Toyota is still recovering from its well-publicized problems with unintended acceleration in its vehicles, and a slew of independent consultants, including the government, is testing the vehicles in question in order to determine what caused the issue.

Leaked data from preliminary testing by the National Highway Traffic Safety Administration has shown that driver error, rather than electronics or design flaws, may have been a factor in at least some of the cases, according to USA Today. Electronic data recorders in the vehicle can tell analysts exactly what was happening at the time of the crash. A driver who meant to slam on the brakes may have accidentally hit the gas in the heat of the moment and blamed it on unintended acceleration.

It is unclear how many of the cases were caused by driver error. Toyota has pointed to possible problems with poorly-fitting floor mats and sticky gas pedals, and has disputed the findings of Professor Dan Gilbert, an independent consultant who found that the vehicle’s electronic system may be at fault.

Unintended acceleration in Toyota vehicles has accounted for an estimated 80 fatalities, according to the NHTSA, although that number may drop with the new findings.

Drivers interested in choosing a Toyota for their next vehicle may want to look at used Toyota vehicles, as older models of Corollas and Camrys are known to be unaffected by the problem.