Carcamera script raycasting fail ?

Can anyone point out why the Unity car tutorial carcamera raycasting fails please ?

 using UnityEngine;
 using System.Collections;
 
 public class CarCamera : MonoBehaviour
 {
     public Transform target = null;
     public float height = 1f;
     public float positionDamping = 3f;
     public float velocityDamping = 3;
     public float distance = 50f;
     public LayerMask ignoreLayers = -1;
 
     private RaycastHit hit = new RaycastHit();
 
     private Vector3 prevVelocity = Vector3.zero;
     private LayerMask raycastLayers = -1;
     
     private Vector3 currentVelocity = Vector3.zero;
     
     void Start()
     {
         raycastLayers = ~ignoreLayers;
     }
 
     void FixedUpdate()
     {
         currentVelocity = Vector3.Lerp(prevVelocity, target.root.rigidbody.velocity, velocityDamping * Time.deltaTime);
         currentVelocity.y = 0;
         prevVelocity = currentVelocity;
     }
     
     void LateUpdate()
     {
         float speedFactor = Mathf.Clamp01(target.root.rigidbody.velocity.magnitude / 170.0f);
         camera.fieldOfView = Mathf.Lerp(55, 72, speedFactor);
         float currentDistance = Mathf.Lerp(45.5f, 6.5f, speedFactor);
         
         currentVelocity = currentVelocity.normalized;
         
         Vector3 newTargetPosition = target.position + Vector3.up * height;
         Vector3 newPosition = newTargetPosition - (currentVelocity * currentDistance);
         newPosition.y = newTargetPosition.y;
         
         Vector3 targetDirection = newPosition - newTargetPosition;
         if(Physics.Raycast(newTargetPosition, targetDirection, out hit, currentDistance, raycastLayers))
             newPosition = hit.point;
         
         transform.position = newPosition;
         transform.LookAt(newTargetPosition);
                 
         
         }
 }

I am wondering why the raycasting doesn't stop the camera going through the terrain or other objects on this script ,anyone have any ideas ,I presume because its the Unity car tut it works for everyone else ,I have been stuck with the same issue for months now no matter what camera scripts I try ,please can anyone tell me whats wrong as I dont want to have to make all race tracks flat lol.