Safety Benefits of Median Installations in Utah

• Authored by:  Dr. Grant G. Schultz (PhD)
• Event:  2012 National Conference on Access Management

Brigham Young University

Outline

• Introduction
• Background
• Selection of Analysis Sites
• Analysis Procedure
• Raised Median Results
• Conclusions

Conclusions

• Hierarchical Bayesian Poisson regression is an effective method for evaluating before and after studies of traffic safety projects
• The methods are robust to the use of only small amounts of data
• Any type of crash may be modeled and multiple covariates may be included in extremely flexible ways
• This study provides an analysis of safety at locations where raised medians have been installed
• Results indicate a significant improvement in terms of both crash frequency and frequency of severe crashes along corridors where raised medians were installed
• Results from all sites show frequency of crashes reduced by 39% and frequency of severe crashes reduced by 44% after the installation of raised medians
• Raised medians are one tool to aid in meeting the goal of ZERO Fatalities in the state of Utah