Highway Safety Manual Breaks New Ground

The American Association of State Highway and Transportation Officials (AASHTO) and national researchers including Kittelson & Associates, Inc. partnered to develop the first edition Highway Safety Manual (HSM). The HSM provides professionals with tools to evaluate and quantify safety along with other transportation performance measures, such as traffic operations, environmental impacts, mobility measures and construction costs. “Research development and efforts to compile the HSM took a decade and required thousands of volunteer hours through the Transportation Research Board.” said John Zegeer of Kittelson’s Ft. Lauderdale office, who served as Principal Investigator in the production of the First Edition of the HSM.

The HSM can and has been used for a range of projects, including multimodal transportation projects. For example, it provides a method to quantify changes in crash frequency as a function of roadway cross-sectional features such as lane and shoulder width and/or the presence of on-street parking. With this method, professionals can compare the expected change in crash frequency of different design alternatives with the operational benefits or environmental impacts of these same alternatives. HSM users can also compare the costs of, say, constructing a left-turn lane on a two-lane rural road with the estimated safety benefits of reducing a certain number or type of predicted crashes.

Along with traditional applications, the HSM can also be used to conduct quantitative safety analyses on projects that historically have not benefited from this type of evaluation, such as corridor planning studies. It is also being used within capacity enhancement projects as well as intersection studies.

The HSM outlines and provides examples of several applications. This innovative manual helps users:

“¢ Identify sites with the most potential for crash frequency or severity reduction;
“¢ Identify factors contributing to crashes and associated potential countermeasures to address these issues;
“¢ Conduct economic appraisals of potential improvements and prioritize projects;
“¢ Evaluate the crash reduction benefits of potential treatments; and
“¢ Estimate potential effects on crash frequency and severity of planning, design, operations and policy decisions.

The HSM is one of several tools emerging from a burgeoning safety culture. To learn more about the HSM, visit the HSM wesbite. For information about Kittelson’s HSM training workshops in 2011, visit their calendar of events or contact Erin Ferguson by email.