It's 61 miles an hour. Do you know where your kid is–and why he's driving so fast? With Safety Beacon, a GPS tracker offered for Safeco insurance customers, parents and young drivers can agree to rules of car usage, and a little black box rats them out if they don't follow the rules. It costs $15 a month per GPS-equipped vehicle and also includes OnStar-like features such as remote door unlock. According to Jim Havens, Safeco's VP of Consumer Solutions, early indicators (from beta test units) are that teens become better drivers with Safety Beacon, and transgressions quickly fall off.

The device can be set to report a speed higher than a limit agreed upon by parent and teen, and it can be changed online; but it's fixed, and therefore not relative to the posted limit. Other controls include usage beyond a prescribed area (geo-fence), and usage late at night or during the middle of a school day ("don't drive the car at lunch"). Schedules can be different for different days of the week and can be reset online by the parent.

The subscription includes 100 notifications (total, not per month), with extras running $30 per hundred. Many parents choose to send two notifications: one to the teen's cell phone so the teen knows there was a slipup, and one to the parent's e-mail address. "It's not meant to be punitive," Havens says. By the way, Havens adds, there's a 30-second window of forgiveness for the speed limit, say if you're passing another car. Parents can request the car's location at any time (that counts as a notification), but this isn't a breadcrumb-tracking device such as trucking companies use. For info, see the Teensurance Web site.

While Safeco believes Safety Beacon will make for better drivers, it's not lowering rates. No can do, Havens says: Lower rates, like raising rates, is typically the province of state insurance departments.