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Tuesday, March 02, 2010

Brake-Throttle Override And Two Foot Driving

Amazing as it sounds, there are people who drive automatic transmission cars with two feet.  They typically drive with the left foot resting gently on the brake pedal, with the belief that they can brake more quickly than if they move their right foot from the gas to the brake.  They of course neglect the possibility that they will overlap, and will reduce the effectiveness of the brakes.

It is likely that NHTSA will mandate, or Congress will pass a law which requires that automakers who use Electronic Throttle Control Systems (ETC) must have brake override logic, similar to the software update that Toyota is releasing as part of its recent unintended acceleration recall.   

As this feature becomes more widespread, two-foot driving will become a little bit more difficult.  The two-foot driver will find that if they overlap brake and throttle pedal application, that they will get abrupt reduction in engine torque, and therefore more abrupt deceleration, as the ETC system slams the throttle closed to reduce engine power.  In order to drive smoothly, they will have to take the time to lift off of the throttle before pushing the brake, giving up much of the perceived advantage of two-foot driving.

6 comments:

Hames said...

I am vehemently opposed to this proposed regulation. On those rare occasions when I drive a vehicle with automatic transmission, I brake with the left foot. In performance driving, trailing braking while easing on the accelerator makes for smoother driving and more precise control of the tire's contact patch.

In addition, slushboxes often have an annoying takeup period as power is initially applied, and this can be mitigated by judicious brake application.

This is a typical overreaction by the government clowns who have to be seen to "do something" about a problem that may be serious but which occurs only rarely.

By the way, those few people who complain of runaway acceleration, why didn't they just depress the clutch pedal? Likely because safety begins with the driver, who was too lazy and incompetent to select a vehicle with manual transmission in the first place, and to drive it well.

Jason Lancaster said...

Hames - I'm sorry man but I have to laugh. I understand that maximizing the size of your tire's contact patch is critical on the race course, but there's no *^$(#@ way I'm worried about that when I'm stuck in traffic...not to mention the fact that most drivers (95%) simply have no concept of the concern you're addressing.

More to the point: automotive safety standards should not be reflective of the needs of enthusiasts. The goal isn't to create a country of race car drivers, it's to make the most dangerous activity most people engage in on a daily basis a little safer.

As for your question "why didn't they depress the clutch pedal," I've got some bad news: the clutch is dead sir. Unless you're buying a sports car or an economy cruiser, you're not going to find a stick shift. When was the last time you were in a showroom?? 1980? LOL :-)

chris... said...

I am 38 years old and have been driving with two feet ever since i started driving. Was it because my first car was a street-legal race car,and you had to keep one foot on the gas pedal just to keep it idling at a stop light??..I dont know but ive NEVER riddin the brake pedal...my foot actually hovers over the brake pedal or just to the side of it. I have NEVER been in an accident,knock on wood,...and have avoided many accidents because i was able to react so quickly,and hit the brakes.Ive heard some "one footers" say that if you drive with two feet,youll never be able to drive a stick....NONSENSE!!....ive drivin 5 speeds..6speeds..with amazing speed!!.....maybe natural born race car drivers are born to drive with both feet...i dont know......but it scares the crap outa me when i get in a car with someone,seeing only one foot controlling two pedals...and i watch how long it takes them to take their foot from the gas pedal to the brake pedal in a quick stop.....amazing!!.......i know for a fact it is safer to learn to drive with both feet....only makes sense to me.

Alexander said...

I've heard about this subject, ad nauseum. For this reason, I'm constantly aware, when driving, to keep my left foot above the brake pedal. When the left foot starts down the right foot comes up. Some years ago, a deer ran out in front of me and I managed to stop just short of it. It's not proof positive that the technique works but it's a pretty strong indication. My feeling is that, if you can be sure that you're not overlapping, it's a good technique. If not, then don't do it. It's an individual thing. As for the overlapping software, I don't think that I like it. A mechanic told me that, if your brakes get wey and "grab", you can cure this by driving slowly for a short distance with light pressure on the brakes. This will heat them up and dry them out. I've done this and it works.

carmudgeon said...

I'm with Hames and Chris on this one. I don't usually drive with 2 feet, though I'm trying to learn for autocrossing/track. But I do a whole lot of heel/toe (all of my downshifts, even on the street), and would conceivably desire to powerbrake my car. Also, I'd like to know that I can left foot in order to set the front end or jam the throttle and brake at the same time in order to straighten my car out should I end up sideways.

What it comes down to, as Hames said, is that people/the government think something needs to be done. I can see that, if you don't think like us, you wouldn't even know that a throttle override would cause any problems, so TO would be a wonderful thing. But since two-footing is important to a lot of people (SCCA, NASA, any other car organization), it shouldn't be considered.

That being said, VW (and others) have had it for years, but made in such a way that you can still do at least heel-toe and trailbraking

http://www.youtube.com/watch?v=HzY6kT0YSXQ&feature=related

Also, no one said that all cars should have fuel cells when Ford Pintos started blowing up. That would be an unreasonable reaction to a company totally screwing up a product. Same here.

Kobra said...

how bout a switch, or an override override. I only two foot if the vehicle is having engine issues, and need to nurse it home. this will not make life easier.