Unintended Acceleration

Unintended acceleration is a term that refers to a vehicle moving further or faster than the driver intends. Typically, drivers report that the vehicle accelerates or maintains speed of its own accord and cannot be controlled. In some cases this has reportedly resulted in a crash, though fortunately most seem to occur at relatively low speed. A recent alleged case of unintended acceleration in the United States resulted in the deaths of four people in a high speed crash.

Claims of unintended acceleration are not that uncommon. In the early 1980’s a model in the range of a well known and respected European brand was identified by owners as being prone to this issue.  In the late 1980’s a popular Australian built passenger car was investigated after an unusually high number of incidents were reported. And more recently, a Japanese vehicle manufacturer was forced to recall vehicles in what could become one of the largest vehicle recalls in history.

In the first two cases mentioned, no mechanical fault could be found with the vehicles and the cause was deemed to relate to the positioning of the brake and accelerator pedals, which allowed the driver to mistakenly depress the accelerator instead of the brake. Significantly, for one of these vehicles, reported incidents almost completely stopped in later models when some minor changes were made to the pedal area. In the other, the manufacturer introduced a system that closed the throttle if the brake and accelerator were depressed at the same time. This was apparently also effective.

In the latest case, the issue has been blamed on a manufacturing defect, though some industry commentators remain sceptical that this is the entire cause, with some suggesting that electrical issues with the vehicle’s drive-by-wire throttle could be to blame. 

Jammed throttle linkages, accelerator pedals trapped by floor mats and cruise control systems that refuse to disengage could also be regarded as unintended acceleration events.

Both local and overseas media have presented some confusing and often inaccurate explanations of the problem, as well as some questionable advice to motorists who experience an unintended acceleration event.  

What to do if faced with an unintended acceleration event

The following information is provided as a guide. Every unintended acceleration event will be different, as will the road and traffic conditions at the time. You will therefore need to make your own judgement as to the safest course of action to take for your particular situation. Above all, stay calm and consider the consequences of your actions.

• Identify a safe place to stop and aim for it. Consider what effect your actions will have on other road users.
• Switch off the ignition. Take care not to lock the steering while the vehicle is moving.  If your car has a push button stop, remember that you may have to hold the button down for several seconds before the vehicle responds.
• Move the gearshift to Neutral. Do not select Park while the vehicle is moving. If the engine hasn’t stopped, it may over speed, resulting in internal damage.
• Cancel or switch off cruise control if in use.
• Apply the brake. Use both feet on the pedal if necessary. 
• Do not pump the brake pedal. This may reduce the number of assisted brake applications available.
• Use the hand brake judiciously. Avoid locking rear wheels as that could send the vehicle out of control.
• Is the accelerator pedal is jammed down? If so, can you free it without compromising control of the vehicle? 
• Think about the situation and what you’re doing. If the brake pedal feels like it goes to the floor, doesn’t have a ‘solid’ feel or the vehicle feels like it speeds up when the brake is depressed, you need to ask yourself if you really have your foot on the brake.
• If all else fails, consider your options. For example, sideswiping a guard rail or other structure will cause extensive damage but may assist in reducing speed, and is vastly preferable to hitting a pedestrian, an oncoming vehicle or other ‘hard’ object.
• Have the vehicle checked to identify and correct any mechanical or electrical issue that caused the problem.