Unintended Acceleration

Unintended Acceleration

Don't step on the gas unless you mean it

News Item: A woman, who was driving a neighbor's car, crashed into her own house, through the kitchen, out the back, across the yard, through the fence, across the alley and into a ditch. "It accelerated and the brakes wouldn't work," she said.

Been There. Done that.

Well, sort of. Similar to that unfortunate driver, I have pushed the wrong pedal-more than once. It can happen to anyone. The only difference is that prior to my incident, I'd practiced corrective actions, so it didn't end expensively.

Instead of pushing the gas when I wanted the brake, I got the clutch instead of the brake. Also, several times I've been a riding instructor in high-performance driving events when students pushed the gas in the mistaken-but unshakable-belief they were on the brake. And, I witnessed an accident where a car accelerated wildly from a stop into another vehicle and then a telephone pole: Her brake lights never illuminated. I've experienced my share of unintended acceleration, which is also known as sudden or unanticipated acceleration, or pedal misapplication.

In a modern, properly maintained passenger vehicle, the brakes easily overpower the engine.

Don't fret that your car might develop a mind of its own and accelerate wildly despite your best efforts to stop it: In a modern, properly maintained passenger vehicle, the brakes easily overpower the engine. I've proven this in hundreds of vehicles, from Corollas to Corvettes. Try it yourself. In an empty parking lot, bring your properly maintained automatic-transmission vehicle to a stop. Place your left foot hard on the brake. While holding the brake to the floor, push the accelerator all the way down. Have no fear: Your car will not move. Unintended acceleration complaints fell dramatically when carmakers installed brake/transmission inter-locks, devices that require the driver to push the brake pedal before automatic transmission cars can be shifted out of Park.

Double Entendre

But what if the car is already in motion? Return to that deserted parking lot or find an empty dead-end road. Make certain there's no traffic behind. Get up to, say, 30 mph. then plant the accelerator to the floor with your right foot. Simultaneously push aggressively on the brake with your left. Now, stay hard on both pedals until the car comes to a stop. Stopping distance will be longer than if the throttle wasn't wide open, but stop you will.

Certainly, accelerators can stick open for a number of reasons: Misplaced floor mats, a broken engine mount, and an improperly installed racecar throttle cable have allowed me to experience the fright of stuck throttles. There's another cause: Drivers mistakenly pushing the gas instead of the brake. It can happen to anyone, but my experience says it's more common if you're driving an unfamiliar vehicle. Being stressed, fatigued, or distracted are also contributing factors. Also, braking systems can fail, but I've never seen or heard of one that healed itself. The common thread in unintended acceleration accidents is the fact that the driver swears he was pushing on the brake pedal for all his might, but the braking system worked perfectly immediately after the accident.

Here's a pedal misapplication mea culpa. After a long day of performance testing vehicles for a car magazine, I was headed home in one of the subject cars. I was exhausted and dehydrated. To slow for a freeway interchange I went for the brake with my left foot. (Like the vast majority of race drivers, I brake with my left foot at least some of the time.) A shot of adrenaline went through my body when the pedal went straight to the floor. My racing experience kicked in and I pumped the pedal in an effort to offset what I incorrectly assessed was a loss of hydraulic pressure. (I also disparaged the other test driver's heritage for not telling me he'd burned out the brakes.) After three rapid, but fruitless, cycles of the pedal, I came to the embarrassing assessment: This was the manual-transmission variant of the vehicle, not the automatic. (We had tested both that day.) I was pushing the clutch, not the brake. I moved over to the middle pedal. That did a lot better job of slowing the car.

Foot in Mouth

Twice I've been a ride-along instructor in performance driving events when drivers made identical errors. Here's one: Coming into a hairpin corner on the student's first lap, I sensed the car wasn't slowing adequately, so I instructed: "Brake." The car exhibited little slowing. In such a pressure situation, some students' minds are about as quick as a 1986 Tandy 1000 computer, so I shouted: "Slow down! Stop! Push on the brake!" The student yelled back "I AM!" ('I am' WHAT? I wanted to shout.) But the car continued rolling along. We bounced off the road and into the grass. We weren't accelerating but we weren't slowing much either. Suspecting the cause of the problem, I looked down at his left leg. His foot was firmly planted on the clutch. "You're pushing the clutch," said I. The driver initially denied it but then looked down before he admitted that he was pushing the wrong pedal. Sometimes this pedal misapplication works the other way: The driver pounds the brake when he really wants the clutch. This is an unwelcome surprise for not only the driver and passengers, but for anyone following close behind. (Racers learning to left-foot brake are susceptible to this error.)

