Flash Game + Collision of two cars

I am new to actionscript, and am trying to get a collision between two cars,  I have the movement of the cars working, and am trying to detect if they collide, I would then like to have the cars react to the collision.  Here is what i have so far, i am not getting any values going into the collisiondetection function.  Please help.

This is what i have so far

StageWidth = 600;
StageHeight = 400;
function moveCar1() {
      // Make the starting position of the car
      this._x = this.x=0;
      this._y = this.y=0;
      // Velocity of car
      this.xvelocity = this.yvelocity=0;
      // Tire Speed
      this.tspeed = 0;
      // Angle of car
      this.angle = 0;
      // The friction acting on the tires from the ground
      this.tfriction = .15;
      // This determines the angle that the car is steering
      this.steering = 0;
      this.onEnterFrame = function() {
            // This determines what these variables do
            keyLeft = Key.isDown(Key.LEFT);
            keyRight = Key.isDown(Key.RIGHT);
            //the reason why these two are not capitilized any is because "keyUp" and"keyDown" are commands in flash
            keyup = Key.isDown(Key.UP);
            keydown = Key.isDown(Key.DOWN);
            // By pushing on certain keys, you get acceleration and decceleration
            if (keyup) {
                  this.tspeed += 1;
            }
            if (keydown) {
                  this.tspeed -= 1.5;
                  if (this.tspeed<-7.5) {
                        this.tspeed = -7.5;
                  }
            }
            // Friction from ground; this can be any small number so that the car doesn't keep going
            // if a key isn't pressed
            this.tspeed *= .90;
            // Velocity Change
            idealxvelocity = this.tspeed*Math.cos(this.angle*Math.PI/180);
            idealyvelocity = this.tspeed*Math.sin(this.angle*Math.PI/180);
            // By taking the difference between the current velocity and ideal velocity,
            // you get the actual velocity
            // When you apply the friction, you get the actual velocities.
            this.xvelocity += ((idealxvelocity-this.xvelocity)*this.tfriction);
            this.yvelocity += ((idealyvelocity-this.yvelocity)*this.tfriction);
            // By adding the velocities, you can get the new x and y positions
            this.x += this.xvelocity;
            this.y += this.yvelocity;
            // By pushing the Left and Right keys, the car steers in that direction
            if (keyLeft || keyRight) {
                  this.steering += (keyRight-keyLeft);
            } else {
                  // When you let go of the Left and Right keys, the car goes back to going straight
                  this.steering += ((this.steering<0)-(this.steering>0));
            }
            // You want to make sure that when you steer that it doesn't start turning faster and faster
            if (this.steering<-10) {
                  this.steering = -10;
            }
            if (this.steering>10) {
                  this.steering = 10;
            }
            // Now you can make the car turn based on actual speed and turning angle
            actualSpeed = Math.sqrt((this.xvelocity*this.xvelocity)+(this.yvelocity*this.yvelocity));
            this.angle += ((this.steering*actualSpeed)*.15);
            this._angle = (this.angle+360)%360-180;
            
            // Hit outside
            if (this.x>=StageWidth) {
                  trace("Hit Wall");            
            }
            
            if (this.x<0) {
                  trace("Hit Wall");      
            }
            //if (this.x<=10) {
                  //this.x = 10;
            //}
            if (this.y>=StageHeight) {
                  trace("Hit Wall");
            }
            
            if (this.y<0) {
                  trace("Hit Wall");
            }
            
            //if (this.y<=-10) {
                  //this.y = -10;
            //}
            // You need to update the angles from radians to degrees so that it can turn
            this._rotation = this.angle+90;
            this._x = this.x;
            this._y = this.y;
            
