Dear Car Talk:

I am teaching my nephew to drive. I have seen, over the years, that a number of teenagers have died from speeding in excess of 90 mph. I know that commercial trucks have speed inhibitors on them so they can't go over 65 mph. The companies also save on gas and speeding tickets, and get insurance breaks with these. For the life of me, I can't find something like that for my car (a Honda Civic). I don't want my nephew to drive in a car that can go over 65 mph. Where can I find such a device for my car?

-- John

Newer Fords have a feature called MyKey that allows the owner of the car to program a specific key. When that key is used, limits are set on the car's performance. So if you're in the market for a new car, that would be one solution. But unfortunately, kids can, and do, kill themselves going a lot slower than 65 mph.

An all-too-common tragedy involves a car full of kids, late at night, driving 50 mph on a curvy, dark road where the speed limit is 30, and there are sharp turns with speed limits of even less than that. Typically, the driver misjudges a turn at too high a speed and wraps the car around a tree. Then you have to watch weeping former classmates on TV the next day.

So instead, I think you need to get your nephew a nanny. Not a cute 17-year-old female nanny -- an electronic nanny.

There are a number of devices on the market these days that plug into the on-board diagnostic (OBD II) port of pretty much any car. They read data from the car's computer and record vehicle speed, hard acceleration, panic braking and other parameters that indicate that your kid has been driving like a knucklehead.

Some require you to take the device inside and plug it into your computer. Others will send you an email report once a day or once a week. Some will even text you when a set speed limit is exceeded.

The idea is not to spy on the kid secretly, but to let him know upfront that you're keeping a close eye on how he drives. Unless he's a complete dummy, if he knows that you'll find out if he goes 80 miles an hour or slams on the gas from a stoplight, he should be less likely to do those things.

If you search online for "teen driving monitors," you'll find a bunch of products, including those by MOTOsafety, CarCheckup, InTouch MVC and others.

But check with your car-insurance company first. Several insurers, including Travelers and Progressive, offer such devices, and they even offer discounts for people who use them.

And the fact that the insurance companies -- which we know hate to part with a penny -- will pay people to use these things is the best argument that they probably are effective. Good luck, John.