See How Fox said:

"I pushed the gas pedal to pass a car and it did something kind of funny... it jumped and it just stuck there," the 61-year-old driver said at a news conference.

A patrol car pulled alongside the Prius and officers told Sikes over a loudspeaker to push the brake pedal to the floor and apply the emergency brake.

"They also got it going on a steep upgrade," said Officer Jesse Udovich. "Between those three things, they got it to slow down."

After the car decelerated to about 50 mph, Sikes turned off the engine and coasted to a halt.

The officer then maneuvered his car in front of the Prius as a precautionary block, Udovich said.

http://www.fox5sandiego.com/business/sns-ap-us-runaway-prius,0,2927468.story