Car Movement. Or anything with speed!

First, Create a new flash document. Create a new symbol(Ctrl+F8) and name it car. For the behavior, select Movie clip. Click OK. Now draw a simple car. You can put more detail in later. Once you are done the car, click the blue arrow at the top to left of where it says scene 1. Now, place your car movie clip(Mc) out onto the stage. click on it. now click on the ACTIONS tab at the bottom. Copy this code there.

onClipEvent(load)
{
        speed =0 ;
}


onClipEvent (enterFrame) {
 // make the car go forward
 if (Key.isDown(Key.UP)) {
 speed += 1;
 }
 // make the car go backwards
 if (Key.isDown(Key.DOWN)) {
 speed -= 1;
 }

 // tells the car to slow down after the speed of 20
 if (Math.abs(speed)>20) {
 speed *= .7;
 }
 // you can change the rotation of the car to your desire
 if (Key.isDown(Key.LEFT)) {
 _rotation -= 15;
 }
 if (Key.isDown(Key.RIGHT)) {
 _rotation += 15;
 }
 // here is where the hittest is for the boundary
 speed *= .98;
 x = Math.sin(_rotation*(Math.PI/180))*speed;
 y = Math.cos(_rotation*(Math.PI/180))*speed*-1;
 if (!_root.land.hitTest(_x+x, _y+y, true)) {
 _x += x;
 _y += y;
 } else {
 speed *= -.6;
 }
}

Now test movie! you should be able to drive the car around. Now you want boundries? Draw any boundries you want and right-click on them and select COVERT TO SYMBOL... on the drop down menu. Now click on your boundies and at the bottom there is a properties tab. Click it. now, where it says instance name, type LAND in lowercase letters. This will make them boundries. Test your game! you shoud be able to drive and hit the boundries.