[ODE] Driving boxes on the arc or curve.

[Jon Watte (ODE)]

Tim Sorrells wrote:
> Your acceleration force should be based on the car's known mass and the distance to the car in front of it.

Actually, you usually get better behavior if you also take the relative 
velocity into account. Measure the velocities of the cars, and add some 
force proportional to the difference (and the mass) as well.

Cheers,

          / h+