The RAC Motoring Foundation has identified almost 4,600 miles of roads without any mobile phone signal.
It says the stretches of roads in 49 local authority areas represent 2% of the total throughout Britain.
They include the whole of the A93 in Scotland, the A149 in East Anglia, the A494 in Wales and the A591 in Cumbria, according to the study based on official Ofcom data.
A further 28,975 miles of road (12%) have only partial 2G coverage meaning there are many areas where some but not all phones will receive a signal depending on the service provider.
Steve Gooding, director of the RAC Foundation, said mobile phone coverage was needed not just in case of an emergency but also to download travel information.
'Most of us like to think we are always just a mobile phone call away from help but even in a crowded, high-tech country like Britain the reality is somewhat different.
'Our work shows there are thousands of miles of road along which you would not want to break down or have an accident.'
