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FHWA Home / Safety / Local and Rural Road / Training

Improving Safety on Rural Local and Tribal Roads – Site Safety Analysis – User Guide #1

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4.0 Options for Additional Activities

Looking forward from implementing the particular treatment at one site, there are a number of additional actions the agency could take. Staff could:

Regression to the Mean

On an annual basis, the number of crashes at a site will fluctuate up and down. Over time, if nothing changed at the site (e.g., traffic volume, surrounding land use, weather, driver demographics), the frequency of crashes at the site would converge on an average crash frequency. This is called regression to the mean. Regression to the mean is the tendency for a site to experience a period with a comparatively high crash frequency followed by a period with comparatively low crash frequency.

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Page last modified on October 4, 2013.
Safe Roads for a Safer Future - Investment in roadway safety saves lives
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000