California DOT: "Quantitative Road Safety Analysis in Value Engineering: A Case Study"

"Quantitative Road Safety Analysis in Value Engineering: A Case Study" was presented at a poster session at the 2013 TRB Annual Meeting. Click here to view a PDF version of the poster.

Abstract:

An important aspect of value engineering in road design involves consideration of the value aspects of road safety performance across the full range of design features being considered. In this paper we describe the application of a broad safety analysis toolset that enabled a Value Engineering Team to explicitly and quantitatively assess proposed context sensitive design improvements to the Niles Canyon Road corridor in Alameda County, California. The study was sponsored by the California Department of Transportation, facilitated by Value Management Strategies, Inc., and Delphi-MRC (a member of the MMM Group) conducted the safety analysis.

The main objectives of this study were to: • Assess the safety performance of the corridor • Determine if and where safety improvements should be considered • Examine contributing factors and identify potential countermeasures • Estimate the safety benefit associated with each countermeasure • Recommend a set of countermeasures to consider over the short, medium, and long term and determine the expected safety benefit corridor-wide.

The existing road safety performance of the corridor was assessed based on a “lines of evidence” approach. This methodology examined the safety performance of the study area using a variety of tools and techniques that assessed the corridor first individually, and then collectively. Findings from this process were used to identify priority locations for safety improvements, to identify appropriate countermeasures, and to quantify the expected safety benefits of various improvement scenarios.

Tools and techniques that were applied in the assessment and evaluation process included: a safety-oriented field review; risk-based prioritization based on qualitative ratings of severity and likelihood; collision data analysis and mapping using GIS toolsets; a review of geometric design and traffic operational elements incorporating the Highway Safety Manual (HSM), Interactive Highway Safety and Design Model (IHSDM), and Highway Capacity Manual (HCM); Collision Modification Factors (CMFs) established through research; and the Roadside Safety Analysis Program (RSAP).