[Extremo]

Alternatively, you could look into the following functions:

GetPlayerVelocity
SetPlayerVelocity

However this would most certainly require a loop and thus may not be desirable because of performance related issues. Up to you.

EDIT:

Speaking of which, you probably should make sure to detect the EXACT speed of sprinting, because I am unaware if car surfing or other sorts of movement are considered velocity.