Highways England revealed a £317m “pinch point” programme often resulted in benefits for rush hour journeys after one year but any gains were outweighed by delays at other times of day.
Longer journey times during off-peak periods cost £5.6m, compared with shorter journeys at peak periods which had a benefit worth £5.1m.
Nearly half of the schemes with an objective to cut journey times failed to do so, findings the RAC said were “very disappointing”.
Nicholas Lyes, the RAC’s head of roads policy, said: “It’s very disappointing that Highways England’s work to tackle pinch points on its road network has not been as successful as had been hoped.
“While congestion has been reduced at peak times of the day, unfortunately many schemes have seen increased traffic at off-peak periods, mostly due to traffic lights being introduced.
“Luckily, it seems as though there are some simple steps that can be taken to improve the worst of these new off-peak traffic flow issues, such as changing signals to work part-time instead of full-time.
“It is also important to realise that this work was not just about reducing congestion and that many schemes have seen small reductions in the number of road casualties.”
Highways England listed the most expensive projects that resulted in increased congestion as being a £2.5m scheme at the junction of the A5 and A49 in Shrewsbury, Shropshire; £1.5m works at junction 23 of the M6 in Newton-Le-Willows, Merseyside, and a £1m project at junction 9 of the M40 junction in Wendlebury, Oxfordshire.
Highways England published the findings in a report after evaluating the first-year impact of nearly half of the 119 ‘pinch point’ schemes on England’s motorways and major A roads.
The document mentions the widening of the M18 at junctions 2 and 3 from two lanes to three in South Yorkshire, stating that it “does not show any specific benefits from adding capacity to the northbound carriageway”, but that this was because it was too early to measure increased traffic generated from the development of a new link road connecting south Doncaster with Doncaster Sheffield Airport.
The pinch point programme was established in 2011 to relieve congestion, stimulate economic growth and improve safety, and was largely delivered by Highways England’s predecessor, the Highways Agency.
Highways England said its report showed that overall, the pinch point schemes had been successful at tackling congestion at the busiest times and improving safety.
A spokesman said: “This useful insight is helping us develop improved appraisal methods for small-scale schemes, which in turn help us deliver improved benefits to people using our motorways and major A roads.
“Meanwhile, we are considering a range of options to improve journeys by using traffic signals which respond to traffic flows.”
Recent government figures show motorists suffered a 3.9 per cent increase in delays on major roads last year.