Communications Minister Ed Vaizey will today announce the new Government is to press ahead with a switchover to digital radio - but will shy away from setting a date.
He will say the FM signal should be switched off when "the weight of public opinion" dictates.
A provisional target date of 2015 had been identified by the outgoing Labour government but Mr Vaizey will say a decision will not be made until half of all radio listening is via digital sources.
For many drivers it will mean the prospect of buying new radios or using conversion kits as digital radios are not often fitted as standard.
Figures from radio industry audience body Rajar show that around 24% is currently via digital.
Mr Vaizey is to publish a Digital Radio Action Plan encouraging listeners to make the switch.
This will involve building DAB coverage, which only covers about 90% of the population, and a cost-benefit analysis of the changeover.
Speaking at the Intellect Digital Home Conference, Mr Vaizey will say: "Listeners need to be persuaded that the content on offer is compelling, that the quality is high and that digital radios, at home or in the car, are affordable and have listening quality that is at least as good as FM.
"I am not setting a date. The industry believes 2015 is an achievable target date and we will work to support that ambition. And when the weight of public opinion is behind it, with more than half of all radio listening digital, then we can take the decision on when the country will be ready for switchover."
New research to be published later today claims to show broadcasting digitally is more energy efficient than analogue. It suggests that transmitting Classic FM nationally via DAB uses less than 7% of the electricity needed to transmit it via FM.
Earlier this week the BBC Trust rejected proposals to close down the digital station 6 Music which had been put forward by BBC director general Mark Thompson.Reuse content