how to cause to character contorller to rotate when it collide the wall?

Currently I'm developing a game with cars. I'm using character controller because I want to use characterController.simpleMove and because I want to use the characterController stairs feature.

i want that when the car will collide the wall it will turn in a way that the angle between the normal and the car before the collide will be equal to the angle between the normal and the car after the collide:

I succeed to write code that do it with rays:

 void OnCollisionEnter(Collision collision) {
         RaycastHit hit;
         if (Physics.Raycast(transform.position, collision.contacts[0].point, out hit ,100 , bumpers))
         {
             if (debug)
             {
                 Debug.DrawRay(hit.point,hit.normal * 20 ,Color.blue,1);
                 Debug.DrawRay (hit.point,transform.forward * (-20) , Color.magenta,1);
                 Debug.DrawRay (hit.point, ((20 * hit.normal) - ((-20) *transform.forward )) , Color.red,1); 
             }            
         }
     }
 
 
 
      void Start () 
     {
         bumpers = LayerMask.GetMask ("bumpers");
     }
 

this is how it looks when I put the context of OnCollisionEnter method in update method:

its work too when I put the code only in the OnCollisionEnter at the clash time.