      };
}

function moveCar2() {
      // Make the starting position of the car
      this._x = this.x=0;
      this._y = this.y=50;
      // Velocity of car
      this.xvelocity = this.yvelocity=0;
      // Tire Speed
      this.tspeed = 0;
      // Angle of car
      this.angle = 0;
      // The friction acting on the tires from the ground
      this.tfriction = .15;
      // This determines the angle that the car is steering
      this.steering = 0;
      this.onEnterFrame = function() {
            // This determines what these variables do
            keyLeft2 = Key.isDown(65);
            keyRight2 = Key.isDown(68);
            //the reason why these two are not capitilized any is because "keyUp" and"keyDown" are commands in flash
            keyup2 = Key.isDown(87);
            keydown2 = Key.isDown(83);
            // By pushing on certain keys, you get acceleration and decceleration
            if (keyup2) {
                  this.tspeed += 1;
            }
            if (keydown2) {
                  this.tspeed -= 1.5;
                  if (this.tspeed<-7.5) {
                        this.tspeed = -7.5;
                  }
            }
            // Friction from ground; this can be any small number so that the car doesn't keep going
            // if a key isn't pressed
            this.tspeed *= .90;
            // Velocity Change
            idealxvelocity = this.tspeed*Math.cos(this.angle*Math.PI/180);
            idealyvelocity = this.tspeed*Math.sin(this.angle*Math.PI/180);
            // By taking the difference between the current velocity and ideal velocity,
            // you get the actual velocity
            // When you apply the friction, you get the actual velocities.
            this.xvelocity += ((idealxvelocity-this.xvelocity)*this.tfriction);
            this.yvelocity += ((idealyvelocity-this.yvelocity)*this.tfriction);
            // By adding the velocities, you can get the new x and y positions
            this.x += this.xvelocity;
            this.y += this.yvelocity;
            // By pushing the Left and Right keys, the car steers in that direction
            if (keyLeft2 || keyRight2) {
                  this.steering += (keyRight2-keyLeft2);
            } else {
                  // When you let go of the Left and Right keys, the car goes back to going straight
                  this.steering += ((this.steering<0)-(this.steering>0));
            }
            // You want to make sure that when you steer that it doesn't start turning faster and faster
            if (this.steering<-10) {
                  this.steering = -10;
            }
            if (this.steering>10) {
                  this.steering = 10;
            }
            // Now you can make the car turn based on actual speed and turning angle
            actualSpeed = Math.sqrt((this.xvelocity*this.xvelocity)+(this.yvelocity*this.yvelocity));
            this.angle += ((this.steering*actualSpeed)*.15);
            this._angle = (this.angle+360)%360-180;
            
            if (this.x>=StageWidth) {
                  this.x = StageWidth;
            }
            if (this.x<=5) {
                  this.x = 5;
            }
            if (this.y>=StageHeight) {
                  this.y = StageHeight;
            }
            if (this.y<=-10) {
                  this.y = -10;
            }
            
            // You need to update the angles from radians to degrees so that it can turn
            this._rotation = this.angle+90;
            this._x = this.x;
            this._y = this.y;
      };

}

function carTocarDetection(b1, b2) {
      //set the speed variables
      var xmov1 = b1.xmov;
      var ymov1 = b1.ymov;
      var xmov2 = b2.xmov;
      var ymov2 = b2.ymov;
      
      trace(xmov1)
      trace(xmov2)
      trace(ymov1)
      trace(ymov2)
      //set the position variables
      var xl1 = b1.xpos;
      var yl1 = b1.ypos;
      var xl2 = b2.xpos;
      var yl2 = b2.ypos;
      //define the constants
      var R = b1.radius+b2.radius;
      var a = -2*xmov1*xmov2+xmov1*xmov1+xmov2*xmov2;
      var b = -2*xl1*xmov2-2*xl2*xmov1+2*xl1*xmov1+2*xl2*xmov2;
      var c = -2*xl1*xl2+xl1*xl1+xl2*xl2;
      var d = -2*ymov1*ymov2+ymov1*ymov1+ymov2*ymov2;
      var e = -2*yl1*ymov2-2*yl2*ymov1+2*yl1*ymov1+2*yl2*ymov2;
      var f = -2*yl1*yl2+yl1*yl1+yl2*yl2;
      var g = a+d;
      var h = b+e;
      var k = c+f-R*R;
      //solve the quadratic equation
      var sqRoot = Math.sqrt(h*h-4*g*k);
      var t1 = (-h+sqRoot)/(2*g);
      var t2 = (-h-sqRoot)/(2*g);
      if (t1>0 && t1<=1) {
            var whatTime = t1;
            var carsCollided = true;
      }
      if (t2>0 && t2<=1) {
            if (whatTime == null || t2<t1) {
                  var whatTime = t2;
                  var carsCollided = true;
            }
      }
      if (carsCollided) {
            trace("Cars Collided");
            //Collision has happened, so throw a trace
            //car2carReaction(b1, b2, xl1, xl2, yl1, yl2, whatTime);
      }else{
            trace("No Collision")
      }      
}


car1.onEnterFrame = moveCar1;
car2.onEnterFrame = moveCar2;

this.onEnterFrame = function() {
      carTocarDetection(game.car1, game.car2);
}