race car waypoint

hi..
i making race car game..

i put planes to set waypoints, example, on the start of the track, there is a plane, like portal...

when the car collision with that plane, the clock start to runing....

but, if i use collisions, the car crash with the plane...

how can i do, to make a collision witouth affect the movement of the car...?

Use a proxy object parented to the car, and check for collisions with that.

:) good idea... thanks!!