The new study from the Road Users' Alliance shows that Britain has more cars per motorway mile than any other EU-25 nation.
Unable to compete with countries such as Germany and France, Britain’s motorways are the bottom of the league with less developed nations such as Lithuania, Slovakia and Hungary.
Congestion and unreliable travel times affect the UK's economic competitiveness and quality of life, said the report.
The figures are to be revealed in a presentation by the RAC Foundation's director, Edmund King, at The Transport Times conference in London today.
In his presentation, Mr King will also highlight the fact that the UK has lower car ownership rates than many European nations but worse congestion.
Mr King said of the report: ‘Roads in the UK are essential for 92% of passenger traffic and 88% of our freight.
‘This reliance on the road network will continue even if public transport is radically improved.
‘We need road improvements but we also need to question when and where we travel.’