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Publication Number:      Date:  March/April 2002
Issue No: Vol. 65 No. 2
Date: March/April 2002


National Review of The Highway Safety Improvement Program

The Process of Identifying
High Accident Locations &
Developing Improvements

1. Identify High Accident Locations
A computerized database of information about acidents that occurred on Delaware's roads provides details on accident sites, timing, severity and potential causes. Planners work to identify thirty priority locations annually for detailed study. These can range from a signle intersection to a long section of roadway. The locations change every year for a variety of reasons, such as changes in travel patterns, or due to past improvements. Locations that are currently under study or construction by the Department of Transportation, or that have been studied in the previous 3 years, are not considered as potential candidate sites.
Typical accident report summary, showing accident type, conditions and number of incidents
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2. Identify Accident Patterns
Accident diagrams are created to identify accident patterns. For example, if an intersection has many accidents involving vehicles making left turns, this may indicate sight distance problems or the need for a left-turn signal. Other patterns related to time of day, lighting and weather may provide clues to potential causes and solutions.
Drawing of engineer taking notes and a drawing of an intersection in the background
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3. Conduct Field Studies
Field studies at each of the 30 locations help identify conditions that may be interfering with traffic and pedestrian safety. Engineers look at obstacles, pavement conditions, visibility and lighting conditions, driver speeds, signal timing, available sight distance, road profile (curves, dips, etc.), and bicycle/pedestrian fatalities. As importantly, they also watch driver behavior.
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4. Develop Potential Solutions
Improvements to address accident patterns are identified for each site. These may be as simple as adding a sign or changing pavement markings, or as complex as widening the roadway. Projects are prioritized based on benefit-to-cost ratios; that is, the amount of safety benefit gained compared to the cost of the improvement.
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Drawing of people meeting and reviewing plans
5. Highway Safety Improvement Program Committee Reviews
Improvements are presented to the Highway Safety Improvement Program (HSIP) committee, which is made up of representative from Department of Transportation Planning, Traffic, Roadway Design and External Affairs, as well as regional planning organizations, the Federal Highway Administration and county representatives. At this point, the committee decides whether or not to proceed with the improvements, or whether more detailed studies are required.
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6.Develop Improvement Alternatives
For locations that require more detailed studies, traffic counts, sign and lighting inventories and signal studies may be conducted. Solutions are then developed to address the safety or traffic operational problems the studies identified.
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Drawing of a car driving over a traffic counter
7. Public Involvement
Improvement projects that are of interest to residents or business owners are presented to the public to obtain comments and input regarding improvement alternatives. Several meetings may be held to ensure the public that their concerns and comments have been satisfactorily addressed.

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