Safe Stopping DistancesBob Williams

2009 UNL Science & Math Technology Institute

A major factor in preventing accidents is stopping sight distance. This refers to how far ahead a driver can see and be able to bring the vehicle to a stop. There are two components in stopping sight distance, or SSD. One is how long it takes the vehicle to decelerate and stop, this is affected by the speed of the vehicle primarily. The other is how long it takes the driver to see the need to stop and actually apply the brakes.

The formula for safe stopping distance is given by:d = V2

2awhere d: deceleration distance in feet

V: vehicle speed in feet per seconda: 11.2 feet per square second, based on research

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