Traffic congestion will rise by 37% if the current "minimal levels of investment" in roads continues for the next 15 years, a report has said.
By 2025, drivers could be wasting 656 million hours a year - the equivalent of 75,000 years - sitting in traffic jams, the Road Users' Alliance (RUA) added.
"Under-investment in the strategic road network has left the UK with a transport system which is uncompetitive, congested, vulnerable to incident and inadequate to meet the future needs of the economy," the report concluded.
The RUA said that the UK's investment in new motorway capacity was among the lowest in Europe, with no new motorway miles being created in 2007 and 2008.
It added that while £47 billion a year was collected in road user taxes, only £4 billion was invested in new road capacity;
The survey also revealed that the major road network grew by 1% between 1998 and 2008, but had to cope with traffic growth of almost 10%.
Travel by car remained the most popular form of transport, with 92% of Britain's passenger transport taking place by road and 70% of commuting and business journeys made by car.
RUA director Tim Green said: "Road users have for too long been regarded as wallets on wheels, providing an endless stream of revenue for the Government to spend on anything except the road network.
"Hard choices face whichever party leader finds himself in Downing Street after the election. Will limited funds be spent on rail, which moves fewer than 10% of UK passengers, or invested in the transport mode which makes the biggest contribution to the UK's prosperity and quality of life - the road network?"