/**** 
* Classes
****/ 
// Bus class
var Bus = Container.expand(function () {
	var self = Container.call(this);
	var busGraphics = self.attachAsset('bus', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 3;
	self.update = function () {
		self.y += self.speed;
		if (self.y > 2732) {
			self.destroy();
		}
	};
});
// Assets will be automatically created and loaded during gameplay
// Car class
var Car = Container.expand(function () {
	var self = Container.call(this);
	var carGraphics = self.attachAsset('car', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 5;
	self.update = function () {
		self.y += self.speed;
		if (self.y > 2732) {
			self.destroy();
		}
	};
});
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerGraphics = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.lane = 2;
	self.lives = 3;
	self.moveLeft = function () {
		if (self.lane > 1) {
			self.lane--;
			self.x = self.lane * 512 - 256;
		}
	};
	self.moveRight = function () {
		if (self.lane < 4) {
			self.lane++;
			self.x = self.lane * 512 - 256;
		}
	};
	self.loseLife = function () {
		self.lives--;
		livesTxt.setText('Lives: ' + self.lives);
		if (self.lives <= 0) {
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		}
	};
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000000 // Init game with black background
});

/**** 
* Game Code
****/ 
var player = game.addChild(new Player());
player.x = 1024;
player.y = 2400;
var cars = [];
var buses = [];
var score = 0;
var scoreTxt = new Text2('0', {
	size: 150,
	fill: "#ffffff"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
var livesTxt = new Text2('Lives: 3', {
	size: 100,
	fill: "#ffffff"
});
livesTxt.anchor.set(0.5, 0);
LK.gui.topRight.addChild(livesTxt);
function spawnVehicle() {
	var lane = Math.floor(Math.random() * 4) + 1;
	var vehicle;
	if (Math.random() < 0.5) {
		vehicle = new Car();
		cars.push(vehicle);
	} else {
		vehicle = new Bus();
		buses.push(vehicle);
	}
	vehicle.x = lane * 512 - 256;
	vehicle.y = -100;
	game.addChild(vehicle);
}
game.down = function (x, y, obj) {
	if (x < 1024) {
		player.moveLeft();
	} else {
		player.moveRight();
	}
};
game.update = function () {
	for (var i = cars.length - 1; i >= 0; i--) {
		if (cars[i].intersects(player)) {
			player.loseLife();
		}
		cars[i].update();
	}
	for (var j = buses.length - 1; j >= 0; j--) {
		if (buses[j].intersects(player)) {
			player.loseLife();
		}
		buses[j].update();
	}
	if (LK.ticks % 60 == 0) {
		spawnVehicle();
		score++;
		scoreTxt.setText(score);
	}
};

===================================================================
--- original.js
+++ change.js
@@ -43,15 +43,15 @@
 	self.lives = 3;
 	self.moveLeft = function () {
 		if (self.lane > 1) {
 			self.lane--;
-			self.x -= 512;
+			self.x = self.lane * 512 - 256;
 		}
 	};
 	self.moveRight = function () {
 		if (self.lane < 4) {
 			self.lane++;
-			self.x += 512;
+			self.x = self.lane * 512 - 256;
 		}
 	};
 	self.loseLife = function () {
 		self.lives--;