Unintentional acceleration

Having spent many years of my youth working on my own cars in the 60’s, and being the son of a mechanic, who always insisted things be done right, I have a fundamental observation on brakes

and unintended acceleration.

My dad remarked about high powered cars, that no matter the power of the car, if the brake system was working properly, the

brakes will overpower the engine. And he demonstrated this briefly from a standing start, and while moving, with one foot on the accelerator and one on the brake. Not a practice for general use, but just to make a point.

During the Audi events of old, similar to today’s Toyota problems, he always believed that it was driver error, due to the pedal arrangement in those vehicles being odd to U.S. drivers.

Now he is not around to comment on the current issue, but I’m curious what those out there think? Won’t properly functioning brakes stop an accelerating car, and, in a standard transmission vehicle, stall the engine? Thanks, Joe

Car and Driver magazine recently tested three cars (Camry V6, Infinity G37, and Roush Stage 3 Mustang), and in all three the brakes could stop the car even when the throttle was wide open.

The Roush Mustang makes 540 hp, and the brakes still stopped it, although it took a LONG time.

This test was done without shifting to neutral, which would have shortened the stopping distances.

If the car is already going at a high rate of speed and the engine is at full throttle, then the brakes are likely to overheat and fail before stopping the car. A test was done on one of the Lexus models, and the result was that they couldn’t stop the car.

I agree with you and your Dad. It’s also frequently mentioned as the first step in stopping a car with runaway acceleration. But since we are all human and subject to errors while driving, the best cureis not having unintended acceleration occur in the first place.

your dad was right, adequate brakes should overpower the car. If the manufacturer doesnt provide adequate brakes, its the manufacturers fault.

Brakes might be able to handle a situation like this, but they only get one chance. And they’d better be cool when you start trying.

If someone is deliberately trying to stop to zero, and not just get their speed to where it was before, and they had not been doing any braking shortly before, they’ve got a chance. If they dick around trying to slow it down rather than stop it, by the time they get the hint that they need to stop, the brakes will be closer to overheating, and they’ll be screwed.

That’s probably why when my dad had it happen in his 82 Monte Carlo (dealer error installing hand controls), he couldn’t get it under 50 miles per hour (in a residential neighborhood!) without shutting the engine off.

In the Car and Driver test, they knew exactly what they were doing, and they knew what their goal was. A real unintended acceleration situation would probably be more complicated.

Oh, and the Roush is probably intended to be able to do burnouts. You don’t want the engine to stop when the brakes are applied.

I’m curious. Does the Roush Mustang have big ol’ Brembos with oversize carbon fiber discs (not the pads, the discs themselves)?

Don’t know if that Roush had the Brembos, but it was a manual tranny, so just pushing in the clutch would also have solved the problem, but they just wanted to see. I guess another problem with ‘just hit the brakes’ is that some folks pump the brakes, depleting the boost at wide open throttle, then their goose is cooked. Unless, of course, they just shift to neutral.

So the owner of a Prius is screwed then, right? :stuck_out_tongue:

This whole accelerator-getting-stuck business makes me wonder if there has ever been a problem with the cruise control (on any make/model) getting stuck? If that were to occur, I assume you should do the same … put it in neutral?

I dont understand what your trying to say. are you insulting me, or toyota? I am saying that good brakes should stop the car no matter what.

and my grandfather owns a prius. nice interior in them.

It was a jab at the problems some Prius owners are having with their brakes. The use of the “:P” should have indicated it was a joke in the first place.


Hitting the brakes turns cruise control off. It it doesn’t, then yes, neutral and brakes combined and you are stopping. In manual cars with cruise control, hitting the clutch also turns off the cruise.

Your dad may have been right, but a car’s brakes will stop it in far shorter a distance if it’s shifted into neutral and not fighting the engine.

Your dad probably also made the comment in a time where “high powered” cars were much less powerful than they are now (comment applies to stock vehicles only). 250+ HP probably wasn’t common in family sedans back then, and 400HP was probably very rare.

I agree with your dad that most of these unintended acceleration problems were in the past driver error, but I truely believe this one is pure design error.

We are told: "Simply put the car into neutral then turn the engine off."
MAY NOT BE SO SIMPLE! Check out these video clips:

(after putting car in neutral and unable to turn off engine!!!)



and the CA crash:
“911 Call Released from Crash that Prompted Initial Toyota/Lexus Floor Mat Recall”
(with California Highway Patrolman driving unable to stop vehicle)

"Witnesses saw flames coming from the front and rear tires of the speeding 2009 Lexus ES 350 before it crashed Aug. 28 in Santee, suggesting ?long, constant heavy braking,? said Sgt. Scott Hill, the lead sheriff’s investigator. "

"Toyota Recalls Spur Worries"