A video posted to YouTube last year provides proof that some people can’t be trusted behind the wheel even when their car is doing all the driving. In the clip, the driver tests the automatic cruise control and lane assist in an Infiniti Q50 by hopping into the passenger seat as the car hurtles down the autobahn in Germany. Who would be liable in an accident – the carmaker or the driver?

Several carmakers are preparing to introduce technology that will let vehicles take even greater control of steering, braking, and accelerating on stretches of highway. But these vehicles are increasingly being designed to keep an eye on the driver after he or she has handed over control. It will be important to make sure the driver isn’t too distracted to regain control if necessary (you can forget taking a nap or reading a book), and to determine who’s to blame if something does go wrong.

One of the key issues is ensuring that drivers don’t become too relaxed. “As soon as someone takes his hands from the steering wheel, his reaction time increases,” says Thomas Mueller, who leads research and development of steering, braking, and driver-assist systems at Audi. “Taking [your] hands off the steering wheel sounds like a small issue, but it’s a big deal.”

The trajectory toward increased driver monitoring can be discerned in features found in some cars already capable of assisting with certain routine driving tasks. The Mercedes S-Class, for example, can follow the vehicle in front of it along a winding road at speeds above six miles per hour and below 37 mph, helping to relieve the driver in stop-and-go traffic. But the S-Class also monitors the driver’s attention using the steering wheel, identifying whether his hands have been removed, and sensing drift, which can be a sign of drowsiness or a lack of attention. 

More complete automation is on the way, with Tesla introducing automated highway driving to some Model S cars later this year through a software update, and Cadillac aiming to introduce an advanced form of cruise control capable of steering, braking, and acceleration sometime next year. Neither company has disclosed precisely how these systems will work, or whether they may involve increased monitoring of the driver.

There is, however, plenty of evidence to suggest that this new level of automation will change driving behavior. Those who have tested automated driving say it is surprisingly easy for attention to wander from the road (see “Self-Driving Cars Are Further Away Than You Think”).

The head of Google X, Astro Teller, said at the SXSW conference earlier this year that the company decided to do away with pedals and steering wheels in its latest prototype automated car because those behind the wheel of earlier versions quickly became complacent, and weren’t well equipped to retake control (see “Why Google’s Self-Driving Bubble Cars Might Catch On”).

Audi plans to launch an automated driving system for use in traffic jams next year, and automated highway driving sometime early in the next decade. Both systems will monitor the driver from a camera in the dashboard, which will track eye position and other behavior. “We need to make sure the handover time is as short as possible,” Mueller adds. While an automated system can activate at the flick of a switch, it can take many seconds for a person to regain the focus and awareness needed to retake control. “We will have a camera monitoring the driver, to see if he is jumping into the back seat, is falling asleep, or putting things between himself and the steering wheel—because you still have an airbag.”

The company does not plan to store any of this data, Mueller says. But it hopes to integrate digital distractions, such as smartphone alerts, with a car’s infotainment system, so that they can be more easily blocked if a driver suddenly needs to return to driving.

Legal concerns are also likely to encourage the trend toward greater driver monitoring. Robert Peterson, an expert on legal liability at Santa Clara University School of Law, says automation will complicate the existing picture. “If a car becomes increasingly automated, so you don’t have the responsibility for what the car does, then the liability is going to move from you, the driver—the operator—to the people in the commercial chain,” Peterson says.

A report issued by RAND Corporation in 2014 for policymakers concluded that over time automated driving may transform the insurance industry by transferring more liability onto manufacturers, and it warned that this might slow the development of the technology. For now, most major auto insurers remain mum on the subject.

The laws that allow automated driving to be tested in some states currently require that those vehicles have a black box recorder to capture data in the event of a crash. It’s conceivable that regulations could be introduced requiring data to be retained on both the car and the driver, according to Peterson.

“There may be some interesting questions surrounding the handoff,” he says. “Like, did it hand off in time to take over, and did you ignore the warning? Passing control between the driver and the autonomous mode is actually not very safe.”