Want to know where your teen is? Ask OnStar

OnStar will roll out its GPS tracking service to customers starting April for $3.99 per month.

OnStar Family Link Web site shows your car's location.

If you're nervous about giving your teen driver the keys to the family car, you may be able to buy peace of mind from OnStar. The telematics company now offers the ability to tell you where your vehicles, and possibly the drivers, are at any time.

Family Link is an optional add-on service to the operator assisted emergency response and navigation services offered by OnStar. Subscribers can log on to OnStar's Family Link Web site to view a map with the vehicle's location at any time. They can also schedule email or text alerts to update them periodically on the location of the automobile on specific days or times.

The company completed beta testing of its FamilyLink product last year, and will make this service available to all OnStar customers in phases starting in April. The service will be available to all customers by the end of the year. Subscribers can add this service for $3.99 to any OnStar plan. It's not clear if this service will be available with the aftermarket product, OnStar For My Vehicle.

The GPS technology is already used by law enforcement to help them locate stolen vehicles, and now OnStar is giving its customer base the same tool without needing to file a police report.

"Last year, we had more than 4,500 subscribers test the Family Link service and they told us it provides them peace of mind by staying connected to their family when they're on the road," said OnStar Vice President of Subscriber Services Joanne Finnorn.

The service will make it easier for parents to keep an eye on young or elderly drivers. Of course, the technology could also be misused. Last year a man was rumored to have caught his wifecheating on him using the "Find My Friends" app. It wouldn't too hard to imagine that suspicious or jealous spouses may be able to sign up surreptitiously for the service and use it to spy on their partners. But privacy, on top of the $3.99 monthly fee, seems to be the price to pay for more sophisticated safety and convenience technology.