General Motors’ OnStar unit has unveiled a pilot program that will allow parents to track the real-time location of their teenagers when they are driving. Vehicles can be tracked by logging on to a GM website to view a map with the vehicle’s exact location at any time or by getting text messages or email alerts. About 10,000 active U.S. OnStar subscribers will be invited to take part in the pilot program with the focus on GM owners who are parents with teen drivers. Other pilot programs are also under consideration.