Speed is especially lethal for vulnerable users like people walking and biking.
High Speeds Dramatically Increase the Severity of Collisions Research consistently shows the destructive potential of vehicles traveling at high speeds. Our Los Angeles data confirm these findings: Unsafe speed contributed to 35 percent of all fatal collisions Citywide.
Speed is especially lethal for vulnerable users like people walking and biking.
The effect of vehicle speed on the likelihood of survival depends on the transportation mode of the other party involved in the collision. For vehicle-to-vehicle collisions, numerous technological advances in vehicle design have improved the likelihood of survival. Unfortunately, people walking or bicycling do not have many of the same protective features, making them more vulnerable when hit by vehicles traveling at speeds greater than 20 miles per hour. A U. S. Department of Transportation review of studies to date found that increasing vehicle speed from 20 miles per hour to 40 miles per hour increases the likelihood of a pedestrian death when hit from 10 percent to 80 percent. 7
This explains why arterial streets, which combine a high number of vulnerable people with cars moving at relatively high speeds, are so deadly and make up a high proportion of the HIN.
IF HIT BY A PERSON DRIVING
20 MPH
CHANCES OF SURVIVAL
80 %
40MPH
10 %
7 W. A. Leaf and D. F. Preusser, Literature Review on Vehicle Travel Speeds and Pedestrian Injuries( Washington, D. C.: U. S. Department of Transportation, National Highway Traffic Safety Administration, October 1999).
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