The Barrier impact angle equation is used to determine the approximate maximum angle of a vehicle departure from the road for a given lateral distance.
The ability of a vehicle to change its direction of motion is dependent upon its forward speed, the utilized roadway friction and the lateral space available for the maneuver. Thus, it is possible, for example, to approximate the maximum angle of vehicle motion at the point of contact with a highway guardrail for a given combination of travel speed, highway width and the tire-pavement friction.
- See our 2003 McHenry Accident Reconstruction write-up on the Barrier Impact Angle Equation
- From our 1987 SAE paper HVOSM-87 we include the figure below.