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Think you can out-drive a computer? You can't

If you want to die in a car, driving flat out in the rain is one way to get your wish.

I am doing about 200 km/h in a downpour that has turned the Mont Tremblant race track into a skating rink. As the end of the back straightaway approaches, raindrops blast the windshield of my BMW M3 like millions of silver bullets, and a hairpin curve looms ahead.

The physics are intimidating. The M3 has 414 horsepower. The track's surface friction is a fraction of what it would be in the dry. And I am covering approximately 55 metres every second: If I miss the upcoming corner, I will hit a concrete wall.

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But I have a secret weapon. Buried within the M3's sleek shape is a collection of sensors that would do justice to a jet fighter: tiny accelerometers are measuring the car's speed and slip angles, then feeding the information into onboard computers that help prevent a crash. It's known as electronic stability control (ESC). And, at this particular moment, I'm liking it more and more.

As I brake and turn into the hairpin, the system is working each of the M3's four brakes individually, like a team of tiny, digitized Michael Schumachers. At the entry to the corner, I'm still doing more than 100 km/h, and the M3 slides sideways, pushed toward the edge of the track by centrifugal force. I can feel the tail end trying to snap around, but the ESC counteracts the impending spin, applying a touch of brake to the outside front wheel, and perhaps a little to the inside rear wheel as well, subtly tweaking the M3's angle.

It works. I slide through the corner, clip the edge of the track and accelerate away in a contrail of atomized water. And so it goes. Lap after lap, the M3 and its brilliant electronics carry me through. At day's end, the car and I roll into the pits unscathed. The age of the digital driver has arrived - if you want to go fast these days, Bill Gates is your co-pilot.

Although some drivers scoff at ESC, they are looking more and more like vehicular Luddites. Formula One drivers use ESC in their street rides, and if it weren't for the rules, they'd have it in their race cars, too. ESC can do things that humans can't, and it has made converts of even the most skilled drivers in the world. "From a safety point of view, it's an incredible system," says Danny Kok, chief instructor for the Mercedes Benz Driving Academy. "I think it should be in every car."

Although ESC has become best known in high-performance vehicles like BMW, Mercedes and Porsche, it is now filtering down into the world of everyday driving. Starting next September, Transport Canada will require that every new car sold in this country be equipped with ESC. The rationale is safety. In 2006, for example, 768 Canadians died in crashes involving loss of control, and 2,578 more were seriously injured. Transport Canada says 225 of those deaths (and 755 of the injuries) would have been eliminated by ESC.

No one needs to preach the benefits of ESC to Dave Empringham, a racing driver with a résumé that includes multiple Formula car championships and a 24 Hours of Daytona win. "The really good systems are like the difference between Senna and the average driver," Empringham says. "To me, it's a no-brainer - anyone who doesn't want this in their car is an idiot."

Not long ago, Empringham had a near-death experience when a driver he was coaching in a Porsche at Mosport raceway turned off the ESC system without telling him. Heading into the track's notorious Turn Two, a high-speed left hander that falls away downhill, the Porsche's back end slid sideways, snapping the car into a spin that ended with a high-speed impact into a concrete retaining wall.

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Until he learned that the driver had turned off the ESC, Empringham was confused. "The system would have caught the slide," he said. "That's what I expected. Obviously, that's not what happened."

As I've learned during multiple lapping sessions at Mosport, the physics and psychology of Turn Two can be intimidating. You approach the corner over a blind crest at up to 200 km/h, then dive downhill in a long left turn that makes the car go light due to the elevation change.

I've driven it in a long series of cars, including the Porsche 911 Turbo and the Mercedes C63 AMG, both equipped with spectacularly good ESC systems. The experience made me give thanks to the wise software and chassis engineers who made this possible. "It helps you out," says Empringham. "Even if you're a good driver."

ESC systems were pioneered in the late 1980s by Mercedes Benz and BMW, and have advanced steadily since then. At first, the idea of a digital system that could help control a car seemed implausible - and it was seen as an insult to human drivers.

"Ego is the single biggest obstacle," says Kok, who insists that students leave ESC switched on while participating in the Mercedes Academy. "A lot of drivers think they can out-drive a computer. But they can't."

Empringham agrees. As he sees it, ESC does what an expert driver would, but with a speed and subtlety no human can match. "All we can do is push on the brake pedal," he points out. "We can't control each wheel separately."

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As Empringham learned in his coaching-session crash at Mosport, humans often react incorrectly. When the Porsche started going sideways in Turn Two, the driver could have saved the situation by quickly steering into the slide and holding the throttle steady. But the driver reacted too late - by the time he applied steering correction, the slide was already well developed. Then the driver compounded the error by taking his foot off the accelerator, an instinctive reaction that shifted the car's centre of mass forward, accelerating the spin.

Empringham still thinks about that day. Up until the moment when the Porsche spun out of control, he had no concerns - as he saw it, the situation was well under control. If he had been at the wheel himself, he would have made a quick correction, and all would have been well. But he wasn't. And the system that could have taken his place had been disabled. So now he has a new rule: "When I'm in the car, the system is on," he says. "That's just the way it is."

Auto maintenance expert explains why this is a job for the repair shop

How ESC works

Electronic stability control uses a collection of digital sensors and computer modules to do what highly skilled drivers would love to be able to do: sense the start of a slide, then correct it by controlling each wheel individually.

The most sophisticated ESC systems monitor the speed of each wheel, as well as a car's movements in every direction, including roll and yaw (sideways movement). When a slide is detected, the system tries to straighten out the car by applying differential brake force to the appropriate wheels. Some systems also control the throttle.

If a driver encounters a patch of ice while cornering on a highway on-ramp, for example, an ESC system will detect the slide, or rotational movement, then apply the brakes in the correct sequence to straighten the car, while avoiding throttle movements that could exacerbate the situation.

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About the Author
National driving columnist

Peter Cheney launched his driving column after 25 years as an award-winning feature writer, investigative reporter and news correspondent. His writing steers clear of industry jargon to focus on human experience and the passion of driving. More

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