Safety Analyst Documents

FHWA Final Report

The FHWA final report presents the objectives and capabilities of the Safety Analyst software in great detail and documents its technical operation. This report was prepared for the Federal Highway Administration (FHWA) to document the development of Safety Analyst.

White Papers

Four separate white papers have been developed to document the benefits and capabilities of the four modules included in the Safety Analyst Analytical Tool. Each white paper provides (1) an overview summary and the expected benefits of the module, (2) detailed capabilities of the module, and (3) a detailed description of the analytical procedures found in the module.

Safety Analyst-Related Case Studies, Evaluations, and Publications

FHWA has developed several case studies related to the implementation of the Highway Safety Manual (HSM). Several of these case studies are directly related and/or refer to Safety Analyst.

An article in the April 2012 edition of ITE Journal titled "How Good Data Lead to Better Safety Decisions" by Jonathan Hughes and Forrest Council, states the following about Safety Analyst:

"ODOT’s collection and use of the enhanced data in SafetyAnalyst has led not only to an improved program for identifying and treating problem sites through the vast array of available analysis options and software capabilities, but also to a number of other benefits. The collection of needed new data has led to improvements in ODOT’s overall data collection processes and better input into its data needs assessment. ODOT is better able to identify data errors, such as site subtypes and specific locations where data are missing or incorrect. Although the primary use is at headquarters, SafetyAnalyst is also providing ODOT districts with the ability to run ad hoc specialized and localized network screenings and site priority lists. For ODOT, the switch to SafetyAnalyst has made it possible to retire legacy analysis tools and antiquated mainframe technology, a long-term goal of the state’s Information Technology Office. The SafetyAnalyst automated evaluation process has led to more efficient and accurate development of crash modification factors for both system-wide and project-level treatments. Finally, SafetyAnalyst has provided critical input and processes to assist ODOT’s efforts in the implementation of the other advanced tools in the HSM." (Pg 16, April 2012 ITE Journal) (Hughes and Council, 2012)

"By better identifying sites with highest ‘excess’ crashes – crash frequencies above the number predicted by the site’s characteristics – ODOT’s use of SafetyAnalyst has led to fewer manual safety studies (i.e., in-field reviews) that district engineers must conduct. Before SafetyAnalyst use, engineers were conducting studies of approximately 600 locations covering 900 miles each year. With SafetyAnalyst use in 2010, the numbers have dropped to 350 locations covering 95 miles. At the same time, the sites ultimately identified are much more hazardous: the goal of an improved identification program. The number of fatalities per identified mile is 67 percent higher than when non-SafetyAnalyst programs were used. Likewise, the number of serious injuries per mile is 151 percent higher and the number of total crashes per mile is 105 percent higher. These higher identification rates indicate much more accurate identification of problem locations." (Pg 17, April 2012 ITE Journal) (Hughes and Council, 2012)

"Ohio’s experience with both the enhanced data and the use of SafetyAnalyst has resulted in not only what it believes to be better safety decisions, but also a number of ‘auxiliary’ nonsafety benefits. Based on current experience, the collection and use of enhanced data can be cost-beneficial and will lead to better safety decisions." (Pg 17, April 2012 ITE Journal) (Hughes and Council, 2012

Safety Performance Functions (SPFs)

This document provides guidance on the development of safety performance functions (SPFs) for use with the Safety Analyst software. SPFs are provided in Safety Analyst and are automatically calibrated using each agency’s data, so it is not necessary for agencies to develop their own SPFs; however, because some agencies may prefer to implement Safety Analyst using SPFs developed with their own agency’s data; this memo provides guidance on the appropriate procedures for SPF development.
These documents provide the tables and graphs of the default SPFs provided in Safety Analyst. If used, these SPFs are automatically calibrated using an agency’s data.
This report documents the development of SPFs for two-lane roads maintained by the Virginia Department of Transportation. This study was undertaken to develop SPFs for use in Virginia in conjunction with Safety Analyst.