When Otto first began testing its technology in California last year, a co-founder of the company sought to assure regulators it was developing driver-assistance systems on the state’s public roads and not self-driving semi trucks. The distinction is critical. Otto, which hopes to develop fully self-driving trucks, would not be required to obtain an autonomous-testing permit from the state if it was only testing driver-assistance features. But it would be against regulations for the San Francisco–based company to test self-driving systems on public roads without a permit, something that Otto could never obtain for its semi trucks because the state forbids the testing of autonomous vehicles with a gross weight of more than 10,001 pounds. New documents shed light on how Otto, a subsidiary of Uber, has attempted to demarcate that fine line in its conversations with state regulators. In May 2016, Otto co-founder Anthony Levandowski sent an email to California Department of Motor Vehicles officials that read: “The tech we are utilizing in California requires a driver in the driver’s seat with his foot actively and physically pressing the accelerator pedal in order for the truck to operate. So long as the active physical control of the human driver is confirmed by the pedal mechanism, the technology we’re building prevents the truck from getting into collisions by slowing down . . . and providing steering corrections. Therefore, we see this technology as a collision-avoidance system.” Levandowski asked the DMV to confirm that this definition would not run afoul of the state’s regulations. It’s not clear from emails, obtained via a public records request, how state regulators responded to the query. But Otto’s testing continued.

However, Otto’s communications with Colorado officials last fall prior to a self-driving demonstration with a cargo of Budweiser beer may have told a different story. In a document detailing testing procedures, Otto software engineer Scott Ryvola noted that Otto trucks drove the highways surrounding San Francisco on a daily basis. He described company testing not of driver-assist features, but rather of a “self-driving system” that operates in “self-driving mode.” He made no mention of any requirement to keep a foot on the accelerator. Ryvola also wrote that if the system experienced an anomaly or if the test driver decided to intervene, the person could disengage the self-driving system “by grabbing the steering wheel, applying the brake, applying throttle, flipping an engage button on the dash, or hitting a large red button next to the steering wheel.” This could indicate that drivers do not routinely have a foot on the accelerator pedal, but it is not clear.

“That discrepancy demands explanation,” says Bryant Walker Smith, a professor at the University of South Carolina and expert on autonomous-vehicle laws. “Trust is such an essential part of the development and deployment of these technologies, and no automated-driving developer should be playing games with regulators.” Since a Car and Driver report showcased Ryvola’s document last week, the DMV says it is further examining Otto’s operations in the state. Consumer Watchdog, a nonprofit organization that closely tracks autonomous testing in the state, has filed a formal complaint with the DMV and asked it to revoke the company’s vehicle registrations and stop Otto’s “robot truck” testing, which it called “illegal.” If the agency decides the trucks do contravene regulations on autonomous vehicles, Otto could face a choice between disabling its technology and performing its testing in another state. Uber, Otto’s parent company, opted to do the latter when its self-driving taxis faced a similar situation last December.

This is not the first time Otto, which was bought by Uber last August for $680 million, has attracted the attention of California officials. Otto was co-founded in January 2016 by Levandowski, previously a key engineer in Google’s self-driving-car project. He started by modifying a single semi truck in the driveway of his home in Palo Alto. Levandowski’s neighbors soon became unhappy about sharing space with a high-tech trucking startup. Palo Alto city government started receiving complaints in February 2016 about a truck parked on residential streets for weeks at time and employees coming and going throughout the day. By April, the reports indicated two trucks were parked there, leaving no room for fellow residents even to put their trash out. Palo Alto issued Levandowski a notice of violations, and he relocated the company to San Francisco in early May. During the city’s probe of the complaints, its code-enforcement investigators alerted the DMV to the possibly autonomous nature of the trucks. The agency quickly sent out its own sleuths. “Since you do not have a permit to test autonomous vehicles—especially since we have not promulgated regulations for the testing of commercial vehicles—we asked our investigators to contact you,” wrote Brian Soublet, deputy director of the DMV, to Levandowski in late April. Earlier this week, Levandowski reiterated his position that the systems tested in California are strictly driver-assist features.