1. White Paper: Enhancing Statistical Methodologies for Highway Safety Research—Impetus from FHWA
The Federal Highway Administration’s ultimate goal for the Development of Crash Modification Factors (DCMF) program is to save lives by identifying new safety strategies that effectively reduce crashes and promoting them for nationwide installation by providing measures of their safety effectiveness.
Statistical methodologies are heavily used for all studies performed under the DCMF, but these methodologies have been borrowed from other fields and, therefore, have limitations in capability and applicability when used for highway safety research. Secondary goal of the DCMF program is to advance highway safety and related research by establishing sound statistical methodologies, specifically for highway transportation, in cooperation with the American Statistical Association and other statistical communities. This white paper identifies and discusses opportunities for advancing methodologies to estimate crash modification factors (CMFs) and safety performance functions (SPFs) and outlines considerations and future steps that should be taken to encourage researchers to explore these techniques in their research to develop CMFs and SPFs.
http://www.amstat.org/misc/2012-statistical-methodologies.pdf
2. Safety Evaluation of Continuous Green T Intersections
The research documented in this report was conducted as part of the Federal Highway Administration’s (FHWA) Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI-PFS). The ELCSI-PFS studies provide a crash modification factor and benefit-cost (B/C) economic analysis for each of the targeted safety strategies identified as priorities by the pooled fund member States.
This study compares the safety performance of the continuous green T (CGT) intersections with conventional signalized T intersections using treatment and comparison sites from Florida and South Carolina. The results show crashes were reduced for expected total, fatal and injury, and target (rear-end, angle, and sideswipe) crashes at the CGT intersection compared with the conventional signalized T intersection. Further, the B/C analysis indicated that the CGT intersection is a cost-effective alternative to the traditional, signalized T intersection. This report is intended for practicing engineers.
http://www.amstat.org/misc/2012-statistical-methodologies.pdf