how to display speed of a variable on screen

we want to display the speed of a variable on screen(e.g. i have a car and i want to display its speed on the screen),can anybody help please?

I used the onscreentext from panda to display some little info on screen

from direct.gui.OnscreenText import OnscreenText
self.textObject = OnscreenText(text = " ", pos = (-0.95, 0.95), scale = 0.07,fg=(1,1,1,1))

Hoping usefull.

thnks shimrod very very much, :smiley: