Wheel Collider steering problem

hi … im using wheel collider for car …but when i steer the car flip this may script;

    var motorPower:float = 20;
var steerPower:float = 20;
var backWheel1:WheelCollider;
var backWheel2:WheelCollider;
var frontWheel1:WheelCollider;
var frontWheel2:WheelCollider;
    var vs :float;
    var hs :float;
    function Start(){
    
    motorPower = 300;
    steerPower = 50;
    
    }
    function Update(){
    
    vs = Input.GetAxis("Vertical")* motorPower;
    hs=Input.GetAxis("Horizontal")*steerPower;
    
    backWheel1.motorTorque = vs;
    backWheel2.motorTorque = vs;
    
    frontWheel1.steerAngle = hs;
    frontWheel2.steerAngle = hs;

Try lowering the center of mass of your vehicle’s rigidbody.

Add anti roll bars.