Photo courtesy OnStar Corporation
Being in a car accident is a nightmare -- you're often disoriented, upset and unsure of what to do once the actual crash is over. But if your car is equipped with GM's OnStar service, you don't even have to find your cell phone. The system can get help for you. It can also check your e-mail hands-free, make hotel reservations, and unlock your car if you've locked your keys inside, among other things.

OnStar is the most popular telematics service available in North America. As of May 2005, it had more than 4 million customers [ref]. But what is a telematics service? How does OnStar know where you are, and how can your car let the OnStar Call Center know that you've been in an accident? In this article, we'll explore the technology behind OnStar, find out how to use it, and learn about some of the controversy associated with it.