How to Get light to bounce of floor Hello,

I want to make head lights for the car, I've put them in Layer 1, only the ground is on Layer 2, Layer 2 catches shadows from Layer 1, But doesn't catch light.
How do I make it so that Layer 2 Catches Light, whilst not making the whole Layer 2 brighter, so only the part where light is being pointed at it.
Your "Background" render layer has the lights on it, so all you need to do is some "Luminance" keying like so: