Calculate Speed from Skidmarks

Common question in traffic accident investigation and accident reconstruction are:

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    Can I calculate the initial speed given a skid length?
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    What distance is required to stop from this speed?

I decided to publish a simple tool to help you to “calculate speed from skidmarks “and “calculate stopping distance from speed

You will get an *answer simply entering the length of the skidmarks (a mark from a tire that is sliding without rotation), type of road surface and/or entering the speed and type of road surface in the calculator below.

The stopping distance or skid length with be displayed after you type/ select the desired value.

About the calculator

This calculator use the well known formula S=√254*f*d It is clearly not a skid to stop “universal tool”, the calculator does not take into account any road condition as the correct interpretation of the road evidence (skid, scrub , scuff marks, yaw marks), slope, drag factor, wear rate of ice or snow on the road surface.

If just “something else happens” during the skid to stop that can cause any speed loss due collision forces (impact ,etc.) , the time that the driver requires to identify, perceive and then react to a given hazardous situation.

Without question, the “speed from skid marks” and “stopping distance” calculator *may be used only as “rough approximation” for you information when a vehicle skids safely to a stop, without impact and/or without experiencing additional physical events at the end of the skid.

To discuss the above calculations, and any variables that might affect your specific case, please contact me as forensic traffic accident reconstructionist, I’ll be glad to assist you and answer your questions.

Time for Accident Investigation training?

I offer a variety of training opportunity in the field of accident investigation and accident reconstruction, for instance, during accident investigation training session we also cover the use and misuse of the skid to stop formula.

We have an extensive experience on training the accident investigation specialized team of Police department, if you want have more information about my accident reconstruction and accident investigation training experience you are welcome to ask  my CV and reference.