You mean the parking brake? It’s not going to stop you any better than the regular braking system. The only “emergency” the parking brake would come in handy for is a total failure of both circuits of your brake’s hydraulic system. And on most cars, it’s not really separate from the regular braking system-- it just uses a cable instead of hydraulics to actuate the regular rear braking surfaces (or a dinky little separate one on some rear-disc setups).
In quite a few recent cars, the computer won’t let you over-rev the engine. You’ll get to redline or 500 RPM below, and it’ll hold you back.
My '02 Sable had a redline above 6000 RPM, but it wouldn’t let you go above 4000 RPM in neutral.
It would take substantial time to blow your engine like that, certainly more than enough to stop from any speed a passenger car could do.
I’d be very surprised if that Lexus didn’t have a rev limiter. And really, when the alternative is crashing at 100mph who cares if you blow up the engine over-revving it?
I’ve actually experienced a stuck throttle once, albeit in a rather different vehicle - 81 VW Rabbit diesel, which was about as electronic as a slide rule. The floor mat had somehow scrunched itself up in such a way that it grabbed the accelerator, and when I pushed in the clutch to shift from 2nd to 3rd the engine just took off. Very disconcerting. Let out the clutch in 3rd, realized the throttle was stuck, pushed in the clutch, turned off the engine, pulled over and stopped. So, no real drama, but it was extremely disconcerting and there were a few seconds of Oh Shit what do I do now before my brain re-engaged.
If you want an excellent explanation of fly-by-wire and its application to modern airplane design and control, i highly recommend this article, from a recent edition of Vanity Fair, about the landing of US Airways flight 1549 on the Hudson river.
It’s written by William Langewiesche, who is a former airline pilot himself, and is also an outstanding journalist and writer.
If you don’t want to read the whole thing, click forward to page 6 for the fly-by-wire stuff.
One thing to remember here, as many have already said - it was an unfamiliar vehicle travelling at over 100 miles an hour. The driver, even a trained driver, is not really in a position to be entirely rational.
Further, thinking on it, someone with Saylor’s (supposed) skill may be able to use some form of controlled skid / slide to bleed off speed - but remember that with a stuck throttle that speeds going to come back again pretty fast.
I don’t know anything about the Prius, but our Audi has keyless start, and I don’t think this scenario is all that likely. First of all, it knows the difference between the key being inside the car and the key being nearby. You can open the door without the key in the car, but you can’t start it. If I even step a foot outside the car to get the mail out of the mailbox (with the key in my hand to open the mailbox), it starts complaining. I’m sure it’s theoretically possible to have the key near enough to trick it into thinking it’s inside, but in my experience it’s not likely to happen by accident. Secondly, the moment the running car realizes the key is no longer inside (or is no longer within range in your situation), it starts beeping and showing a key/question mark icon on the dashboard. It’s very hard to ignore. Even if I were able to start the car without the key inside the car, it would be going off before I got to the end of the driveway.
At least with the car I have, it would be extremely hard to drive off without the key and not know about it immediately…
A co-worker of mine had a similar situation when she borrowed her brother’s Mercedes. She dropped him off at work and then left for her work. Unfortunately, her brother kept the key fob in his pocket. The car functioned normally until she came to a stop at a red light, when it died and would not re-start.
So at least for that model, the fob going out of range didn’t cause the vehicle to die while in motion, likely for safety reasons.
It was a 2009 Lexus ES 350.
But it dosen’t look like the problem is specific to that particular model, the recall list includes.
2007-2010 model year Toyota Camry
2005-2010 Toyota Avalon
2004-2009 Toyota Prius
2005-2010 Tacoma
2007-2010 Toyota Tundra
2007-2010 Lexus ES350
2006-2010 Lexus IS250 and IS350
Toyota tried to claim this week that their vehicles have no defects and got slammed by safety regulators.
Toyota is blaming the floor mats. That is stupid. One of the persons in an accident did not have floor mats.
Yeah. When I was learning to drive, I drove from one end of Golden Gate Park to the other with that brake on. I noticed because of the smell, not because of any resistance to acceleration.
This is true on every vehicle I’ve ever owned.
My husband and I both separately experienced run-away throttle on our Ford Ranger (yes, we’ve fixed it) due to a problem with the actual physical cable between pedal and throttle. In both instances we shifted the automatic transmission into neutral (yes, the engine does makes noises), hit the emergency flashes, and coasted to the side of the road. Yes, it was alarming but nobody got hurt and nothing got broke. I don’t entirely understand the panic caused by this situation, but I fully acknowledge I may not be typical of most drivers. Frankly, I didn’t give a [expletive deleted] about whether or not I’d trash the engine - it’s more important that my personal self not get hurt than whether or not I have to replace an inanimate object. Seriously, human beings are more important than a car or pickup or SUV or whatever.
My car - a Toyota, as it happens - is surprisingly low-tech for its model year, having a minimum of electric crap on it (manual crank windows, manual doors, etc.) and requires a key to start. In the event of run-away throttle/stuck accelerator I’d shift it to neutral. If I couldn’t, I’d shut down the engine - you can’t withdraw the key unless it’s in park but you can turn off the engine and you won’t lock the steering (yes, I have tried this!). While mechanical linkages do have their share of problems in many ways I trust them more than “drive by wire”.
