Then - suddenly, and entirely on its own - the car began straightening out. Mr. Ollie could feel the car gently apply the brakes and pivot back onto its original course. "I did nothing," says Mr. Ollie, an e-commerce consultant. "The car just recovered."

After years of promises from manufacturers, those high-tech gizmos that are supposed to revolutionize the automobile are finally hitting the showrooms. In the coming months, new vehicles will come equipped with everything from night vision to Internet access to radars that regulate distance from other cars. Unlike the gadgets of the past, which focused on less-glamorous functions such as exhaust systems and odometer readings, these are designed to ease the hassles and risks of driving itself. In short, they are the first real step toward the "smart car," which the industry has long touted as the vehicle of the future.

But do any of these gadgets actually work? To separate the truly useful from the merely neat and the not-ready-for-prime-time, Weekend Journal went on some test drives. In all, we looked at eight of the newest technologies and assigned each one a "usefulness" rating (on a scale of one star to five), plus a "wow factor," since - face it - many of these gizmos are just high-tech toys, anyway.

In general, we found some of the sexiest gadgets to be the least useful, such as GM's and Lincoln's relatively primitive Web access and Jaguar's voice-control system, which lets you bark commands at your radio and air conditioning. Less exotic features, such as the stability-control system in Mr. Ollie's Volvo, typically seemed more helpful.

Eventually, manufacturers envision a car that practically does the driving for you - guiding drivers through traffic jams and around trouble spots, while bathing them in a sea of information and entertainment from the Internet. For now, though, it's a good idea to keep your eyes on the road. Here is our gadget guide:

Night Vision
Available on: Cadillac DeVille Cost: $1,995
Wow factor: *****
Usefulness: ***

Think Superman. This feature, adapted from military equipment, uses an infrared camera to help drivers see things far beyond the headlights' glow. It projects an image of the road ahead on a small patch of windshield just above the wipers. Other cars, animals and pedestrians are visible from the heat they emit.

The ghostlike images can be mesmerizing. But there is just one tiny problem: Other than on dark, two-lane roads, we didn't find it to be much help in driving. The system doesn't show signs, traffic lights or anything else that is the same temperature as its surroundings. Rain and snow also can make the image fuzzier. In fact, on lighted roads we generally found the infrared image to be a distraction. "If you're in the city or in heavy traffic, you don't need it," says Alex Itkin of Bloomfield Hills, Mich., who has night vision in his new DeVille. "But at night, in poor visibility, you suddenly can see everything." Indeed, Mr. Itkin credits night vision with helping him avert a potential collision with several deer crossing a dark Ohio highway last month.

Voice Control
Available on: Jaguar S-type sedan, some Cadillac models this fall
Cost: $4,300 on Jaguar (includes navigation system, car phone, telematics)
Wow factor: ***
Usefulness: **

Feel like no one listens to you? Soon, at least your car will - with a feature that is already available on Jaguar's S-type sedan. It lets drivers verbally instruct the car to control the radio, telephone and internal temperature. Press a button on the steering wheel and the stereo mutes, the fan goes quiet and a display under the speedometer says, "listening," signifying that your electronic servant is ready. Say "temperature 67" ad the system sets the climate control. "Tune 101.9" sets the radio (it knows it is an FM station.) Over the next few years, voice activation will be the key to Web access and all sorts of other auto features, so get used to talking to your car. But for the moment, it isn't much better than traditional buttons and knobs. When we showed it to friends, the general response was "that's neat, but why?"

Telematics
Available on: Some GM, Mercedes, Lincoln, Infiniti and Jaguar models
Cost: Standard on some vehicles; $600-$1,500 on other models, plus $15-$40 per month for service
Wow factor: ****
Usefulness: ****

Feeling lonely? Press a button, and you will have someone to talk to. This system provides emergency and, for an extra charge, concierge service on the road. Unlike the existing navigation systems on luxury cars, this technology links your car though an onboard cell phone to a 24-hour service center whose operators know exactly where you are thanks to global-positioning equipment.

The main appeal of telematics, which is expected to be standard equipment in several years, is safety. If you have an accident or the car breaks down, you can summon help from an operator. If the wreck is severe enough to trigger the air bags, the system automatically sends a distress signal. GM's Onstar system, which is already available on a limited basis and widely touted in TV ads, will even give your basic medical information to emergency crews.

