Calculating Vehicle Speed from Yaw Mark Analysis

More information

Main author

Stephen Cash; Mark Crouch

Co-Authors

-

Type of media

PDF

Publication type

Lecture

Publication year

2015

Publisher

24. EVU Conference, Edinburgh

Citation

-

edinburg2015 21bInvestigating a crash where a vehicle has left curved tyre marks is a relatively common occurrence for a Collision Investigator. Much research surrounding the subject has provided criteria that once met, allows a vehicle’s speed to be calculated. This paper examines the validity of conventional principles, and presents an alternative approach that can be used in many collisions where current criteria may not be satisfied. This paper outlines, from basic principles, the current methodology of calculating a vehicle’s speed from a curved tyre mark and goes on to examine the forces introduced by vehicle yaw and braking. By understanding centripetal motion, 'critical speed', and braked and rotating vehicles, it then provides an expression to calculate vehicle speed where the range is both narrow and stable, with a narrower error band than conventional methods.

edinburg2015 21a

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