From Wikipedia (cites LA Times):
On August 28, 2009, a two-car collision killed four people riding in a Lexus dealer provided loaner ES 350 in San Diego, California.[14][15][16] The NHTSA released a safety investigation report on October 25, finding that the accident vehicle was wrongly fitted with all-weather rubber floor mats meant for the RX 400h SUV, and that these mats were not secured by either of the two retaining clips.[17] The brake hardware also showed signs of heavy braking consistent with a stuck accelerator pedal.[17] The report stated that the accelerator pedal's hinge did not allow relieving obstructions, the loss of vacuum power assist at full throttle increased stopping distances fivefold, and the dashboard lacked directions for the three-second emergency press of the push button keyless ignition. NHTSA investigators also recovered the accident vehicle's accelerator pedal, which was still "bonded" to the SUV floor mat.[17]
Another investigation conducted by the San Diego County Sheriff's Department found that three days prior to the crash another customer had complained to the dealership about the floor mat trapping the same loaner car's accelerator pedal while driving.[18] The prior driver had switched to neutral and tugged on the floor mat, which released the accelerator.[18]
