The challenges facing the motor industry in meeting the 2013 deadline for all new vehicles to have digital radios were explored when the House of Lords Communications Committee questioned SMMT chief executive Paul Everitt.
By 2015, when the FM content will move to digital radio, all vehicles on the road should be equipped to receive the digital signal.
“A pan-European approach to the introduction of digital radio in vehicles is vital to a successful switchover," said Everitt.
"Every one of the 31 million vehicles currently on UK roads will be affected by the switchover, so coverage and content concerns must be satisfied, in addition to a means of converting existing FM radios to receive the digital signal."
The committee heard that satellite navigation relies on the FM signal for its traffic information.
"A significant investment will be required to enable the full functionality of these devices post-switchover," said Everitt.
"Government should clarify how a digital platform could support traffic information, as well as the feasibility of continuing transmission of traffic information on FM."
The SMMT has said broadcasters must engage with consumers to raise awareness of digital radio and the breadth of content on offer to increase demand for as-standard equipment in vehicles.