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A car that drives itself?

A car that drives itself? 'Smart' cruise control technology brings the futuristic dream one step closer to reality.

Published July 29, 2011

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Cars that drive themselves without driver input have been the dream of futurists and science-fiction writers for almost as long as the car has existed. Finally, bit-by-bit, that dream is being realized.

Last fall, an experimental Audi TTS, developed jointly by the Volkswagen Group, Stanford University and Oracle, made history by completing the infamous Pikes Peak hill climb without a driver — albeit in twice the time of the fastest human-guided vehicles.

It will be some time before all the technologies encompassed by that rolling laboratory make it into production vehicles. But several that count as stepping-stones toward that end are already available.

More: New car option designed for distracted drivers

More: Google unveils its self-driving car

Among the most relevant is “smart” cruise control, also known as adaptive cruise control (ACC) and by several brand-specific names.

Automatic vehicle speed control has been the subject of experimentation since at least 1910, and commercial cruise control systems have been available in new cars since the late 1950s.

Their purpose is to maintain a constant vehicle speed, uphill and down, regardless of terrain or conditions.

A cruise control system is a relatively simple device in principle. It automatically opens or closes the engine’s throttle based on feedback from speed sensors to maintain the pre-set speed.

Initially the control and feedback components of the system were mechanical but they are now electronic.

Adaptive cruise control adds to that basic function by maintaining a preestablished distance behind the vehicle ahead, if it is travelling below the chosen speed.

Typically, the ACC system emits either a radar or laser beam from the front of the vehicle and measures the time for it to bounce back. It then converts that measurement into a distance measurement, taking into account the vehicle’s own speed.

The vehicle speed is then adjusted to maintain the minimum pre-set distance.

Most vehicles equipped with ACC allow the driver to select the minimum distance setting, usually from three options — typically equating to a one- to three-second spacing from the car ahead.

Such systems first became available in the late 1990s. While they performed their primary functions, they were not totally glitch free.

I recall driving a vehicle with one of those early systems in relatively light traffic on Highway 401. While it did slow me down as I approached a slower vehicle directly ahead, it also did so when I caught up to a tractor-trailer rig in an adjacent lane, periodically making my car a rolling roadblock until I switched off the system.

Some others I’ve encountered worked erratically, if at all, in rain or snow conditions.

A week spent recently in an Infiniti M Hybrid demonstrated just how much the systems have improved in a little more than a decade.

I used the system extensively, even in conditions where I normally wouldn’t engage cruise control, hoping to find a flaw in its operation. I found none.

There were no false slowdowns. And the slowdowns that did occur were so smoothly implemented they were indiscernible. I would be driving along at 100 km/h only to realize, without noticing, that I had slowed down to 90.

Pull over one lane, out from directly behind the car ahead, and the Infiniti accelerates smoothly back to 100, no muss, no fuss.

You may think such a system promotes driver laziness, and I admit it could. But I submit it is just as likely to offset driver laziness.

I know I should keep a distance of at least two seconds behind vehicles ahead — and I consciously work at it. But occasionally I find I’m within a second or less without even realizing it and have to make a quick adjustment.

No such problem with adaptive cruise control. It keeps me honest, and smooth.

There’s another side benefit, too. According to a study on the origin of traffic jams by University of Michigan Professor L.C. Davis, a “spectacular” reduction in single-lane jams could result if just 20 per cent of the vehicles in a 600-car platoon were equipped with adaptive cruise control.

It’s a good first step.

wheels@thestar.ca

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