Dear Tom and Ray: I'm a concerned mom. Our spirited 16-year-old daughter will soon have her driver's license. We subscribe to the Reaganesque philosophy of "trust but verify" when it comes to raising teenagers. Is there a covert car-tracking device or service that you recommend that would provide us with the ability to locate the vehicle on demand via e-mail or SMS (Short Message Service)? Thanks for your help!

-- Blair

TOM: Spirited. Gotcha. Yes, there are such devices. But I would encourage you to go overt rather than covert.

RAY: Right. The idea is not to "catch" your little juvenile delinquent driving 80 mph through a school zone; the idea is to teach her not to do that. There are several devices on the market that provide feedback to the driver in real time, in addition to tattling.

TOM: One we particularly like is called tiwi. It's a global positioning system-based computer that costs about 200 dollars. You also pay a monthly subscription fee of about $40. But what it allows you to do is set your own rules. So if you decide that your daughter is allowed to go only 5 mph over the speed limit, the unit will alert her when she's broken that rule, and also will alert you immediately -- by phone, e-mail or text message.

RAY: By giving her instant feedback ("You're going over the speed limit, and we're calling your mother"), she's given a strong incentive to start following the rules.

TOM: There are other "black box" or EDR (event data recorder) devices, and you can find many of them on the Internet. They can monitor speed, hard braking and hard acceleration. Some provide instant feedback to the driver and reporting to a parent; others just collect the data and offer it to you via a website at your convenience.

RAY: But the cool thing about tiwi is that, because it's one of the GPS-based systems, it knows the speed limit of whatever road she's on at that moment. Other devices just allow you to set a maximum speed of, say, 75 mph. But you can kill a lot of people driving 74 mph in a 35-mph zone.

TOM: Tiwi also allows you to set "no go" zones with the GPS so that it will let you know when, for example, your daughter leaves the immediate area. Or wanders into her boyfriend's neighborhood.

RAY: She's going to hate this thing, Blair! It is intrusive. But the stakes are so high in the case of a new teen driver (life and death) that some parents may decide that the invasion of privacy is worth it, at least for the first few years of driving.

TOM: And after a few years, the hope is that your daughter will have developed safe driving habits, and will be mature enough to make good driving decisions on her own. And if not, there's always the convent!