The National Academies

NCHRP 08-44(02) [Completed]

Transportation Safety Planning: Forecasting the Safety Impacts of Socio-Demographic Changes and Safety Investments

  Project Data
Funds: $400,000
Research Agency: Arizona State University
Principal Investigator: Dr. Simon Washington
Effective Date: 10/27/2006
Completion Date: 3/31/2010


Analytical tools are needed to enable states and transportation authorities to effectively forecast the safety impacts of socio-demographic changes and safety investments in the transportation planning process. The tools will be applied in a multidisciplinary environment that includes stakeholders from state agencies including metropolitan planning organizations (MPOs), departments of transportation (DOTs), Governors' highway safety offices (GHSOs), and departments of public safety (DPS) to name a few key stakeholders.

Currently, state and metropolitan transportation planning processes are hampered by not being able to accurately forecast safety characteristics and their impacts. Projecting current crash frequencies or rates into the future is not acceptable for planning purposes because forecasts need to account for at least two independent and critical concerns: socio-demographic changes and safety countermeasure investments.

Although there is a significant need to predict future safety (i.e., crashes of various types) at the planning level, there is a dearth of tools available for making such predictions, and most currently available tools are appropriate at the corridor and project levels. NCHRP Project 8-44 resulted in a forecasting tool for addressing socio-demographic changes; however, the tool does not cover a sufficient variety of forecasting conditions nor is the tool user-friendly at present. There is a need for methods and techniques for planning-level safety analysis. These methods and techniques need to be appropriate for predicting aggregate-level safety performance at the planning or traffic analysis zone (TAZ) level and higher.

The primary objective of this research is to develop safety forecasting software and accompanying guidance that independently forecasts changes in socio-demographics and safety investments (engineering and behavioral). The following tasks are envisioned: (1) literature search and meta-analysis of current analytical methods, software tools, and fundamental knowledge of safety countermeasure effectiveness, (2) examine planning process to identify when safety forecasting is needed, (3) develop analytical tool functionality requirements, (4)develop software specifications, (5) prepare and submit interim report, (6) develop and integrat analytical models for safety forecasting, (7) conduct iterative beta-testing of software with MPOs and DOTs, (8) fully develop functionality of software, (9) develop software and tool guidance, and (10) prepare final report that documents the entire project.

This project will build upon existing research such as NCHRP Project 8-44, "Guidebook for Integrating Safety Into Transportation Planning and Decision Making" and NCHRP Project 8-36, Task 26 "Surface Transportation Safety and Investment."

Status: The revised final report has been published.

Product Availability: NCHRP CRP-CD-78, "PLANSAFE: Forecasting the Safety Impacts of Socio-Demographic Changes and Safety Countermeasures"

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