Car turorial reset vehicle

you can lock its rotation if it's a rigid body under rigidbody ~> constraints ~> freeze rotation.

Or

in your ResetCar function you can put a transform.rotation feature in there to reset it back to it's normal way up

Well assuming your car steers left and right around the Y axis, to reset its roll/pitch you need to reset only the X and Z axes.

On your car script, store the car's original rotation transform into a variable.

i.e

private float _originalRotX; private float _originalRotZ;

 void Start () {
     _originalRotX = transform.rotation.x;
     _originalRotZ = transform.rotation.z;
 }

 void ResetCar()
 {
         // Move the rigidbody up by 3 metres
         transform.Translate(0, 3, 0);
         // Reset the rotation to what it was when the car was initialized
         transform.rotation = (Quaternion.Euler(new Vector3(_originalRotX, transform.rotation.y, _originalRotZ)));
 }