The National Highway Traffic Safety Administration, a division of the U.S. Department of Transportation, has concluded that instances of sudden unintended acceleration (SUA) reported in four Tesla models stemmed from mistakes made by drivers.

The NHTSA initiated its investigation into these allegations last January, prompted by a request from Brian Sparks for a recall of all Model S, Model X, and Model 3 vehicles manufactured in 2013 or later. During the assessment, the NHTSA examined the 232 SUA reports submitted by Sparks, alongside an additional 14 complaints and comprehensive crash data.

The Office of Defects Investigation at the NHTSA has now established that the crashes involving SUA referenced by Sparks were the result of driver actions. Consequently, the NHTSA is rejecting Sparks’ request for a formal review of 662,109 vehicles and a potential recall.

“The investigation revealed no defects within the accelerator pedal assemblies, motor control systems, or braking mechanisms that played a role in any of the reported events,” the report details. “No design flaw was identified that would increase the probability of incorrect pedal use. The proposed explanation of a possible electronic source for SUA in these vehicles relies on incorrect understandings of the system’s architecture and recorded data.”

Tesla had earlier refuted the allegations, labeling the petition as “entirely untrue” and revealing that Sparks held a short position in Tesla stock.

“We thoroughly examine every situation where a driver reports that their vehicle accelerated without their intention, and in every instance where we had access to the vehicle’s data, we verified that the car functioned as intended,” the company stated last January. “Specifically, the car accelerates only when the driver instructs it to, and decelerates or stops when the driver uses the brakes.”

The NHTSA’s investigation corroborated Tesla’s own conclusions. TechCrunch has contacted Tesla for comment and will provide updates as they become available.