www.craftanimations.com, in Part 1 of this turbo tutorial on Craft 4-Wheeler Extended you will learn how to rig and animate a sports car through physics simulations inside of XSI, cinema4d, 3ds max or Maya, with Craft Director Studio. At the end of this part the autonomous mode is exemplified by automatically letting the car follow a spline path (path constraing in 3ds max, or motion path in maya). For velocity controlled spline animation you should check out the Craft Spline Speed-Controller - Turbo Tutorial, it's a killer tool for any vehicle animator, as well as for Camera animators.