Speed Decrease as a Function of Distance

[MSI]

Q: I'm looking for a graph of speed reduction per fractional-second to represent how much (or little) deceleration actually occurs during the first 0.5-sec to 1.0-sec. of braking.

A: That brings to mind a figure we created in our McHenry Accident Reconstruction 2008 book (currently out of print).
It does not include time, however it does provide a good illustration of the relationship between speed and distance that you can plug numbers into.
Please note that:

• In the first 30% of speed reduction, 50% of the total distance to rest is traveled.
• In 50% of the speed reduction, 75% of the total distance to rest is traveled.

A similar figure could be made for time.

speed decrease at constant decel.png