DETROIT - The government is asking automakers to put stronger limits on drivers' interaction with in-car touch screens in an effort to curb distracted driving.

U.S. traffic safety regulators unveiled guidelines Tuesday that would restrict the amount of time it takes to perform both simple and complex functions on a car's entertainment and navigation systems.

Regulators also want to ban manual text entry and display of websites, social media, books and other text distractions while the car is moving.

"Distracted driving is unsafe, irresponsible. It can have devastating consequences," said Transportation Secretary Ray LaHood, who announced the guidelines along with National Highway Traffic Safety Administration Administrator David Strickland.

LaHood and Strickland told reporters on a conference call that NHTSA has determined that over 3,000 people were killed in crashes that involved distracted driving in 2011 and more than 387,000 were hurt.

The guidelines are voluntary for automakers and will be phased in over three years.

Strickland said NHTSA has had success with voluntary guidelines and would consider giving automakers incentives to comply.

But Clarence Ditlow, executive director of the Center for Auto Safety, a frequent NHTSA and auto industry critic, said the guidelines will do little to halt distracted driving.

"We've tried voluntary. Voluntary doesn't work," he said.

NHTSA based the new guidelines on a study it conducted on distracted driving. The results showed that tasks requiring drivers to look at touch screens or hand-held devices increase the risk of getting into a crash by three times. Texting, web browsing and dialing a phone were the tasks that kept drivers' eyes off the road the longest.

However, the study did not find an increased risk of a crash from just talking on a cellphone.

The new guidelines limit simple tasks to two seconds. They also restrict the time allowed for complex tasks to 12 seconds, but do not limit the number of times a driver can touch a screen. The decision on whether a screen would freeze or shut down after 12 seconds would be left to automakers based on their own research, NHTSA said.

The auto industry's current guidelines, which are a decade old, allow drivers to read text and perform other more complex tasks while cars are moving at less than 5 mph, Strickland said. Systems now are designed so multiple-step tasks take 10 or fewer screen touches for a total of 20 seconds with a driver's eyes off the road. But the devices won't turn off or stop a driver from doing something that takes longer than 20 seconds.

The new guidelines "will help us put an end to the dangerous practice of distracted driving by limiting the amount of time drivers take their eyes off the road," Strickland said.

The Alliance of Automobile Manufacturers, a group representing 12 large car makers, is worried that drivers will simply turn their eyes to something else: their mobile devices.

Gloria Bergquist, spokeswoman for the alliance, said a mobile device, with its smaller buttons and screens, "wasn't designed for use while driving a vehicle." She said guidelines for mobile devices should be proposed at the same time as those for in-car equipment, which is designed to be used while driving.

NHTSA said it will address mobile devices and voice-activation technology in the next phases of guidelines. But it encouraged mobile device makers to adopt recommendations from Tuesday's guidelines "that they believe are feasible and appropriate for their devices."

The guidelines cover any manufacturer-installed device that a driver can see or reach, but they do not affect video screens located behind the front seats.

Navigation maps that show movement as cars travel would still be allowed, as would the input of preset destinations, Strickland said. But a car would likely have to be stopped for a driver to manually type in an address.

NHTSA said more research is needed to decide if the guidelines should cover heavy trucks and buses.