Most auto makers believe consumers will want only the basic service. But GM is betting some will pay an extra $200 a month for more pampering. When we sought a caffeine fix on a drive through northern Indiana, for example, the system found us a nearby cafe and even recommended a doughnut shop on the way.

Stability control
Available on: Most luxury cars, plus high-end Toyota and Oldsmobile sedans
Cost: $500-$1,000 as an option
Wow factor: **
Usefulness: *****

This is the feature that prevented Boston's Mr. Ollie from hitting the snowbank. We tried it out on almost a dozen cars - and it proved quite effective. With the system disengaged, a swerve from dry pavement onto sheer ice sent the car into a spin. When we turned it on, the car steered off the ice and onto the road smoothly.

In the snow, the system kept cars from fishtailing, even at high speed. Rear-wheel-drive models, not normally adept at winter handling, became easy to maneuver. Even the Chevrolet Corvette performed well in the snow; with the system turned off, it was all but uncontrollable. The system also helps prevent wipeouts on dry pavement. One problem: If you steer into the skid - the way they taught in drivers' ed - the car can get confused and react abruptly.

Of course, using this feature is likely to inspire more terror in your friends than awe. That certainly cuts into the wow factor, though after skidding a few times we found the "relief" factor to be quite high.

Adjustable Pedals
Available on: Ford Expedition, Taurus, Lincoln Navigator, Mercury Sable
Cost: Standard on some large SUVs; $120 option on other models
Wow factor: *
Usefulness: *****

Here is one for the it's-about-time file: How often have you gone through countless adjustments on a car seat without finding a truly comfortable fit? It happens all the time, especially to shorter drivers who have trouble reaching the pedals. The popularity of giant sport-utility vehicles has made the problem even more common.

Ford Motor Co. began offering electrically adjustable pedals as an option on models such as Ford Expedition and Lincoln Navigator SUVs. Now, it is also on family cars such as the Taurus. It may not make you say "wow," but it is arguably the most practical of the new crop of features.

Web on Wheels
Available on: About 30 GM models and several Lincolns this fall
Cost: Some systems standard; others expected to be about $2,000 for hardware (including navigation system), plus $10-$20 a month for service
Wow factor: *****
Usefulness: ***

Gentlemen, start your e-ngines. Later this year, you can go online on the road.

We tested an early prototype, which is due out this fall as an added feature on GM's Onstar system. Press a button and say "Start Onstar" and the system uses a cellular phone link to dial into the server. You can then verbally request weather, news, sports, traffic or e-mail - which a computerized voice will read you.

Cadillac will soon offer a more elaborate system that, instead of relying on a computer elsewhere, actually replaces the radio with an in-car PC. Log in, and your PC will download e-mail (and, eventually, Web sites) and read you the content. The PC will have a small screen, but for safety reasons most text will be visible only when the car is in park.

While the concept is impressive, the jury is still out on practicality. For example, none of them currently allow you to send e-mails. Eventually, Cadillac's system will let you choose among several pre-programmed reply options or record a voice message to send back. But for now, the range of options is fairly limited. Reliability will vary with the quality of local cellular-telephone coverage.

Autopilot
Available on: Mercedes S-class and CL models this fall
Cost: Expected to be around $2,000
Wow factor: *
Usefulness: **

Imagine a world where, instead of keeping your feet on the pedals, you can lean back and relax. This system, which Mercedes and Jaguar already offer on top-of-the-line models in Europe, is the first step in that direction. A very small step. The system uses radar to keep the car a safe distance from the vehicle ahead. When we tried a Mercedes test car in reasonably light traffic, it worked well, allowing us to set the cruise control and drive for stretches of more than an hour without touching the pedals. Just the ticket when the car's other computer is in the middle of reading you a long e-mail.

But there were some hair-raising moments on more congested roads - like when the computer failed to notice a slow-moving tractor-trailer in the lane ahead. (A decidedly low-tech foot on the brake saved the day.) Nor did it immediately recognize stopped traffic ahead on the interstate. Mercedes says it will get the bugs out before the system is released in the U.S. this fall, adding that the European version needed to be adjusted more than expected to suit American driving patterns.