CLIENT: Arundel Arboretum
ROADWAYS ROLE: Principal Contractor, with full civil engineering and surfacing self-delivery including an in-house HBM / CBGM production
INTRODUCTION
Roadways was appointed to deliver Section 278 works for the new development access at Arundel Arboretum, forming the interface with the A27 Strategic Road Network (SRN) managed by National Highways.
For high-tier contractors in the UK, Section 278 works are often synonymous with unforeseen risk. Buried services, level misalignments, and rigid designs can quickly turn a routine access scheme into a budgetary and programmatic nightmare. However, as demonstrated by Roadways on this scheme in West Sussex, early contractor intervention is the ultimate hedge against these variables.
THE CHALLENGE
Roadways initial pre-start site audit identified two critical design flaws:
- the first was a level misalignment, which would have resulted in the new access road tying into the A27 approximately 150 mm below the required level if constructed as designed.
- the second was an excessive pavement construction depth of approximately 810 mm. While the level discrepancy presented an immediate compliance issue, the construction depth introduced a broader and more significant delivery risk.
At this depth, the scheme would have been exposed to known and unknown underground services, including live BT infrastructure and a medium-pressure gas main. It would also have driven unnecessary excavation, increased muck-away and imported material volumes, and extended programme duration without delivering proportional structural benefit.
If left unaddressed, these issues would likely have manifested later in the programme during the tie-in to the A27, at which point corrective works would have required re-excavation, aborted shifts, remobilisation of crews and extended disruption on the live network.
Rather than progressing and managing the consequences later, Roadways took immediate and controlled action. A formal technical query was raised through the appropriate governance channels, with both the client and National Highways informed of the issue, associated risks and potential impacts.
SOLUTIONS
The revised design introduced 250 mm of Hydraulically Bound Material (HBM / CBGM) as a cement-bound road base, overlaid with 200 mm of asphalt. This reduced the total construction depth to approximately 450 mm – a reduction of around 460 mm compared with the original design.
The solution not only significantly reduced exposure to underground services and improved constructability, it also incorporated additional drainage measures to intercept surface water and prevent runoff onto the A27.
Crucially, the revised design remained fully compliant with the Specification for Highway Works (Clause 948), with no departures or changes to adoption responsibility or process.
Roadways’ ability to respond quickly and confidently was underpinned by self-delivery model and in-house materials capability.
HBM was produced using recycled road planings, crushed concrete and cement, under controlled batching processes, supported by independent laboratory testing and quality assurance.
Delivery, laying, compaction and curing were all managed by Roadways’ trained teams, ensuring full control of sequencing, logistics and quality from production through to placement.
Materials were supplied from Roadways’ South East facility, enabling efficient delivery and repeatable application across the region.
This integrated approach reduced interfaces, improved responsiveness and ensured that engineering decisions could be implemented without delay once approved.
PROGRAMME & COMMERCIAL
- Reduced time on site by 30%
- Reduced cost by 40%. By reducing excavation depth by 460 mm, lowering labour, plant, muck-away, disposal and imported material requirements
- Improved programme certainty: resolved the design issues before work commenced
- Avoided abortive cost, risk of late-stage redesign, re-work, remobilisation and service-damage exposure
- Network cost exposure: lowered TM requirements and lane rental costs
HS&E, CARBON PUBLIC IMPACT
- Eliminating risks: reduced exposure to underground services, including live medium-pressure gas and telecommunications infrastructure
- Reduced site exposure: cut time on site by approximately 25%, reducing the number of people, plant movements and live interfaces required
- Lower environmental impact: reduced excavation volumes, haulage, plant use and fuel consumption
- Lower embodied carbon: achieved up to 70% lower embodied carbon through material efficiency, recycled HBM / CBGM and avoidance of rework
- Reduced public disruption: reduced traffic management exposure and disruption risk at the A27 Strategic Road Network interface
Across this scheme, Roadways applied a simple principle: identify risk early, remove it properly, and avoid transferring problems downstream.
By stopping works before incorrect levels and excessive construction depth became embedded, and by delivering a standards-compliant redesign that addressed the root cause rather than the symptoms, Roadways ensured the scheme could be delivered once, correctly and without avoidable intervention on the live network.
ABOUT ROADWAYS
Roadways is a highways and civil engineering contractor with Tier 1 principal contractor and full self-delivery capability, operating across the South East.
We deliver cost effective, quality and sustainable highways maintenance, resurfacing, civil engineering and road recycling schemes for National Highways, local authorities, Tier 1 contractors and private clients. Roadways designs, produces and installs its own materials — including Cold bitumen emulsion based asphalt and Hydraulically Bound Materials (HBM / CBGM) — giving direct control over quality, programme certainty and commercial risk.
By applying the operative Specification for Highway Works more intelligently, Roadways delivers lower-risk, specification-compliant infrastructure without departures or experimental methods.