How do I make car wheels spin and slow down when the car is stopped

Hye,how do I make car wheels spin and slow down when the car is stopped? the car is automatically move forward and player is allow to control left and right button.

Example car game like SkidStorm [https://play.google.com/store/apps/details?id=com.immobilegames.skidstorm&hl=en]

I am using the car script from the Samuel 3D tutorial,Help is very much appreciated. Thank you

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class SimpleCarController : MonoBehaviour
 {
     //If you do not use center of mass the wheels base it off of the colliders
     //By using center of mass you can control where it is.
     public Transform t_CenterOfMass;
 
     //The maximum amount of power put out by each wheel.
     public float maxTorque = 500f;
 
     //The max distance a wheel can turn.
     public float maxSteerAngle = 45f;
 
     //Each wheel needs its own mesh
     public Transform[] wheelMesh = new Transform[4];
 
     //The physics of the wheels, max 20 axels.
     //WheelCollider[4] 4 is how many wheels we have.
     public WheelCollider[] wheelCollider = new WheelCollider[4];
 
     //Ridged body accessor.
     private Rigidbody r_Ridgedbody;
 
     public void Start()
     {
         // This sets where the center of mass is, if you look r_Ridgedbody."centerOfMass" is a function of ridged body.
         r_Ridgedbody = GetComponent<Rigidbody>();
         r_Ridgedbody.centerOfMass = t_CenterOfMass.localPosition;
     }
 
     public void Update()
     {
         //Sets the wheel meshs to match the rotation of the physics WheelCollider.
         UpdateMeshPosition();
     }
 
     public void FixedUpdate()
     {
         //Turn the wheels to a set max, with an input.
         float steer = Input.GetAxis("Horizontal") * maxSteerAngle;
         //Move forward or backwards based on the maxTorque, with an input.
         float torque = Input.GetAxis("Vertical") * maxTorque;
 
         //Sets which wheels turn, this is the two front wheels.
         wheelCollider[0].steerAngle = steer;
         wheelCollider[1].steerAngle = steer;
 
         //Sets which wheels move forward or backwards.
         for (int i = 0; i < 4; i++)
         {
             wheelCollider[i].motorTorque = torque;
         }
     }
 
     //Sets each wheel to move with the physics WheelColliders.
     public void UpdateMeshPosition()
     {
         for (int i = 0; i < 4; i++)
         {
             Quaternion quat;
             Vector3 pos;
 
             //Gets the current position of the physics WheelColliders.
             wheelCollider[i].GetWorldPose(out pos, out quat);
 
             ///Sets the mesh to match the position and rotation of the physics WheelColliders.
             wheelMesh[i].position = pos;
             wheelMesh[i].rotation = quat;
         }
     }
 }