A warning has been issued that major road upgrades could be scrapped because they do not represent value for money.
Sixteen upgrades could be at risk, a Whitehall spending watchdog has warned.
The schemes are part of an £11.4 billion investment in motorways and major roads which must be reconsidered by the summer to ensure it is deliverable and affordable, the National Audit Office said.
In 2014, the then coalition government announced details of a five-year Road Investment Strategy featuring 112 major schemes to begin between 2015 and 2020, such as smart motorway upgrades and converting single-carriageway A-roads to dual carriageways.
But government-owned Highways England, which is responsible for maintaining and improving major roads, has identified 16 projects which could be cancelled, delayed or redesigned to ensure more efficient use of taxpayers' money, the NAO said.
None of the projects at risk have been identified, but the overall plan for road improvements includes projects such as a tunnel at Stonehenge, upgrading the M1 to a smart motorway around Sheffield and Rotherham, and improving electronic signage, emergency roadside telephones and CCTV cameras on the M11 between Stansted Airport and Cambridge.
AA president Edmund King said drivers across the country will be frustrated to learn that 'even after clear promises were made, upgrades to heavily congested roads could be delayed or scrapped altogether'.
He added: "The public should be told which of the 16 schemes have stalled so that they know if they are stuck on a road to nowhere."
A Department for Transport spokesman said: "This Government is taking the big decisions for Britain's future, and we are investing a record £15 billion on road schemes which will cut congestion, speed up journeys, and boost the economy across the country.
"As this report acknowledges, we have made significant progress in managing our major roads more efficiently, and we are confident Highways England will deliver safe and reliable roads that deliver value for money for the taxpayer.
"We will consider the findings of this report."