They are moments which command great attention in the media when they happen — a vehicle inexplicably “runs away,” out of control, on its driver. Often these incidents spark social media frenzies with keyboard speculators offering every possible explanation as to what went wrong even before the actual investigation has finished.
The odds of you having a runaway event though are about akin to winning the lottery. They do happen, but in relation to the other safety threats a driver may face, the chances are extremely small.
We’ve all read or heard stories of runaway cars though — vehicles that suddenly accelerate or refuse to slow down no matter what the driver does. They are terrifying and over the years have led to recalls, lawsuits and debates about technology and human error. Understanding what causes cars to run away is the key to respond safely if it ever happens.
Runaway vehicle moments usually fall into three categories: mechanical failures. electronic glitches or driver error.
Before the era of computer controlled engines, cars used mechanical cables and linkages to control the throttle. These could stick, fray or jam, holding the throttle open. Floor mates were another surprisingly common culprit — a loose or ill fitting mat could pin the accelerator to the floor. This was the central issue in Toyota’s highly publicized 2009-2010 recalls.
Other mechanical issues include sticking accelerator pedals due to worn springs or bushings, and malfunctioning cruise control systems that fail to disengage. These problems are way less common in modern cars, but they do occasionally surface.
Today’s vehicles rely on electronic throttle control (ETC) — sensors at the pedal send signals to a computer, which commands an electric motor at the throttle body. This system improves fuel efficiency and integrates smoothly with cruise control, stability systems and hybrids. The main concern here is that it is software driven. Glitches or sensor mismatches occasionally happen.
In theory, if the pedal sensor and throttle body disagree, the system should shift or revert to “limp mode” which, according to the global data and analytics firm JD Power, is a safety feature that restricts a car’s engine power and speed when a serious problem with the engine or transmission is detected. There have been isolated reports of unintended acceleration possibly linked to software bugs. Most manufacturers now include a “brake override” where if you press the brake the computer cuts throttle power.
Investigations by Transport Canada show that the majority of modern unintended acceleration cases stem from human pedal misapplication. In stressful moments, drivers sometimes hit the accelerator instead of the brake. Thinking that the brake suddenly doesn’t work now, they press harder on the accelerator causing the car to run away. While less sensational than blaming software, human error is both common and deadly.
If your car suddenly accelerates uncontrollably, what you do in those next 10 seconds could save your life.
Stay calm, keep your eyes on the road and brake firmly. Modern brakes are strong enough to overpower the engine. Apply hard, steady pressure - don’t pump.
Shift to neutral. This disconnects the engine from the wheels. The motor may be screaming - but you’ll stop accelerating.
Shut down the engine. If your vehicle has a key, turn it one click back - but not all the way to “lock”. That will lock your steering wheel at a time when steering is vital. If you have a push button ignition - press and hold. A one touch press like you use to start up won’t work - that’s a safety feature. Press and hold for at least 3 to 5 seconds.
Use the parking brake if necessary. Apply gradually as a hard yank could cause a skid. But what about those electronic parking brakes which can be small buttons or switches?
In an emergency if you press or lift and hold the electronic parking brake while moving the system interprets that as an emergency request. The car’s computer commands the system to apply braking force in a controlled way and not just lock up the wheels. Each vehicle model is different though. It’s crucial to read the owner’s manual and understand how your electronic park brake system works.
Prevention as always is best. Use properly fitted floor mats, secured in place. Replace worn or sticky parts. Update software promptly. Read the owner’s manual. Rehearse and practice. How many clicks to enter “neutral” from “drive”? Can you find the parking brake and other switches while keeping eyes on the road?
A runaway car is terrifying. But calm hands, firm brakes and quick thinking keeps you, not the car, in charge.
