Get color pixel from terrain, with a WheelCollider!

Hello,
how i can get the color pixel, from a point in the texture terrain? But the point, need do the point that a wheel collider, collided with the terrain.

For sample, I have a car, and your wheels. I did a simple dust emitter in your wheels, and I want to the particles, that get out from emitter, have the color of texture that the wheel collided on terrain.

I know that I can use the Raycast, bui I can’t associate this funtion to solve this.

Thanks

Hmm something like that?

function OnCollisionEnter(collision : Collision) {
    // Debug-draw all contact points and normals
    for (var contact : ContactPoint in collision.contacts) {
        Debug.DrawRay(contact.point, contact.normal, Color.white);
    }