01623695

Component

https://doi.org/10.3141/2636-03

The safety effects of multiple treatments have recently emerged as an important issue of validation for the Highway Safety Manual procedures to improve performance of the predictive process. To estimate the combined safety effects of multiple crash modification factors (CMFs) more reliably, several combining approaches have been suggested. However, several critical issues still exist for the combining methods, such as overestimation, region-specific method, and a nonscientific approach. Therefore, this study suggests a novel adjustment method to combine multiple CMFs and to enhance the reliability of combining the safety effects of multiple treatments. Various combinations of CMFs for single and multiple treatments were estimated or obtained from previous studies and used for an exploratory analysis. Moreover, an alternative combining approach with the development of an adjustment function was suggested through comparison with the existing combining methods by using a multicriterion decision-making process. The results show that the proposed alternative combining method provides better estimates than the existing methods and can account for different roadway types and severity levels. Thus, it can be recommended that the safety effects of multiple treatments be estimated with the proposed new combining approach to overcome the overestimation issue and produce results that are more reliable.

01626186

17-00439

English

pp 15–22

2017

Transportation Research Record: Journal of the Transportation Research Board

9780309441773

Digital/other

References (26) ; Tables (7)

Crash modification factors; Crash rates; Crash severity; Highway factors in crashes; Highway safety; Mathematical prediction

Highways; Safety and Human Factors

TRIS, TRB, ATRI

Dec 8 2016 10:04AM

• Application of Highway Safety Manual Method for Ramp Crash Prediction to Loop and Diamond Ramps
• Developing Crash Modification Factors for Horizontal Curves on Rural Two-Lane Undivided Highways Using a Cross-Sectional Study
• Development of Crash Modification Factors for Uncontrolled Pedestrian Crossing Treatments
• Evaluation of Safety Performance Functions Based on Experimental Design Using a Cross-Validation Method
• Exploring the Need for Region-Specific Calibration Factors
• Implementing Highway Safety Manual Life-Cycle Benefit–Cost Analysis of Safety Improvements
• Investigation of Skew Angle and Other Factors Influencing Crash Frequency at High-Speed Rural Intersections
• Safety Effects of Low-Cost Systemic Safety Improvements at Signalized and Stop-Controlled Intersections
• Safety Performance of Flashing Yellow Arrow for Protected–Permissive Left-Turn Signal Control in Central Illinois