Monday, February 22, 2010

HELP! My car won't stop!

As a crash reconstructionist with a Ph.D. in engineering, I've been asked by several people how to handle a runaway car. To my friends who drive Toyota and Lexus automobiles, and are concerned about sticking throttles:

At some point in your life, you’ll probably experience some type of accelerator malfunction. Here’s how to stay alive.

1. STAY CALM. It’s a sticking throttle, not a bomb. It’s unnerving for your car to accelerate on its own. The ‘pucker factor’ goes off the scale quickly, and I’m speaking from experience, because it’s happened to me twice. But you’re the driver, you’re an adult, and you are the only person who can fix the problem.

2. MOVE THE SHIFTER INTO NEUTRAL. Yes, it will shift into Neutral. Put your hand on the shifter. Move it one notch forward to Neutral. The engine speed (RPM) will increase to redline, but it has a limiter which will keep it from over-revving. It’ll get loud, but it doesn’t matter. It won’t explode. For cars with J-gate shifters, like the Lexus, you’ll need to move the lever to the side and then up. Don’t worry if you go too far and bang into reverse. At higher speeds, you’ll get a loud racket, but the cogs won’t engage. Don’t freak out - just move it back into Neutral.

3. PRESS THE BRAKE PEDAL FIRMLY. Don't pump the brakes- you'll overheat them, and then they won't work. If the car doesn't slow down, reach down and tug the floor mat away from the pedals. After reading Rhonda Smith's testimony, I believe this is another danger area. Make certain the space behind the brake pedal is clear.

4. MOVE TO THE SHOULDER. The car is going to start slowing down when you shift into Neutral. Your steering and brakes still work, and they have plenty of power, because the engine is still going nuts. Use the time to make it to the shoulder. Don’t veer suddenly, don’t swerve. The engine is revving madly, but you aren’t. Check traffic and use your signal.

5. SHUT THE CAR OFF. Yes, while it’s in Neutral. It’s not illegal. It won't hurt the car. With a key ignition, you won’t be able to rotate the key all the way around to remove it. Just turn it one click to the ‘accessory’ position. This will kill the engine.

6. For cars with starter buttons, you need to PRESS AND HOLD the starter button to shut off the engine. Hold it about 4 seconds in Toyota vehicles, and about 2 seconds in Nissans. In Nissans, if you hit the starter button three times in rapid succession, the computer gets the message and will kill the engine that way, too. Toyota computers just ignore this panic method. So, drill this into your mind: PRESS AND HOLD.

Remember the tragic crash in California that killed a CHP Trooper and his family? I’ve spoken with a reconstructionist familiar with the crash, and he indicated that the trooper didn’t know he had to push and hold the starter button to shut the car off. Most people don’t, and to be fair, most people aren’t going to think about this as their vehicle is accelerating like it’s possessed by an evil spirit. Remember: PRESS AND HOLD.

Pressing and holding the button will also turn the engine off while the car is still accelerating, too. And if this is what you choose to do, that’s fine. Just be aware that you lose power assist for the brakes and for the steering wheel. Be prepared for the brake pedal to become hard to press, and for the steering wheel to become hard to turn. They’ll still work, but you’ll have to use some muscle.

Also, your brakes will overpower your car’s engine. Yes, even with the engine screaming at 6000 RPM (and note, it’s RPM. Not RPM’s, or RPMs. The ‘s’ is already baked-in. Hearing or reading the term ‘RPMs’ is like stroking a cat backwards).

The caveat with using your brakes to overpower your engine is that you have to stomp them. Pound them through the floor. And you must keep them pressed until the car comes to a stop.

Do not ‘pulse’ the brake pedal. This is bad, because it overheats the brakes, and the car gains speed as soon as you release the brakes. If you overheat your brakes, they won’t stop your car. But they will absolutely overpower the engine long enough to get the car stopped. Just don’t let up until the car is stopped, even if they’re smoking. That kind of smoking isn't hazardous to your health. They’ll be okay, and they’re cheap and easy to replace. Once you’re stopped, shift into neutral (if you haven't already done so) and kill the engine. On keyed ignition vehicles, DO NOT shift into park and/or remove the key while the vehicle is still in motion. Doing so will cause the steering wheel to lock. This is generally a bad thing to induce in a moving vehicle.

As mentioned previously, I’ve had unintended acceleration happen twice. The first time was a binding accelerator linkage in a 1992 Corvette. It had been serviced by a speed shop, and they'd left the oil cap under the throttle lever. Out on the road, I opened her up. Then the cap got under the lever, and I had to change my pants. After, of course, I pushed the clutch in and got the thing stopped in neutral.

