Low Visibility
Visibility distance is reduced by fog and heavy precipitation, as well as wind-blown snow, dust and smoke. Low visibility conditions cause increased speed variance, which increases crash risk. Each year, over 38,700 vehicle crashes occur in fog. Over 600 people are killed and more than 16,300 people are injured in these crashes annually.
National Highway Visibility Web Site - Sponsored by the FHWA Highway Community Exchange (HCX) program, this web site provides a forum for discussions on the topic of weather conditions that affect visibility, especially fog.
Best Practices
- Alabama DOT Low Visibility Warning System (PDF, 97KB)
- California DOT Motorist Warning System (PDF, 110KB)
- Idaho DOT Motorist Warning System (PDF, 134KB)
- New Jersey Turnpike Authority Speed Management (PDF, 202KB)
- South Carolina DOT Low Visibility Warning System (PDF, 99KB)
- Tennessee Low Visibility Warning System (PDF, 401KB)
- Utah DOT Fog Dispersal Operations (PDF, 113KB)
- Utah DOT Low Visibility Warning System (PDF, 97KB)
- Washington State DOT Speed Management (PDF, 161KB)
Publications
To view publications related to low visibility, please select one of the following key words.
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