| Title | Developing Crash Modification Factors for Variable Speed Limits |
|---|---|
| Record ID | 82015 |
| Personal Name Creator |
Avelar, Raul Eduardo; Park, Eun Sug; Ashraf, Sruthi; Dixon, Karen K.; Li, Minh; Dadashova, Bahar |
| Personal Name Contributor |
Amjadi, Roya |
| Corporate Creator | Texas A&M Transportation Institute |
| Corporate Contributor |
United States. Federal Highway Administration. Office of Safety Research and Development |
| Publisher | United States. Federal Highway Administration. Office of Safety Research and Development |
| Publication Date | 20210500 |
| Language | English |
| Abstract | The objective of this study was to perform rigorous safety effectiveness evaluations of variable speed limit (VSL) implementation on freeway corridors. To accomplish this objective, the research team compiled safety data from Virginia, Wyoming, and Georgia and used an interrupted time series study design (with a comparison group for Georgia). The team analyzed data using logistic and negative binomial generalized estimating equations models. The results from Wyoming and Georgia produced evidence of significant reductions in several types of crashes. The research team found total crash reductions of 34.4 and 29.2 percent associated with VSL installations in Wyoming and Georgia, respectively. The economic evaluation for these two States generally indicated larger benefits than costs. For Georgia, the estimated benefit–cost (B/C) ratio was 40.38. The economic analysis for Wyoming yielded a more modest B/C ratio of 9.05, though still indicating benefits outweighing VSL installation costs. Results from Virginia were inconclusive as the analysis found no statistical evidence of a change in overall safety. The inconclusiveness of these results is possibly due to the sample size of the after period, the small amount of time the system was active, and the manner in which the VSL was used in the corridor for enhancing safety during adverse weather conditions. |
| Rosap ID | dot:57267 |
| Rosap URL | https://rosap.ntl.bts.gov/view/dot/57267 |
| TRT Terms | Crash modification factors; Highway corridors; Variable speed limits; Traffic models; Time series analysis; Benefit cost analysis |
| Geographical Coverage |
United States |
| Contract Number | DTFH6116D00039-0002 |
| Report Number | FHWA-HRT-21-053 |
| Resource type | Tech Report |
| URL | https://ntlrepository.blob.core.windows.net/lib/82000/82000/82015/FHWA-HRT-21-053.pdf |
| Format | |
| Database | NTL Digital Repository |