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Safety effects of speed limit changes: Use of panel models, including speed, use, and design variables. Transportation Research Record No (2005)
| Venue: | Proceedings of Transportation Research Board Annual Meeting, Washington D.C. (January 2005), and forthcoming in Transportation Research Record.Lee, J., and Mannering, F.L |
| Citations: | 7 - 5 self |
BibTeX
@INPROCEEDINGS{Kweon05safetyeffects,
author = {Young-jun Kweon and Kara M. Kockelman},
title = {Safety effects of speed limit changes: Use of panel models, including speed, use, and design variables. Transportation Research Record No},
booktitle = {Proceedings of Transportation Research Board Annual Meeting, Washington D.C. (January 2005), and forthcoming in Transportation Research Record.Lee, J., and Mannering, F.L},
year = {2005},
pages = {148--158}
}
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Abstract
This work estimates the total safety effects of speed limit changes on high-speed roadways using traffic detector data and Highway Safety Information System (HSIS) data from 1993 to 1996. In order to gauge the total effects, this study applies a sequential modeling approach in which average speed and speed variance models are first estimated, based on roadway design, use and speed limit information. Then, crash counts (of varying severity) are estimated, based on the speed estimates, design, and use variables. The four years of data come from 63,937 “homogeneous ” roadway segments along 7 interstates and 143 state highways in Washington State. A random-effects negative binomial model was selected among several alternative panel and non-panel models for count data. Results indicate that the average road segment in the data set can be expected to exhibit lower non-fatal crash rates up to a 55 mph speed limit. By contrast, fatality rates appear unresponsive to speed limit changes. Fatal and non-fatal rates fall for design reasons, including wider shoulders and more gradual curves, which appear to be key design variables. However, fatal and non-fatal rates move differently when traffic levels rise, with non-fatal rates remaining unchanged and fatal rates falling.
Keyphrases
speed limit change design variable transportation research record non-fatal rate panel model safety effect wider shoulder key design variable use variable state highway several alternative panel washington state average road segment highway safety information system homogeneous roadway segment roadway design count data non-fatal crash rate crash count non-panel model sequential modeling approach speed estimate fatal rate high-speed roadway traffic level rise gradual curve mph speed limit fatality rate traffic detector data average speed total effect limit change random-effects negative binomial model design reason total safety effect speed limit information speed variance model
