The Office of Rail and Road (ORR) has told Highways England to “learn lessons” about the importance of pre-construction work after a major road project was delayed.
Ground investigations for the A21 Tonbridge to Pembury dualling scheme were not as comprehensive as they could have been, according to the ORR after it visited the site.
This resulted in a delay to the project – the dualling scheme is now due to finish in the summer, having been pushed back from the spring.
“Our biggest takeaway was the importance of preconstruction surveying and investigation, particularly in such challenging areas,” said Highways Directorate head of economics and policy David Hunt in a blog post.
“We will expect Highways England to learn these lessons for future projects.”
The project is tackling a bottleneck on the A21, on the main link road from the M25 to Hastings.
A 4.8km stretch of single carriageway attracts more than 35,000 vehicles per day – more than its capacity – and there is no merging provision for side roads and properties joining the carriageway.
Contractor Balfour Beatty is dualling this stretch of road to ease congestion and much of the earth moving and carriageway construction is now complete.
But the ground investigations were not as comprehensive as they should have been as the route covers a sensitive woodland site, making investigations difficult. As a result, more contaminated land was found than expected, and the site geology was found to be more complex. Wildlife considerations also contributed to the delays – protected species such as dormice could only be moved at certain times of the year.
“We have made a vast amount of progress on the scheme and have been protecting the environment,” said a spokesperson for Balfour Beatty.
“It has taken us longer than we originally planned to get to this stage due to the amount of contaminated soil we have discovered, around 35,000t, which has meant a significant amount more work.”
More than half of the 112 schemes in Highways England’s Road Investment Strategy (2015 to 2020) focus on upgrades to major A roads, where delays are common and traffic is often in close proximity to residents and natural habitats.
The ORR holds Highways England to account over its £15bn road schemes and site visits form part of its work. New Civil Engineer has contacted Highways England for a response.