[Pottus]

How can you possibly verify that the distance your getting is accurate?
How is anyone supposed to know what all your values mean? Write out vehicles used and the results from each.
Where is your code so others can try and verify your results?
Where is comparisons against other systems to verify results?
Why calculate in miles per hour? GTA uses meters calculate for meters first then convert to miles and makes it a pain in the ass to compare results.

Please answer all these questions.

Also consider eliminating the need for SetVehicleVelocity() use only native top speeds.