Throw Distance
Definition
The horizontal distance from the point of primary vehicle-pedestrian contact to the location where the pedestrian comes to rest. Combined with pedestrian height and surface friction, it is used in the Searle and related equations to back-calculate impact speed.
- Measured from
- Point of primary vehicle-pedestrian contact
- Measured to
- Where the pedestrian comes to rest
- Used with
- Pedestrian height and road-surface friction
- Application
- Back-calculating impact speed via Searle-type equations
Common questions
Why does the pedestrian's height matter for a throw-distance calculation?+
Taller pedestrians tend to be launched further for a given impact speed because of where the bumper or hood strikes relative to the body's centre of mass, so height is a correction term rather than a footnote in the formula.
What limits the accuracy of throw-distance speed estimates?+
The equations assume a fairly typical vehicle front-end shape, road surface and pedestrian posture at impact. Unusual vehicle geometry, a sloped or wet road, or a pedestrian who was crouching or turning can all push the estimate away from the actual impact speed.
Related terms
- Conspicuity
- The degree to which a pedestrian or cyclist is detectable against their background under the prevailing lighting conditions. It governs the detection...
- Fender Vault
- A variant in which the pedestrian contacts the vehicle's fender rather than the front face, resulting in a lateral throw to one...
- Head Wrap Distance (HWD)
- The distance along the vehicle's body surface from the primary contact point (usually the bumper) to where the pedestrian's head first contacts...
- Vault Impact Pattern
- A pedestrian impact sequence typical of high front-end vehicles (SUVs, trucks): the pedestrian is struck in the torso or pelvis, the body...
- Wrap Impact Pattern
- A pedestrian impact sequence typical of passenger cars and low-profile vehicles: the lower limbs are struck, the body rotates forward and upward...