Tyre marks on the roadway are very helpful in determining vehicle behaviour and in many cases it is possible to estimate vehicle speeds based upon the length of skidmarks or radius of yawmarks.

Subject to proper investigation, the following charts provide preliminary advice as to vehicle speeds associated with skid distance or yawmark radius.

[Speed from Skidmark] – assumes skid to stop with no impact

[Speed from Yawmark] – assumes negligible vehicle yaw angle