The investigations by NHTSA and Toyota noted that the Prius's brakes had been applied and released at least 250 times since the last time the car was started. Toyota points out that the Prius is equipped with a form of brake override that reduces engine power when the brakes are applied hard, no matter what is happening with the gas pedal. Officer Niebert's report sheds some light on brake usage, as well. As soon as he caught up with the Prius, Niebert writes:

"The red brake lights were on for a period of time and would turn off, indicating the driver was possibly pumping the brakes. I was withing a mile of the vehicle and could smell the heated brakes, which indicated they had been used extensively.... The Prius moved into the #1 lane to go around another slower moving vehicle as it continued at over 90 mph. I positioned my patrol vehicle alongside the right side of the Prius after passing the slower moving vehicle. We were then just east of the Kitchen Creek Road undercrossing. I advised the driver over my public address (PA) system to lower the window and I confirmed that he could hear me. The right rear window of the Prius was half way down and I could clearly see the driver. I instructed him to try putting the car into neutral and turn the engine off. He shook his head side to side (indicating to me it did not work or he could not do it). I assumed that he [had] attempted to shut the vehicle off and continued to evaluate the situation.... The Prius and I were within 20 miles of the Mountain Springs Grade that leads to the Imperial County Desert. It is a steep 6 percent downgrade, which has a sharp left hand turn at the top and an advisory speed of 50 mph. If the Prius made it to that location, the ultimate result would have most likely led to a catastrophic ending."

Another thing that has not been clear is how applying the emergency brake at the same time as the main braking system had such a dramatic effect on the hybrid's speed and how a Prius could go 95 miles per hour in the first place. The answer to both questions, according to the report, is that the incident occurred on a hilly section of Interstate 8. Just after officer Niebert instructed Sikes to use the emergency brake, the cars headed up a steep grade.

"While we were still east of Kitchen Creek Road, I was alongside the right side of the Prius. I could see the driver sat up off his seat, indicating that he was possibly applying the brake pedal with his body weight. I was able to view his actions through the lowered right rear window. His back was arched, and both hands were pulling on the steering wheel. I noticed that the Prius slowed slightly, down to approximately 85 to 90 mph. The Prius gradually accelerated to 95 mph. The driver looked over at me briefly and appeared to be in a panicked state. I continued to assess his vehicle as our speed varied from 90 to 95 mph. As we approached two big rigs in the #2 lane, I moved in behind the Prius. After we passed the big rigs, the roadway straightened out and there were no other vehicles within sight ahead of us. The roadway ascends at this location, and it is a long uphill grade toward Crestwood Summit (approximately 4 miles). The Prius was mostly in the #2 lane, but slightly straddling the #1 lane. The brake lights were on and the Prius' speed was approximately 85 mph. I moved up alongside the left side of the Prius and instructed the driver with the PA system to apply both the brake pedal and the emergency brake simultaneously, while doing so I was going to pull up in front of the Prius and use my patrol vehicle to assist in stopping the Prius....

"I moved up directly in front of the Prius and matched its speed. I was preparing for the Prius to drive up against my rear bumper and make contact. As I looked in my rearview mirror, I noticed the Prius speed had dropped dramatically. The speedometer on the patrol vehicle indicated we had slowed to approximately 50 mph. Shortly thereafter, the Prius came to a stop by itself in the #1 lane after veering left the #2 lane. I stopped as well and backed up to make contact with the front bumper. I placed my patrol vehicle's rear bumper against the Prius' front bumper to prevent further movement. Neither the patrol vehicle nor the Toyota Prius sustained any external body damage."

Recent news reports have suggested this runaway Prius story is a publicity stunt. But if Sikes was looking for attention, according to Niebert's report, he was shy about it:

"Sikes refused to exit the ambulance once he observed to media video cameras on scene. He did not want to talk to the media and requested to leave once they were done filming....

"...a large number of media representatives were going to meet at the CHP El Cajon Area office at approximately 1530 hours to cover the story. The media originally wanted to drive to the scene where the Prius had come to a stop. Officer Pennings made this arrangement to avoid having multiple news vehicles on the freeway, which could have been a safety concern for both the media and motoring public.... Sikes was very reluctant to speak with the media. He preferred to go to Jacumba to meet with his wife, which was his original destination. He was ready to go home. I convinced him to go to the office in order to put the media at ease. I advised him the media would most likely seek him out if he did not speak to them voluntarily."

While Sikes's Prius was included in Toyota's recall of 3.4 million vehicles to reduce the likelihood of floor mat entrapment, the recall work had not been done. (Sikes told the CHP that he had taken the car in, but had been told his car wasn't part of a recall.)

"Sikes further stated he had taken his Prius to a dealership a few weeks prior for a recall notice. The dealership advised him that his vehicle was not part of a recall and sent him on his way...."

According to the CHP report, Niebert inspected Sikes's Prius after the incident and found there were floor mats in the vehicle, but says they were not interfering with the accelerator pedal afterward. He also found similar evidence as the Toyota/NHTSA investigation that the Prius's front brakes were worn out and there was a large amount of brake dust in the wheels. (Photo evidence by the CHP.)

"There was a large amount of brake dust and brake pad material in and around the wheels and on the ground near the front wheels. The brake pads located on the outer section of the brake caliper were worn down to what appeared to be nearly metal-to-metal. I visually inspected the brake pads and rotor through the open section of the front wheels. I did not remove or manipulate any parts of the vehicle. The accelerator pedal and brake pedal appeared to be in the normal resting position and were not in contact with the floor. The floor mat was in its normal placement and did not appear to be interfering with the pedals."

Perhaps most compelling is the testimony by Officer Todd Niebert that the driver, Sikes was in a state of shock following the incident. Niebert should be in a position to recognize genuine distress:

"I opened the driver's door of the Prius. The driver (identified as James Sikes) was visibly shaking and breathing deeply. He appeared to be in shock and stayed seated in the driver's seat. I asked him if he was okay and he stated that he thought so.... American Medical Response (AMR) 86 arrived on the scene and evaluated Sikes inside the ambulance. Sikes's blood pressure and pulse rate were very high..."

Later, Niebert states that when he approached Sikes:

"Sikes appeared to be extremely stressed from the incident and displayed signs of shock. He was clearly shaking and that slowly dissipated after some time. Sikes' eyes were opened wide and had the look of somebody who was really scared from the situation. His voice was labored and shaky, as well."

Sikes's take on events from the scene was also recorded in the report:

"Sikes stated that he was eastbound on I-8, west of Dunbar Lane traveling at approximately 70 in the #2 lane. He accelerated to maneuver around a slower moving vehicle and explained that the Prius just took off and continued to accelerate. 'It felt funny.' (Referring to the way the pedal felt when he pushed down on it.) He thought the pedal stayed down on the floor, but he was not sure. He tried to pull up on the accelerator with his hand three times with no effect. When he called 9-1-1, he was able to give his locations, but set the phone down on the passenger seat, so he could concentrate on driving."

—Eric Evarts

Be sure to follow Consumer Reports Cars blog (RSS) and Twitter (@CRcars) to keep up with the latest information and advice, also see our unintended acceleration guide.

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