An analysis of 54 of 119 projects introduced more than three years ago under the £317M Pinch Point Programme reveals that journey time benefits generated during peak times were not being sustained across a 24 hour period. This was predominantly a consequence of using traffic light signals around the clock, it is said.
Reducing congestion during the busiest periods – or on severely delayed routes – was a specific objective in nearly nine in 10 of projects evaluated. “To a great extent, these benefits have been realised,” the study says. However it adds that journey time benefits experienced by road users during peak times “have been offset by slower journeys during off peak periods, which in turn has reduced the net benefit of schemes across the sample”.
Pinch point schemes evaluated achieved £5.1M benefit during the morning and evening peaks, but produced net dis-benefits of £5.6M at other times.
Examples cited include a scheme on the M27 at junction five near Southampton Airport, which included widened approaches and additional traffic signals. Benefits have been seen in the afternoon peak and for movements from the airport, it says, but overall the adverse impacts outweighed the gains.
The study recommends that scheme appraisals need to consider the impact of interventions “across all 168 hours of the week, not just the 10-30 peak hours in a week”. It adds that scheme designs need to better consider how to “mitigate the downsides while maintaining the upsides”.
RAC head of roads policy Nicholas Lyes 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.
“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.”
A Highways England spokesman said the report shows that overall the pinch point schemes were successful at tackling congestion at the busiest times and improving safety.
“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,” the spokesman added.More Articles by Chartered Institution of Highways & Transportation (CIHT) ...