Far more common, panicked drivers plant the gas instead of the brake. I don't watch every driver's feet (I'm susceptible to motion sickness), but I've seen enough to know that a large percentage initially push the gas to the floor. Yet, when I say, "Brake!" they correctly switch over to the brake.

During another high-performance driving event, I had a long argument with a driver, a graduate of the biggest racing school, over which pedal she was pushing. As she lost control and the car spun out, I slipped the transmission into neutral: Pedal misapplication is far from uncommon in these events. (They don't pay me enough.) The exchange went like this: Me: "Brake." Driver: "I AM braking." Background noise: Engine screaming at top rpm. "You're on the gas." "No, I'm braking!" Background noise: Engine bouncing against its rev limiter. The car came to rest and I said, "Get off the gas." "I'm not on the gas!" she insisted. "Hear the engine-" "Oh."

Driving Tips

How can you avoid becoming a victim of unintended acceleration? First, do the simple stuff. Check the pedal placement any time you drive a new (to you) car. Make sure floormats are properly fitted and there are no loose items that could block the brake pedal. Avoid overly wide or heavy footwear to prevent simultaneously pressing gas and brake. (When I am required to wear steel-toe shoes, I make certain I avoid collecting both gas and brake.) Get all the way in the car before moving it, and insist that parking lot valets and car wash attendants do so when moving your car. If you notice the throttle sticking, the cruise control acting up, the shift interlock isn't working, or the brakes are aging, get the car to a mechanic immediately.

Next, prepare for the unexpected. Humans rarely do the correct thing when they face emergencies for which they haven't prepared. In fact, they react a lot like deer blinded by headlights. If you don't practice the proper procedure, you're unlikely take effective action. Think about what you'd do if your car began to accelerate unexpectedly. Develop a race-driver mentality: If "A" doesn't work, try "B." If "B" fails, try "C." if "C" doesn't help, try "D." Race drivers don't give up until well after all hope is lost.

If the car is accelerating and you believe you're pressing on the brake, release the pedal you're pushing, move your foot to the left and try again. If that doesn't work, press the brake with both feet: It's difficult to get both feet on the accelerator. Try pumping the brake pedal in an effort to develop brake pressure. If you hear the engine sound rising and falling as you pump, check again for the pedal to its left. If it's a manual-transmission car, try braking with your right foot.

Next, practice moving the shift lever to neutral: In some cars (especially automatics with a center-mounted shifter) it's very easy to slap it into Neutral. Some manufacturers' design prevents the selection of Reverse or Park without pressing a button. Other configurations (especially column-mounted shifters) make it more difficult select Neutral: Try it in your vehicle. In manual transmission-equipped cars, press the clutch at the first hint of unintended acceleration. In both cases, modern engine-speed (a.k.a. rev) limiters will prevent motor damage. (While you're doing this make triple certain you're pushing the brake and only the brake.)

If none of this works, switch the ignition off. Most recent cars prevent you from locking the steering without putting the car in Park. Practice while motionless and then again at very low speed before an emergency. If all else fails, pull (or press) the emergency brake. Passengers in unintended acceleration emergencies can also act fruitfully: Slip the shifter into neutral, switch off the ignition, yank the parking brake.

Whoa, Nellie

With the aging of the population, expect incidents of unintended acceleration to increase. Several studies have shown that older drivers are many times more likely to be involved in such incidents. Since I personally am suddenly accelerating toward 60, I expect pedal misapplication will continue to be part of my life.

Allow me to finish with a story related to me by my old-time driver instructors: The student was learning to drive relatively late in life. Progress was being made. But then the new driver encountered an unexpected obstacle. Rather than pushing the brake pedal, the driver did what was natural to him and what he'd practiced all his life: He shouted "Whoa. Whoa. Whoa." and pulled back on the steering wheel as if he were pulling his mules' reins. While the farmer's animals would have responded to those commands, the Ford Model A he was learning to drive didn't and he wound up in the ditch. It was among the first cases of pedal misapplication.

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