The second time was a floormat issue. The floormat issue, ironically, occurred a few years ago in a Lexus that I’d just purchased. It has an electronic throttle control similar to the ones on the recalled vehicles, although mine was not involved in the recall. The cruise was set at 70 mph, light traffic on a major highway. I shifted my feet, and the car took off.

Admittedly, the first reaction was to hit the brakes. This also shuts off the cruise control. The engine was still racing. And the traffic in front of me was coming up fast.

I hooked the toe of my shoe behind the accelerator and pulled. The car slowed down. I figured out what was going on, reached down, and pulled the mat away from the pedal.

The previous owner had installed an aftermarket set of rubber mats on top of the factory floormats. At the next exit, I dumped them in the trash.

Listen, people, floormats are replaceable. They’re available from your dealer for less than $100 in most cases. Buy a second set to use when you have company over, for God’s sake. But don’t shove a thick rubber mat up near the pedals and then wonder why it’s harder to operate the brakes and throttle. If you do need some kind of rubber trough to catch salt and snow and mud, then remove the factory mats and trim the replacements as necessary to ensure there’s no interference with the pedals.

In the case of the Toyota fiasco, I’m not convinced that Toyota even understands what’s going wrong. Shimming the accelerator pedal is a dubious fix, and sounds more like a convenient bystander that’s been charged with the crime because the real culprit can’t be found. The truth appears to be that Toyota couldn’t find the problem, so they hired Exponent, a very expensive and large forensic engineering firm, to try to find the problem. They batted zero, too.

The complexity in contemporary vehicle electronics is staggering. Repair manuals used to be a couple hundred pages of mechanical and electrical diagrams. Now there’s a dedicated manual on electrical troubleshooting that accompanies the mechanical manuals. And it’s usually a lot thicker than the mechanical book, too. Someone will probably eventually figure out that under some arcane operating condition, at just the right temperature and throttle position, the electronic throttle control gets a wide-open throttle signal. But until that happens, the best remedy for Toyota is to install software that kills the engine when the brake pedal is depressed. Nissan, BMW, Chrysler, and Volkswagen, among others, already have this incorporated into their own engine control architecture. Toyota made the decision not to use it. Which, as we see now, was a bone-headed decision that ended up killing people. Not the first time this has happened. Won't be the last.

In my line of work as a forensic reconstructionist, I’m frequently contacted by attorneys and insurance companies with requests to investigate alleged vehicle defects. Some prove valid, while many others do not.

In 2003, I testified in a court case against a major foreign manufacturer who used carbon steel screws to hold a reed valve in an exhaust gas recirculation assembly. The carbon steel screw heads would corrode, the reed valve would fall off, and 800+ F exhaust gas flowed into the air filter on top of the engine. This filter was a paper element soaked in oil that would reach ignition at 392 F. Engine fire? Absolutely. It happened to thousands of affected vehicles. More insidiously, though, was that the underhood fire generated dangerous gases such as carbon monoxide that were pulled in through the vehicle’s ventilation system at the base of the windshield. In several cases, the occupants would succumb to the gases, pass out, and then the car would run off the road and crash. The company’s strategy was to blame the engine fires on the crash instead. In most cases the crashes occurred at low speeds, because the engine would stall and the car would begin to slow down well before it left the roadway.

The evidence against the company was overwhelming. The jury agreed, and ended up awarding the plaintiff more than the original lawsuit had asked for.

The fix was simple: they should have used stainless steel screws instead of carbon steel. But for the savings of less than one cent per vehicle, they ended up killing several people and seriously injuring hundreds more.

Toyota, thankfully, doesn’t seem to be going down the same road. They’re owning up to the problem, but as I mentioned, it appears they don’t know exactly what that problem is. Rather than chase down a needle in electronic haystack, they should engineer a throttle-override that can be retrofitted to the recalled vehicles. And it could be done using software, keeping costs low. They’re already doing this with current production.

My car is still that same fancy Toyota that had the floormat problem. After two years and fifty thousand miles, it’s been the best car I’ve ever owned. And the crashworthiness of Toyota vehicles is still superior to many other manufacturers. If you want to give your Toyota away, I’ll take it. Gladly.

Cars are mechanical devices. And they’re designed by fallible humans. Mechanical devices will eventually break, and despite the best intentions, humans often fail, too. But try to make sure that you don't. If you get in a situation where the car suddenly accelerates on its own, keep your head, shift into neutral, and make it safely to the shoulder. Then change your pants.