Stop my car from bouncing like a rubber band ball

Ok so I already did a search for this problem and followed several sets of instructions none of which worked. Whenever my car lands on any surface from a high distance, or with a lot of velocity it winds up bouncing ridiculously. Currently right now both the car, and the object I am bouncing it on is made out of a bounceless material with the following properties:

Additionally the giant cardboard box I am bouncing this one has the following script attached to it: using UnityEngine; using System.Collections;

 public class killBounce : MonoBehaviour {
     
     void OnCollisionEnter(Collision collision){ //set y velocity of collider to 0 and stop the annoying gamebreaking bouncing
         Debug.Log("Killbounce activated");
         var currentVelocity = collision.rigidbody.velocity;
         
         currentVelocity.y = 0f;
 
         collision.rigidbody.velocity = currentVelocity;
         Debug.Log (collision.rigidbody.velocity.y);
     }
     
 }

But alas it is to no avail. The car still bounces like a kickball on a trampoline. What can I do to fix this?