Study Details
Study Title: A Study of the Safety Impact of Speed Limit Reduction on Abu Dhabi Freeways
Authors: Abdelany et al.
Publication Date: 2014
Abstract: This study aims at evaluating the safety impact of reducing the speed limit on two major freeways in Abu Dhabi, United Arab Emirates, from 160 km/h o 140 km/h. A third freeway with unchanged speed limit was used as a comparison. Data was made available from the Abu Dhabi Police Head Quarters that includes collision records, frequency, location, an severity, along the three freeways in this study. Five years of collision records have been studied. Four years before the treatment and one year after. Average Annual Daily Traffic, lengths of road segments, number of lanes a each segment, speed treatment, existence of trucks, an construction works along the road are all considered as covariates in the developed collision prediction models. Furthermore, these models were developed for minor, intermediate, serious injury, fatal, and total number of collisions. An Empirical Bayes before and after analysis was conducted in order to investigate the safety impact of the treatment. Using the developed models and the Empirical Bayes, it was found that reducing the speed limit does not improve safety.
Study Citation: Abdelnaby, A., Y. Albadi, K. Ismail, and Y. Hassan. A Study of the Safety Impact of Speed Limit Reduction on Abu Dhabi Freeways. Presented at the 93rd Annual Meeting of the Transportation Research Board, Paper No. 14-5667, Washington, D.C., (2014).
CMFs Associated With This Study
Category: Speed management
Countermeasure: Lower posted speed from 160 km/h to 140 km/h
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.8321 | 16.79 |  | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.5561 | 44.39 | | All | K | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.8172 | 18.28 | | All | A | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.8301 | 16.99 | | All | A,B,C | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.9806 | 1.94 | | All | B | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.8435 | 15.65 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 1.066 | -6.6 | | All | K | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.9655 | 3.45 | | All | A | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.9591 | 4.09 | | All | A,B,C | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.6674 | 33.26 | | All | B | Principal Arterial Other Freeways and Expressways | Not specified |
