US transport safety officials have proposed guidelines to limit driver distraction from gadgets built into cars.
The planned voluntary rules would cover "integrated electronic devices, including mobile phones".
Officials want distracting functions to be disabled when driving.
In 2010, US figures suggested that "distraction by a device or control integral to the vehicle was reported in 26,000 crashes".
The new proposals include goals to reduce the amount of inputs required to operate a device - the number of buttons to push - and reducing unnecessary visual information.
There are also guidelines requiring one-handed operation and a two second limit on "off-road glances" - the time spent looking at the device.
The National Highway Traffic Safety Administration (NHTSA) also wants built-in gadgets the driver can use to turn-off non-essential functions while the car is moving, and keep them disabled until the car is parked.
In particular they want to prevent manual texting, use of the internet/social media, entering addresses into sat navs and dialling long phone numbers.
Displaying more than 30 characters of text not related to driving should also be prevented, it says.
Electronic warning systems would be exempt from the rules, the NHTSA said.
The first phase of the plans only apply to built-in devices.
However, the NHTSA said that in later phases it might issue further guidelines on the use of "devices or systems that are not built into the vehicle but are brought into the vehicle and used while driving".
This could include "navigation systems, smartphones, electronic tablets and pads, and other mobile communications devices".
Official figures suggested that in 2010 electronic devices were involved in 47,000 distraction-related crashes.
NHTSA administrator David Strickland said consumers wanted more "tools and conveniences" but said the guidelines would help carmakers "develop electronic devices that provide features consumers want - without disrupting a driver's attention or sacrificing safety".
The NHTSA is currently consulting on the first phase of the proposals.