Data Analysis
Overview
The analysis of safety data enables agencies to better understand the nature of the problems and develop appropriate countermeasures to address transportation safety. The results of safety data analyses can be incorporated into a transportation safety plan. Three primary approaches to safety data analysis are presented below: contributing factors analysis, systemic safety analysis, network screening, and site safety analysis/road safety audits. An overview of these data analysis methods is also presented in these guides:
- Tribal Crash Reporting Toolkit – Data Analysis Tool
- Local Road Safety Plans Do-It-Yourself website: Use Safety Data
- Improving Safety on Rural Local and Tribal Roads — Safety Toolkit
NEW!
An updated and expanded version of the Tribal Crash Reporting Toolkit is currently being developed that will include software to conduct safety analysis. This project is a partnership between Trinidad Rancheria, Federal Highway Administration, and the National Highway Traffic Safety Administration. The contractor for this effort is Qk4 and the project web page is https://www.qk4.com/services/native-american-services/tribal-crash-data-reporting-resources/
Contributing Factors Analysis
Examining crash data to identify trends in crash circumstances. This analysis is useful when preparing to write a safety plan.
- Tutorial: How to conduct a contributing factors analysis using pivot tables
- Recorded Web Presentation: Contributing Factors Analysis using pivot tables
- Crash Tree Diagram Tool
Systemic Safety Analysis
Rather than managing risk at certain locations, a systemic approach takes a broader view and evaluates risk across an entire roadway system
- FHWA Systemic Safety Analysis Toolkit
- Example from Confederated Salish and Kootenai Tribe
- Example from Sisseton Wahpeton Oyate Tribe
- Recorded Web Presentation: Systemic Safety Analysis
- Systemic Safety Tools in the Do-It-Yourself Local Road Safety Plans Toolkit
Network Screening
Analyzing crash data along a roadway network to determine areas of high crash frequency.
- Network Safety Analysis – User Guide
- http://safetyanalyst.org/
- Recorded Web Presentation: Network Screening Analysis
Road Safety Audits & Site Safety Analysis
Detailed study of a particular location’s safety concerns by an independent, multi-disciplinary team of safety professionals.
- Road Safety Audits Workshop (4 hour)
- Video: Introduction to Road Safety Audits (4 minutes)
- Video: Road Safety Audits: What they are and how to get started (11 minutes)
- Video: Road Safety Audits: A Breif Overview of the 8-step process (6 minutes)
- Recorded Web Presentation: Site Safety Analysis
- FHWA Office of Safety Road Safety Audit Resources page, http://safety.fhwa.dot.gov/rsa/
- Federal and Tribal Lands Road Safety Audits: Case Studies [ PDF 2.17 MB]
- RSA Toolkit for Federal and Tribal Lands [PDF 1.94 MB]
- The Toolkit serves as a starting point, providing information to FLMAs and Tribes about partnerships needed to build support, available funding sources for the program and improvements, tools to conduct RSAs, and resources to identify safety issues and select countermeasures.