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Highway Safety Manual

The Highway Safety Manual (HSM) is an analytical tool published by the American Association of State Highway and Transportation Officials (AASHTO) and supported by the Federal Highway Administration (FHWA). The manual uses traffic and crash data to establish quantitative safety practices to ensure the maximum benefit is obtained from safety investments.  

How Does It Work? 

The HSM introduces a mathematical- and science-based, technical approach that takes the guesswork out of safety analysis. The manual provides tools to conduct quantitative safety analyses, allowing for safety to be evaluated alongside other transportation performance measures, such as traffic operations, environmental impacts, and construction costs. The HSM outlines and provides examples of the following applications:  

  • Identifying locations with the most potential for crash frequency or severity reduction 

  • Identifying factors contributing to crashes and associated potential countermeasures to address these issues 

  • Conducting economic appraisals of potential improvements and prioritizing projects 

  • Evaluating the crash reduction benefits of implemented treatments 

  • Estimating potential effects on crash frequency and severity of planning, design, operations, and policy decisions 

The HSM can be used for projects that are focused specifically on responding to safety-related issues.  

What Are The Benefits? 

Using the HSM can reduce crash-related fatalities, injuries and property damage. HSM provides a more effective use of scarce safety resources. HSM can be used to evaluate which programs and project improvements achieve desired results and show how funds can be reallocated toward those improvements that have the greatest safety benefit. 

Innovation in Motion  

This innovation integrates the HSM procedures and practices into project development at PennDOT. Since PennDOT began widely using the HSM in 2016, safety projects have been more efficiently and effectively implemented. By applying these contemporary road safety management methods, PennDOT maximizes the investment of safety improvements. 

More Information

For more information about this innovation, contact the STIC Management Team.