Tesla Autopilot Collides with the 4th Amendment

Guest Blog by Jesse Halfon

Last month, two California Highway Patrol (CHP) officers made news following an arrest for drunk driving. What made the arrest unusual was that the officers initially observed the driver asleep behind the wheel while the car, a Tesla Model S, drove 70 mph on Autopilot, the vehicle’s semi-automated driving system.

Much of the media coverage about the incident revolved around the CHP maneuver to safely bring the vehicle to a stop. The officers were able to manipulate Tesla Autopilot to slow down and ultimately stop mid-highway using two patrol vehicles, one in front and one behind the ‘driverless’ car.

But USC Law Professor Orin Kerr mused online about a constitutional quandary relating to the stop, asking, “At what point is a driver asleep in an electric car that is on autopilot “seized” by the police slowing down and stopping the car by getting in front of it?” This question centered around when a person asleep was seized,a reasonable 4th Amendment inquiry given the U.S. Supreme Court standard that a seizure occurs when a reasonable person would not have felt ‘free to leave’ or otherwise terminate the encounter with law enforcement.[1] 

Kerr’s issue was largely hypothetical given that the police in this situation unquestionably had the legal right to stop the vehicle (and thereby seize the driver) based on public safety concerns alone.

However, a larger 4th Amendment question regarding semi-automated vehicles looms. Namely, what constitutes’reasonable suspicion’ to stop the driver of a vehicle on Autopilot for a traditional traffic violation like ‘reckless driving’ or ‘careless driving’?[2] Though there are no current laws that prescribe the safe operation of a semi-autonomous vehicle, many common traffic offenses are implicated by the use of automated driving features.

Some ‘automated’ traffic violations will be unchanged from the perspective of law enforcement. For example, if a vehicle on Autopilot[3] fails to properly stay inits lane, the officer can assess the vehicle’s behavior objectively and ticket the driver who is ultimately responsible for safe operation of the automobile.Other specific traffic violations will also be clear-cut. New York, for example still requires by statute that a driver keep at least one hand on the wheel.[4] Many states ban texting while driving, which though often ambiguous, allows for more obvious visual cues for an officer to assess.

However, other traffic violations like reckless driving[5] will be more difficult to assess in the context of semi-automated driving.

YouTube is filled with videos of people playing cards, dancing, and doing various other non-driving activities in their Teslas while Autopilot is activated. While most of these videos are performative, real-world scenarios are commonplace. Indeed, for many consumers, the entire point of having a semi-autonomous driving system is to enable safe multi-tasking while behind the wheel.

Take for example, the Tesla driver who is seen biting into a cheeseburger with both hands on the sandwich (and no hands on the wheel). Is this sufficient for an officer to stop a driver for careless driving?Or what about a driver writing a note on a piece of paper in the center console while talking on the phone. If during this activity, the driver’s eyes are off the road for 3-4 seconds, is there reasonable suspicion of ‘reckless driving’that would justify a stop? 5-6 seconds? 10? 20?

In these types of cases, the driver may argue that they were safely monitoring their semi-automated vehicle within the appropriate technological parameters. If a vehicle is maintaining a safe speed and lane-keeping on a low traffic highway, drivers will protest – how can they be judged as ‘careless’ or ‘reckless’ for light multi-tasking or brief recreation while the car drives itself?

The 4th Amendment calculus will be especially complicated for officers given that they will be unable to determine from their vantage point whether a semi-autonomous system is even activated. Autopilot is an optional upgrade for Tesla vehicles and vehicles that are equipped with L2/L3 systems will often be driven inattentively without the ‘driverless’ feature enabled. Moreover, most vehicles driven today don’t even have advanced automated driving features.

A Tesla driver whose hands are off the steering wheel could be safely multi-tasking using Autopilot. But they could also be steering with their legs or not at all. This leaves the officer, tasked with monitoring safe driving for public protection, in a difficult situation. It also leaves drivers, who take advantage of semi-automated systems, vulnerable to traffic stops that are arguably unnecessary and burdensome.

Of course, a driver may succeed in convincing a patrol office not to issue a ticket by explaining their carefully considered use of the semi-automated vehicle. Or the driver could have a ‘careless driving’ ticket dismissed in court using the rational of safely using the technology. But once a police-citizen interaction is initiated, the stakes are high.

Designing a semi-automated vehicle that defines the parameters of safe driving is complex. Crafting constitutional jurisprudence that defines the parameters police behavior may be even more complex. Hopefully the Courts are up to the task of navigating this challenging legal terrain.

Jesse Halfon is an attorney in Dykema’s Automotive and Products Liability practice group and a member of its Mobility and Advanced Transportation Team.


[1] United States v. Mendenhall, 446 U.S. 544, 554 (1980); United States v. Drayton, 536 U.S. 194, 202 (2002);Florida v. Bostick, 501 U.S. 429, 435-36 (1991).

[2] Some traffic violations are misdemeanors or felonies. To make an arrest in public for a misdemeanor, an officer needs probable cause and the crime must have occurred in the officer’s presence.  For a Terry stop involving a traffic misdemeanor, only reasonable suspicion is required.

[3] Tesla Autopilot is one of several semi-automated systems currently on the market. Others,including Cadillac Super Cruise Mercedes-Benz Drive Pilot and Volvo’s Pilot Assist offer comparable capabilities.

[4] New York Vehicle and Traffic Law § 1226.

[5] Most states have a criminal offense for reckless driving. Michigan’s statute is representative and defines reckless driving as the operation of a vehicle “in willful or wanton disregard for the safety of persons or property”.  See Michigan Motor Vehicle Code § 257.626. Michigan also has a civil infraction for careless driving that is violated when a vehicle is operated in a ‘careless or negligent manner’. See Michigan Motor Vehicle Code § 257.626b