How do I control my HID's?

I recently installed HID's into my car off of a totalled Audi. The only problem is that it lights up the entire thurway, and I don't want to be an idiot and blind other drivers or cause an accidient. Is there a way to concentrate or focus the beam? Maybe using projectors, but I heard that they suck from other people. What can I do? Any input is great.