Prius and It’s Cruise Control

The Toyota Prius sometimes accelerates while in cruise control, rocketing past the set speed and sending drivers on wild rides, according to some owners and auto safety experts.

The computer guru blamed the problem not on floor mats or a sticky accelerator pedal, as Toyota has maintained, but on bad software. An exasperated Wozniak expressed frustration with his efforts to contact Toyota and the National Highway Traffic Safety Administration.

Clarence Ditlow, the executive director of the Center for Auto Safety, a Washington-based group focused on car safety, said his group has received about 10 cruise-control complaints from Prius owners -- roughly 5 percent of the overall complaints his organization has received about the hybrid.

The Prius is among the 8.5 million Toyota vehicles recalled in recent months for problems related to gas pedals and brakes. Just this week, Toyota recalled hundreds of thousands of 2010 Priuses for problems associated with its brake system.

CNN spoke with several owners of previous Prius models who say they were experiencing the same problem: When they resumed cruise control, the car took off as if it had a mind of its own and resisted when they slammed on the brakes. A spokeswoman for NHTSA refused comment for this story, saying the government agency is looking at the Prius braking system but not potential cruise-control problems.


Feds and Toyota too close?

Towns asked in a February 3 letter to Toyota CEO Yoshimi Inaba.

Grover Walton repeatedly slammed on the brakes of his 2008 Toyota Prius on a road trip to visit his granddaughters in South Carolina last October. The car lurched back and forth, and gained speed.

The incident began, he said, when he hit the "resume" button on his cruise control, thinking he'd speed back up to around 63 mph. The car got up to 75 mph.

The car wouldn't shift into neutral. The car came to a stop on the shoulder of the road. Many automakers have had cruise-control problems over the years, including Ford, which last October added 4.5 million older model vehicles to a recall over a faulty cruise control switch that could overheat.

It's not surprising to him to hear of Prius owners complaining about possible cruise-control problems. Hybrid vehicles are among the most complex. The cars have separate electric and gasoline engines and a regenerative braking system that uses energy from the car's wheels to help charge its battery.

Finding the root cause of the problem, Friedman said, gets tricky. "If you test them independently, they all work perfectly well."


Owners: It's not the floor mat

Barbara Walton never uses the cruise control any more, and she stays in the right lane just in case she needs to pull over quickly.

The dealership that fixed the car blamed the problem on floor mats. "Initially, we thought Toyota would be pretty receptive," her husband said. The problem has not resurfaced.

(Taken from CNN: By Christina Zdanowicz and Wayne Drash)