Case of the Month: The brakes don’t work!

Oct 2, 2018 by

In freeway traffic, the insured was approaching a vehicle that was slowing in front of her, she reportedly applied the brakes but the vehicle would not stop! You can guess what happened next. Yes, a call to her insurance company.

 

Rollover damage from the accident.

GARRETT ENGINEERS, INC. was assigned to inspect and photograph the insured’s 2015 Jeep Grand Cherokee, and complete the following:
• Determine if a manufacturing defect, pre-incident mechanical failure, service error, or wear-and-tear issue in the brake or throttle systems caused or contributed to the date-of-loss incident.
• Identify an open manufacturing recall issue which could have caused or contributed to the date-of-loss incident.
• Download the Event Data Recorder (EDR) with the Crash Data Retrieval (CDR) tool to determine if a fault within the brake and/or throttle system could have caused the date-of-loss incident.

An inspection was performed of the front and rear brake systems including the pads, rotors, calipers, ABS sensors and cables and all other components. The brakes were found in good, safe operating condition. No visible brake fluid leaks were detected in the brake fluid lines or components. No skid mark indicators were located on the front tire treads indicating that the vehicle’s ABS was operating properly prior to and during the date-of-loss impact.

Next, the electronic throttle pedal and its mechanism was inspected and found to be in good, safe condition and operated properly. No problems here.

Sometimes, having extra floor mats can have an effect on catching the throttle pedal but its positioning showed that the extra mat did not interfere in this case.

Only one open recall was found for the vehicle from the National Highway Traffic Safety Administration but it was for a cruise control problem not related to this incident. So what did malfunction?

So next in the investigation came the Event Data Recorder (EDR) download and the truth came to light. The EDR shows the vehicle performance information up to 5 seconds before the impact occurs. Information like engine rpm, throttle percentage, vehicle speed, brake activation, and ABS activation, this information can be very telling during the investigation.

The CDR download of the EDR module recorded that the brake system was not activated during the 5 seconds prior to airbag deployment. The throttle pedal was fully engaged for the first 3 of the recorded 5 seconds. The pedal was then quickly released and sharply re-engaged to fully (100%) open at approximately 1 second prior to the airbag deployment. This recorded data indicated a possible pedal identification error during, at least, the last five-seconds prior to the rollover.

Extra aftermarket floor mat.

The insured thought she was stepping on the brake pedal but in reality she was stepping on the accelerator pedal! A very high percentage of unwanted acceleration cases are pedal misidentification, not a malfunction of the throttle system or the brake system.

When the Event Data Recorder collects this pre-impact data, it can show us What Really Happened. So the mechanical systems of the vehicle were operating properly, it was just a simple driver error.

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