not statistically significant at 95 percent confidence level (it was significant at 87 percent). For four-legged-only intersections the CMF was 0.67 as well, which was not significant with 95 percent confidence (it was significant at 85 percent). The 87 and 85 percent are not confidence levels used in practice, however they clearly indicate a decreasing trend in FI crashes due to the implementation of ASCT. For PDO and total crashes, all CMF computed were very close to one indicating no crash reduction due to the implementation of ASCT. The CMF for Illinois KAB crashes (fatal, type A injury, and type B injury crashes combined) was found to be 0.68, which was not significant at 95 percent confidence level (it was significant at 71 percent indicating a decreasing trend in these types of crashes). Paired t-test results showed no reduction in sideswipe same direction, turning, and type

Publisher

Illinois Center for Transportation/Illinois Department of Transportation

Series/Report Name or Number

FHWA-ICT-19-001

ISSN

0197-9191

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/103134

Sponsor(s)/Grant Number(s)

IDOT-R27-127

Copyright and License Information

No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

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