The Unintended Acceleration Test

"They died in Toyotas, leaving many questions." The headline on the front page of Monday's edition ofUSA Today, topped by a Toyota logo, wrapped in black, and featuring photographs of six people killed in what were claimed unintended acceleration incidents, was nothing if not sensationalist.

USA Todayreporters examined 25 of the 43 fatal accidents that are among the 2600 complaints reported to NHTSA since 2000 regarding alleged unintended acceleration incidents in Toyota vehicles.USA Todayreported its investigation revealed the following facts:

• The 25 cases involved nine Toyota models and 20 model years, and a majority of the vehicles involved were not among the Toyota vehicles recalled
• Three drivers were allegedly intoxicated
• 12 of the 25 drivers were over 60 years of age; nine were over 70
• 11 of the fatal crashes were on highways; 10 on town or city streets; four were in parking lots
• Only two fatalities occurred with the car in reverse

USA Todaythen reported the known facts around each of the 25 crashes.

The story did indeed raise lots of questions. But it didn't address the most important ones, namely:

• Did the drivers involved attempt to stop their vehicles?
• If they did, were they pressing the brake pedal, or were they, in their panic, mistakenly flooring the gas pedal instead?
• In an unintended acceleration incident, can the engine really out-power the brakes?

There is little doubt pedal misapplication is a common cause of so-called unintended acceleration incidents. In the aftermath of the Audi "sudden acceleration" affair in the mid-80s,Motor Trendtesting director Kim Reynolds, then working atRoad & Trackmagazine, helped conduct a test that proved conclusively drivers could press the gas pedal and believe they had their foot on the brake. It took video evidence from cameras mounted in the car to convince them otherwise.

"Yes, it happens," said an instructor at an advanced driving school when asked about pedal misapplication, "especially in a panic situation." Had the instructor, who did not want to be named, ever been in a car when a student had pressed the gas instead of the brake? "Oh yeah," he replied. "I've even done it myself. The problem for most people is when it happens they panic, and when they panic they become target-fixated [on the object or vehicle they are about to collide with]. Then it's all over."

In the absence of "black box" data that can determine brake and throttle positions, relative to speed and time, it is impossible to determine exactly what caused the 25 fatal crashesUSA Todayreporters reviewed. Much of the evidence used to reconstruct the chain of events leading up to the crash is purely circumstantial. Even eyewitness reports are unreliable. As a veteran crash investigator observes: "The only way to know what truly caused a crash is to be driving the car when it happened."

So we can only speculate as to the answers to the first two questions. But we can certainly test the answer to the third.

During the regular performance testing for our seven-car family sedan comparison, we devised a simple additional test: We accelerated each of the cars to just under 60 mph, floored the gas, and then within two seconds nailed the brakes while keeping the gas pedal floored. We then measured the distance it took to bring each of the cars to a complete halt from 60 mph, and compared that to our tested 60-0 mph braking distances. Same cars, same track surface, same driver.

Our key finding: EVEN WITH THE GAS PEDAL FLOORED, ALL CARS DID STOP.

The Toyota Camry (which had been recalled and had its engine management system reflashed to include the brake override function) and the 2011 Sonata were the only two that automatically cut engine power while the brake was applied, and as a result stopping distances were virtually unchanged (as they were with the still revving Nissan). The Subaru Legacy took 3 feet longer to stop, while the Honda Accord took 4 feet. The worst performers -- Ford Fusion and Chevy Malibu -- stopped within 28 and 37 feet of their respective normal 60-0 mph braking distances.

Our conclusion? Even if a vehicle's electronic throttle system somehow triggered an unintentional acceleration incident, modern braking systems are good enough to over-power the engine and bring the vehicle safely to a halt within a reasonable distance.

As this chart shows, each car's braking system is capable of generating more than 500 braking horsepower, and no car in this group has an engine with more than 200 horsepower. A key point to remember, however: You must brake HARD. Merely squeezing the brakes on a runaway vehicle will gradually overheat them to the point where they'll fade to uselessness.

Two best ways to stop a runaway car

• Shift to Neutral and brake to a stop.

Switch off the engine (press and hold the Start/Stop button 3 seconds)

• and brake to a stop.