The National Highway Traffic Safety Administration, part of the Department of Transportation, said electronic functions that compel drivers to look away from the road for more than two seconds -- to do such things as Web searches, social networking, texting and navigation that requires the input of addresses -- are too dangerous when cars are moving.
The agency recommended these functions be inaccessible to front-seat passengers "whenever the vehicle's engine is on and its transmission is not in 'Park,'" the agency said in guidelines published in the Federal Register, Washington's official journal containing public notices of government agencies.
The non-binding guidelines also call for disabling 10-digit phone dialing.
"Distracted driving is a dangerous and deadly habit on America's roadways," Transportation Secretary Ray LaHood said in a statement.
"These guidelines are a major step forward in identifying real solutions to tackle the issue of distracted driving for drivers of all ages," he said.
Thursday's announcement -- the first of its kind in the United States -- followed December's recommendation by the U.S. National Transportation Safety Board to ban the use of cellphones and hands-free electronic devices.
The NTSB is responsible for promoting traffic safety and investigating accidents.
NHTSA's preliminary recommendations are subject to a 60-day public commenting period, followed by final NHTSA guidelines.
Public hearings on the proposal are to take place in Los Angeles, Chicago and Washington next month, the agency said.