Accident investigators have weighed in on the fiery crash that killed Fast and Furious actor Paul Walker. And the conclusion is that unsafe driving—not an issue with the car—was what led to the accident.

The Porsche GT in which Walker was a passenger was going 93 miles per hour—double the posted 45-mph speed limit—when it crashed, according to an investigation revealed today (but not yet released in full) by the Los Angeles County Sheriff's Department.

The Los Angeles Times this afternoon quoted Sheriff Commander Mike Parker as saying: “Investigators determined the cause of the fatal solo-vehicle collision was unsafe speed for the roadway conditions.”

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Speed and driver judgment were primary factors. No mechanical fault was found with the Porsche, although the tires on the car were nine years old, and that was found to be a contributing factor. Even tires on low-mileage high-performance cars should be replaced at six years, manufacturers advise, and some sources cited a call in the Porsche's owners manual to change them at four years.

"There is also evidence that this particular vehicle had been altered from its original design state and had not been maintained properly," confirmed Porsche Cars North America, as part of a released statement. "However, there is no evidence of any mechanical malfunction. We stand by our Carrera GT and by the investigation and conclusions of the responsible authorities."

Earlier this year, the coroner reportsuggested speeds of 100 mph based on the injuries, but accident investigators used extensive data analysis to arrive at the 93-mph figure. Investigators documented skid marks indicating that the car had spun out on the pavement, then hit the sidewalk before smashing into a tree and light post.

The results run counter to some earlier media reports that suggested that the Porsche, piloted by Roger Rodas, at a charity event November 30, could have been traveling at lower speeds but had some kind of catastrophic failure.

Now with the case nearly closed, the cause looks more clear-cut: a tragic, deadly lapse in judgment.

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