US carmakers are on a collision course with a federal government agency after rejecting proposed safety guidelines governing the use of new automotive communication systems.

One increasingly popular feature of so-called “smart cars” is a dashboard docking system for mobile phones and tablets. But the National Highway Traffic Safety Administration argues these systems should enable certain functions – such as texting and social network access – only when the car is stopped.

David Strickland, NHTSA administrator, said restrictions on dashboard communications systems were warranted. “The latest research tells us that [these systems] requiring drivers to take their hands off the wheel or eyes off the road are the most dangerous,” Mr Strickland told the Financial Times.