01475251

Component

https://doi.org/10.3141/2398-02

http://scholar.google.com...+Lan&publication_year=2013

Data from 282 signalized intersections in Charlotte, North Carolina, were used to examine the safety effect of converting the signals to composite LED bulbs. An empirical Bayes before-and-after method was used for the evaluation. Since this was a blanket installation by the city of Charlotte, a comparison group of stop-controlled intersections was used to account for possible trends during the study period. Crash modification factors (CMFs) were estimated for three- and four-leg intersections for eight different crash types including crashes at dawn and dusk and in dark conditions. For three-leg intersections, all CMFs were higher than 1.0; this factor indicates a possible increase in crashes due to the LEDs. However, none of these CMFs were statistically different from 1.0 at the .05 significance level. For four-leg intersections, the CMFs associated with rear-end crashes were lower than 1.0 and statistically significant at the .05 level; this finding indicates a reduction in these crash types following the changeover to the LEDs. There was substantial difference between the sites in terms of the effect of the LEDs. The reasons for these differences are not known at this time. Future research should investigate whether LEDs are more or less beneficial depending on the characteristics of the intersection including type of area, sight distance, traffic volume, and phasing scheme.

01521593

13-1373

English

Bullough, John D

pp 9–18

2013

Transportation Research Record: Journal of the Transportation Research Board

9780309294881

Print

Figures (2) ; References (19) ; Tables (5)

Before and after studies; Crash rates; Highway safety; Light emitting diodes; Signal face; Signalized intersections; Traffic crashes; Traffic signals

Charlotte (North Carolina)

Highways; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure

TRIS, TRB, ATRI

Feb 5 2013 12:21PM

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• Safety Evaluation of Discontinuing Late Nighttime Flash Operations at Signalized Intersections
• Safety of Channelized Right-Turn Lanes for Motor Vehicles and Pedestrians
• Safety Performance Functions Reflecting Categorical Impact of Exposure Variables for Freeways
• Severity Distribution Functions for Freeway Segments
• Spatial Effects on Zone-Level Collision Prediction Models