Second Player Car Movement

I want to make a 2 player car game, and I have one player, the buttons are up, down, left and right. I want the second player's buttons to be w, s , a, and d. How can I do this? This is the movement script, please change it so that the buttons I listed will be used for the same script.

onClipEvent (enterFrame) {

// This code will advance the car forward.

if (Key.isDown(Key.UP)) {

speed += .5;

}

// This will make the car go backwards

if (Key.isDown(Key.DOWN)) {

speed -= .5;

}

// The car will start to slow down after the speed of 10

if (Math.abs(speed)>5) {

speed *= .5;

}

// This will change the angle of the car

if (Key.isDown(Key.LEFT)) {

_rotation -= 4;

}

if (Key.isDown(Key.RIGHT)) {

_rotation += 4;

}

// 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;

}

}