I know SFA stwert but I think thast what he needs. I thought along similar lines...a script that maybe has a random function in it. So car 1 = car 2 = etc etc and maybe another function as you say with different key frame points and frame speed if they need to be different speeds???
keep us posted?
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes