Speed ​​car at the start of the game

I have a script.

 /*
 Script Created by FlatTutorials for "Car Controller kit".
 */
 
 @script AddComponentMenu ("FlatTutorials/Scripts/Car Control Script")
 #pragma strict
 var centerOfMass : Vector3;    //Center of mass
 var dataWheel : WheelCollider;    //Wheel Collider from which you want to calculate the speed
 var lowestSteerAtSpeed : float = 50;    //if lowestSteerAtSpeed < currentSpeed the steer Angle = highSpeedSteerAngel
 var lowSpeedSteerAngel : float = 10;    //This could be a high value
 var highSpeedSteerAngel : float = 1;    //This shouldn't be a high value (recomended for stability of car)
 var decellarationSpeed : float = 30;    //How fast the car will decellarate
 var maxTorque : float  = 50;    //Maximum Torque
 var currentSpeed : float;        //Current Speed of car
 var topSpeed : float = 150;        //Highest speed at which the car can go
 var maxReverseSpeed : float = 50;     //Highest Reverse speed
 var backLightObject : GameObject;    //Mesh for reverse light
 var idleLightMaterial : Material;    //for idle state
 var brakeLightMaterial : Material;     //Braked state
 var reverseLightMaterial : Material;    //Reverse state
 @HideInInspector    
 var braked : boolean = false;    //Brake trigger
 var maxBrakeTorque : float = 100;     //Braking speed
 var speedOMeterDial : Texture2D;    //GUI Texture for dial
 var speedOMeterPointer : Texture2D;        //GUI Texture for needle
 var gearRatio : int[];        //Shift gear at speed
 
 
 function Start () {
 rigidbody.centerOfMass=centerOfMass; //Center of mass , for this the car should be pointing on z axis
 }
 
 function FixedUpdate () {
 HandBrake();
 }
 function Update(){
 BackLight ();
 EngineSound();
 CalculateSpeed();
 }
 
 //Speed Calculation
 
 function CalculateSpeed(){
 currentSpeed = 2*22/7*dataWheel.radius*dataWheel.rpm*60/1000;
 currentSpeed = Mathf.Round(currentSpeed);
 }
 
 //Light Control
 
 function BackLight (){
 if (currentSpeed > 0 && Input.GetAxis("Vertical")<0&&!braked){
 backLightObject.renderer.material = brakeLightMaterial;
 }
 else if (currentSpeed < 0 && Input.GetAxis("Vertical")>0&&!braked){
 backLightObject.renderer.material = brakeLightMaterial;
 }
 else if (currentSpeed < 0 && Input.GetAxis("Vertical")<0&&!braked){
 backLightObject.renderer.material = reverseLightMaterial;
 }
 else if (!braked){
 backLightObject.renderer.material = idleLightMaterial;
 }
 }
 
 //Brake Trigger
 
 function HandBrake(){
 if (Input.GetButton("Jump")){
 braked = true;
 }
 else{
 braked = false;
 }
 }
 
 //Engine Sound
 
 function EngineSound(){
 for (var i = 0; i < gearRatio.length; i++){
 if(gearRatio[i]> currentSpeed){
 break;
 }
 }
 var gearMinValue : float = 0.00;
 var gearMaxValue : float = 0.00;
 if (i == 0){
 gearMinValue = 0;
 }
 else {
 gearMinValue = gearRatio[i-1];
 }
 gearMaxValue = gearRatio[i];
 var enginePitch : float = ((currentSpeed - gearMinValue)/(gearMaxValue - gearMinValue))+1;
 audio.pitch = enginePitch;
 }
 
 //Speedometer
 
 function OnGUI (){
 GUI.DrawTexture(Rect(Screen.width - 300,Screen.height - 150,300,150),speedOMeterDial);
 var speedFactor : float = currentSpeed / topSpeed;
 var rotationAngle : float;
 if (currentSpeed >= 0){
   rotationAngle = Mathf.Lerp(0,180,speedFactor);
   }
   else {
   rotationAngle = Mathf.Lerp(0,180,-speedFactor);
   }
 GUIUtility.RotateAroundPivot(rotationAngle,Vector2(Screen.width - 150 ,Screen.height));
 GUI.DrawTexture(Rect(Screen.width - 300,Screen.height - 150,300,300),speedOMeterPointer);
 
 }
 

How to make a car when you turn on the game itself went forward? Start game = auto speed 100. How to do it?