Is it possible to get the (Current) Speed of a Vehicle Seat?

So with a Vehicle Seat, I want to get the variable(or property) that hold the seat's current speed and put it on a Surface GUI. However, I do not know where to find this variable or how to path it in a script. I assume this variable exists, as the ROBLOX built in speed GUI shows it (HeadsUpDisplay = true to see it). So is this possible? All answers appreciated, Thank You. ~Xduel