Study Details
Study Title: Investigating the Impacts of Crash Prediction Models on Quantifying Safety Effectiveness of Adaptive Signal Control Systems
Authors: Jin et al.
Publication Date: 2021
Abstract: Introduction: Adaptive Signal Control System (ASCS) can improve both operational and safety benefits at
signalized corridors. Methods: This paper develops a series of models accounting for model forms and
possible predictors and implements these models in Empirical Bayes (EB) and Fully Bayesian (FB) frameworks
for ASCS safety evaluation studies. Different models are validated in terms of the ability to reduce
the potential bias and variance of prediction and improve the safety effectiveness estimation accuracy
using real-world crash data from non-ASCS sites. This paper then develops the safety effectiveness of
ASCS at six different corridors with a total of 65 signalized intersections with the same type of ASCS,
in South Carolina. Results: Validation results show that the FB model that accounts for traffic volume,
roadway geometric features, year factor, and spatial effects shows the best performance among all models.
The study findings reveal that ASCS reduces crash frequencies in the total crash, fatal and injury crash,
and angle crash for most of the intersections. The safety effectiveness of ASCS varies with different intersection
features (i.e., AADT at major streets, number of legs at an intersection, the number of through
lanes on major streets, the number of access points on minor streets, and the speed limit at major streets).
Conclusions: ASCS is associated with crash reductions, and its safety effects vary with different intersection
features. Practical Applications: The findings of this research encourage more ASCS deployments and
provide insights into selecting ASCS deployment sites for reducing crashes considering the variation of
the safety effectiveness of ASCS.
Study Citation: Jin, W., M. Chowdhury, S.M. Khan, and P. Gerard. "Investigating the impacts of crash prediction models on quantifying safety effectiveness of Adaptive Signal Control Systems." Journal of Safety Research, Vol. 76, (2021) pp. 301-313.
Study Report: Download the Study Report Document
CMFs Associated With This Study
Category: Intersection traffic control
Countermeasure: Install adaptive traffic signal control
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.678 | 32.2 |  | All | All | Not specified | Not specified |
| 0.837 | 16.3 |  | All | K,A,B,C | Not specified | Not specified |
| 0.833 | 16.7 | | Rear end | All | Not specified | Not specified |
| 0.263 | 73.7 | | All | K,A,B,C | Not specified | Not specified |
| 0.966 | 3.4 | | Rear end | All | Not specified | Not specified |
| 0.08 | 92 | | Angle | All | Not specified | Not specified |
| 0.533 | 46.7 | | All | K,A,B,C | Not specified | Not specified |
| 0.606 | 39.4 | | Rear end | All | Not specified | Not specified |
| 0.954 | 4.6 | | All | All | Not specified | Not specified |
| 1.004 | -0.4 | | Rear end | All | Not specified | Not specified |
| 0.935 | 6.5 | | All | All | Not specified | Not specified |
| 0.732 | 26.8 | | All | K,A,B,C | Not specified | Not specified |
| 1.032 | -3.2 | | Rear end | All | Not specified | Not specified |
| 0.72 | 28 | | Angle | All | Not specified | Not specified |
| 0.682 | 31.8 | | All | K,A,B,C | Not specified | Not specified |
