Is a "dynamic stability control" system worth the money?

Dear Car Talk

Dear Car Talk | Jan 01, 2005

Dear Tom and Ray:

My husband and I recently moved from Connecticut to Colorado, and are considering buying a new car. We have a 2000 BMW 528i, which I have loved, but because we are now in a place with a lot more snow and in a county with a lot of dirt and gravel roads, it doesn't really fit our needs anymore. Neither of us wants a sport utility vehicle, but we have been considering the Subaru Outback Wagon. My question: The vehicle dynamics control is only available on the most expensive model. Is that system worth the extra cost? My husband is suspicious of any system that claims to take over for the driver -- probably because when he was younger, he raced cars, and he likes to feel as if he always has control -- but I will be the main driver of the car, and I'm a normal driver. Is it worth it? Thanks so much. -- Dee

TOM: The short answer is yes. It IS worth it. More and more studies are showing that dynamic stability control (often referred to by a confusing array of acronyms like VDC, DSC, ESP, MSPCA, etc.) does do a lot to help people avoid accidents.

RAY: Dynamic stability control is one of the newest electronic forms of skid control. These systems work by using sensors to detect signs of a skid, and then limiting acceleration and applying the brakes on individual wheels to regain control of the car.

TOM: Why do you want to prevent a skid? Well, once you're skidding -- once the tires are no longer in full contact with the road -- it's very hard to control the car. You're much more likely to plow into something, be it another car, a tree or a mango-smoothie stand by the side of the road.

RAY: These days, the three major anti-skid systems are: ABS, or antilock-brake systems, which help you avoid skidding when you're making an emergency stop; TCS, or traction control, which helps you avoid skids while you accelerate; and DSC (or whatever each manufacturer happens to call its version of dynamic stability control), which helps you avoid skids while you're moving and turning. DSC helps prevent you from losing control of the car when you take a corner too fast or swerve to avoid something. And it works.

TOM: So, if it's available -- and sadly, Subaru only makes it available on the top-of-the-line Outback -- we'd recommend it.

RAY: Your husband -- like most guys who take his position -- is wrong. Sure, we all want to be "in control." But the fact is that microcomputers can handle certain tasks better than even the most skilled driver ever could. The computer that controls these systems can pulse an individual wheel's brake 10 or 15 times per second. A human driver could never do that.

TOM: Of course, most cars with stability control have a switch that allows you to turn it off. So, if your husband is determined to have control, he can turn off the system, make some high-speed swerves and crash your new car into a chicken coop to prove our point.

RAY: But dynamic stability control is something we DO recommend, when it's available. And we hope it will be available on more cars and SUVs as time goes by (Ford just announced that it's putting it on all its SUVs in 2005, and Chevy is putting it on its full-size SUVs and vans).

TOM: By the way, Dee, the Subaru Outback is a very nice car. But since you love your BMW, you might also consider the BMW 325xi. It's smaller than your current 528i, but it comes with all-wheel-drive and dynamic stability control.

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