At General Motors' technical center in Warren, Michigan, many volunteer drivers tested real Cadillac Lyriq EVs.

They also tested other GM models inside a simulator.

The simulator is a 360-degree world.

It measures eye movement, heart stress and sweating.

GM uses it to study human drivers.

It does not just study the vehicle technology.

The simulator helps GM and other automakers test advanced driver assistance systems.

These systems are called ADAS.

These systems already offer automatic emergency braking.

They offer blind spot warnings and lane-centering assist.

They let drivers go "hands-free" at certain times.

This happens mainly on highways.

Automakers expect these systems to become very advanced.

Then drivers can take their hands off the wheel.

They can take their eyes off the road.

Sam Abuelsamid is vice president of market research at Telemetry.

He said "eyes off" is the turning point.

At that point, consumers will pay for the feature.

He said it gives drivers back time.

They no longer have to watch the road.

GM says its eyes-off version will be possible by 2028.

Then it launches the next Super Cruise on the Cadillac Escalade IQ.

Abuelsamid said 2028 is a broad timeline.

Many companies target similar systems at highway speeds.

GM has sold Super Cruise since 2017.

It is hands-free but not self-driving.

It works on over 630,000 roads in the U.S. and Canada.

Tyson Becker is a GM executive director.

He said drivers can take their hands off the wheel.

They can keep their eyes on the road.

This makes the commute less stressful.

More than 20 GM models now have the technology.

These models are across Cadillac, GMC, Buick and Chevrolet.

Becker said GM's goal is a next generation of Super Cruise.

It allows safe, eyes-off driving.

Predicting unexpected road scenarios is very hard.

It is one of the hardest parts of autonomous technology.

A dog, deer or child could run into the road.

A construction zone could appear suddenly.

Simulation, data collection and artificial intelligence help with this.

In GM simulations, drivers face computer-generated highway and city scenarios.

These include other "humans" and road signs.

Maureen August is a senior manager at GM Research & Development.

She said GM wants to cover anything customers could experience on the road.

GM watches heart rate, stress, eye direction and attention.

It watches from a nearby control room.

One effective test is having drivers play Candy Crush.

August said this engages them.

Then it requires pulling them away.

After driving, participants are asked how they felt.

They are asked if the system was intuitive.

GM also looks at comfort, convenience and trust.

It looks at how many seconds a driver needs to take full control.

August said GM wants drivers to respond well to alerts.

GM also wants the vehicle to do what it can.

This happens when drivers feel comfortable.

Ford's BlueCruise is another notable hands-off system.

It is available on over 130,000 miles of certain North American roads.

Tesla calls its technology "Full Self-Driving."

But it still requires human oversight.

No passenger vehicles in production currently offer eyes-off technology.

But some tech companies run autonomous robotaxi services in select cities.

Experts say regulatory hurdles remain.

Abuelsamid said there is little real regulation today.

So automakers seek approvals state by state.

He said it remains to be seen where GM can offer its eyes-off system in 2028.

Automakers are racing toward advanced tech.

They want to attract consumers and earn subscription fees, he said.