The accident that killed the 40-year-old "Fast & Furious" actor and his friend, 38--year-old Roger Rodas, also had nothing to do with debris in the roadway, according to a law enforcement official with knowledge of the investigation, who spoke with the Associated Press.
The official said investigators are looking at "speed and speed alone."
Rodas, Walker's friend and financial adviser, was driving the 2005 Porsche Carrera GT when it crashed into a light pole and tree and burst into flames in Valencia on Nov. 30.
The data recorders of the car survived and may produce information to pinpoint the speed, according to detectives.
Investigators have a speed range at which they think the car was traveling but they are waiting for Porsche engineers to extract information from onboard data collectors.
The Associated Press contributed to this report.