Yes, airliners and military jets are “fly by wire” - they are also fantastically expensive per unit and have a MUCH higher quality control than the vast majority of cars. You know, for the small airplanes I fly I also prefer mechanical links for many things, too. Among other things, I can look at a mechanical item and sometimes detect problems with my eyeballs (hence, my motivation to preflight a small airplane) whereas I can’t see electrical defects.
Full activation or partial?
Was this a Plymouth Roadrunner with a 426 under the hood, or a Ford Escort?
On my current vehicle full activation at speed will in fact lock up both rear wheels and start a slide.
Your current vehicle is probably front wheel drive, whereas I’m guessing the vehicle in question was an old rear-wheel drive jalopie of some sort. On a RWD car, the torque of the engine fights with the parking brake and drags the brake shoe against the drum. If you’re driving an automatic, the torque converter is quite good at allowing even a small engine to send enough torque to the back brake to move the car, possibly without even noticing anything amiss.
On the other hand with a FWD car, the torque to turn the back wheels comes from the road, so the back tires can pretty easily lock up, much to the delight of the “drifter” crowd.
Ah. Makes sense.
I haven’t had an RWD drive since 2004 or so, so you’re on the money there.
I have taught and worked on keyless drive systems.
On the cars I work on when the trans is not in park it either takes a 3second push or two pushes in quick secession to turn off the engine. After the first push there is a message in the instrument cluster telling you to push it again if you want to turn off the engine.
I have never seen a keyless drive system where the car would start unless the key was in the car. Hanging on a coat hook nearby just won’t do it. Again on my cars the message is “No key detected”
If someone gets out of the car with the key there are chimes and messages, but the engine continues to run. However once you turn it off, it won’t restart until you have a key inside the car. The technical term for this condition is “Reebok mode”
The safety investigation is over floor mats that get bunched up under the accelerator pedal and mechanically hold it wide open. There are no claims (by the government or anyone else without tin foil hats) that this is an engine ECU issue.
BTW I experienced this exact issue on a Mazada RX-8 where the bottom of the floor mat had these little plastic teeth that are supposed to grab the carpet to keep the mat from moving. The dipshit Mazada instructor had turned the mat over to keep the top of it clean. I went to move the car, I pulled out of the parking space, floored the gas for about 1 second and let off. The little plastic teeth grabbed the gas pedal and held it to the floor.
Then the turbo boost kicked in. :eek: I hit the brakes, but this being a training car the rotors were rusty. :eek::eek: Brakes did not grab right away. :eek::eek::eek: I am looking at the front of an F250 4X4 pickup as I am still accelerating. I have to admit that the thought did drift through my mind that if I hit the truck I would never get to retire as the paperwork for 3 different companies from the accident would keep me busy until I was old and gray.
Anyway I pushed the stick to neutral (auto trans) and reached for the key, right as the brakes wore off all the rust, and the car stopped.
I killed the key and found the mat trapping the gas pedal.
I wanted to kill that other instructor. dumb shit.
All modern engines that I am aware of have a rev limiter, shifting to neutral will not blow up the engine.
FWIW back in 98 we did a track test of 6 competing cars. Mercedes 230, Lexus ES300, Infinity I30, BMW 328, Volvo S70, V-6 Honda Accord. As a group the Japanese cars had inferior brakes to the European cars, and the Toyota had the worst brakes of the bunch. So the fact that he had trouble stopping the car does not surprise me.
Maybe not 100% activation (this was years ago) but it was enough that any yutz who’d bothered to look at it would be able to tell it was on with no hesitation. I think it was a Geo Metro.
Well, that’s the exact opposite from the response I’d expected, that’s for ever-loving sure.
The parking brake is a mechanical extension of whatever braking system the car has. It has more mechanical hp than the engine and will lock up the wheels unless it is a drum system that is out of adjustment.
There is a danger involved with using the parking brake and I’m posting this so people will understand it. If the brakes are not balanced then rapid deployment of the parking brake could lock one brake up over the other. This will put the car into a spin (been there, done that). This is a more prevalent probem with rear drum brakes which are notorious for not self adjusting equally. It can also occur with disc brakes if one caliper is sticking causing only one side of the brake pads to engage. If you are in a situation where you need to use the parking brake then do not slam the brake on but engage it in a controlled/even manner.
Now on to power brakes. These work by using the mechanical energy of a vacuum chamber. The chamber is drawn down through the vacuum created by the engine under normal load. If the engine is racing then no vacuum is available. Loss of power assist is NOT a loss of brakes. What occurs is a SUBSTANTIAL change in the amount of foot pressure needed to run the brakes. Instead of 5 lbs of pressure from your foot it may take 150 lbs of pressure. Most people are capable of generating this kind of pressure. It is important that a person understand that a loss of power assist does not mean a loss of brakes, it just means a much greater amount of pedal force is needed. Please note this is a different situation than a loss of braking due to a ruptured line or bad master cylinder which means you need to pump the brakes to recover whatever mechanical action is available.
I’ll join those noting that this “expert” is something of a nincompoop: neither steering nor brakes will be disabled. Both lose their power assist, and thus require more effort.
In the case of brakes the extra effort is substantial, as Magiver notes. In the case of steering, unless you are talking about maneuvers like parking, the extra effort is minor.
Yeah, a friend did that one day when we were headed down a curvy road to save gas while we were going about 40.
Boy, that was exciting.