SAN FRANCISCO, July 7

When it comes to dashboard displays that are more like smartphones, two things are clear: Customers want them, and automakers are intent on supplying them. But are they really a good idea?

Car companies answer with an emphatic yes. They say outsized dashboard displays that behave more like smartphones will boost revenue and attract buyers. And they also insist the new screens will make driving less dangerous, because of well-integrated voice controls and large touchscreens that will keep drivers from fumbling with more dangerous mobile phones.

But the increasingly elaborate screens have also sparked a broad debate about how much technology is appropriate in a car.

“I think they (the screens) raise serious public safety questions,” said Joe Simitian, former California lawmaker who spearheaded state’s laws on phone use while driving. “From a legislative standpoint, this is going to be something legislators struggle with for years to come.”

“You can’t be looking at a screen and be looking at the road at the same time,” said David Strayer, a professor of cognition and neural science at the University of Utah, who has written several studies on distracted driving. The screens ‘are enabling activities that take your eyes off the road for longer than most safety advocates would say is safe’.

His research shows that reading the average text message — a function some of the screens support — takes four seconds, far longer than what he considers safe.

For automakers and their customers, the souped-up screens are proving irresistible

But for automakers and their customers, the souped-up screens are proving irresistible.

In an Audi A3, for example, drivers who sync their phones with their cars can check for mentions of themselves on Twitter and see those tweets on their dashboards — although not their full Twitter streams. They can upload photos taken on smartphones and request mapping to the place the photo was taken. Text messages pop up on the dashboard, in addition to being read out loud.

“If you don’t provide something that is useful, people will just use their smartphones, and we all know that’s the biggest driver distraction there is,” said Mark Dahncke, a spokesman for Audi.

Up to now, dashboard technology hasn’t factored highly into most car buying decisions, but carmakers expect it to become increasingly important over the next three to five years.