Issue details

During last year’s capital bidding round, Highways, Transportation and Waste submitted a bid for £31m to fund the resolution of 177 unfunded highway maintenance issues.  This bid was separate to maintenance backlogs reported in Kent County Council’s Asset Management Strategy documents.  The £31m bid related to a range of sites and issues that highway teams had identified had failed or will fail and which represented a significant safety or other risk to the business and are monitoring.  Funding of £7.52m for the highest priority 27 sites (high risk issues requiring intervention in the very short term) was approved and included in the capital budget, £3.495m for four sites in 2018/19, £2.925m for thirteen sites in 2019/20 and £1.1m for ten sites in 2020/21.

The £3.495m allocated for 2018/19 concerns three smaller drainage schemes (costing £295k), and the major renewal and preservation of the A256’s road surface between Whitfield and Sandwich at a cost of £3.2m and that is the subject of this key decision.

The A256 is an ‘Other Strategic’ road in our highway maintenance hierarchy.  It also forms part of our Resilient Highway Network, the portion of our 5,400-mile road network that is considered to be absolutely vital to maintaining economic activity and access to key services during extreme weather emergencies and other major incidents.  It is also likely to form part of the new Major Road Network (MRN) that the Department for Transport has recently consulted on.  (The MRN will be a new category of road between Highway England’s Strategic Road Network and Local Authorities’ local roads and this is being set up to put these important roads on a similar investment/improvement planning footing as motorways and trunk roads from 2021/22. Local Authorities will continue to be responsible for maintaining these roads and any funding streams are unlikely to be used for maintenance save major structural renewal.)  This road is also a key link between the channel ports and Manston in respect of interim lorry parking arrangements. In short, this road is vital to the economy of East Kent, an area of the county that is not otherwise well served by north-south roads.

As part of our regular mechanical condition surveys and safety inspections, we have identified that the existing road surface on the A256 between the A2 at Whitfield and Sandwich, and in particular the dual carriageway, is nearing the end of its serviceable life.  It has for several years been losing aggregate (a sign of bitumen losing its cohesiveness and strength) and its centre-joints are opening up which represents a hazard to motorbikes when they change lane. The majority of these serious defects are not obvious to untrained eyes that tend to focus on pothole formation.

The main risk if left untreated is that aggregate loss will continue and lead to the road surface rapidly failing which, given the high-speed nature of this road, would likely be catastrophic. In our professional judgement, we are very close to that eventuality now.  If that were to happen, we would need to consider measures such as reducing the speed limit, lane closures and possibility full road closures.  In addition, we would then need to replace the surface course for much/all of the road which would be prohibitively expensive.

However, we can apply a road surface preservation treatment called surface dressing to seal the existing surface, avoid further aggregate loss, restore texture and extend the life of this road by around ten years.  This treatment costs around £4 per square metre, compared to £25/35 per square metre for replacing the existing surface, and would be an appropriate treatment for much of the dual carriageway section.  However, other areas such as some of the roundabouts around Sandwich would not be suitable for this treatment and will need a new surface inlayed.

The Surface Treatment element of this solution needs to be delivered in August 2018.  That is because it can only be laid in warmer months but as the A256 is a high-speed road, it will need to be laid in peak treatment season to minimise any chance of premature failure.  If these works do not take place in August 2018, they would have to be delayed until August 2019, but it is likely that the road will deteriorate beyond being suitable for surface dressing by that time.

The Surface Dressing element will be delivered using established rates in our Term Maintenance Contract with Amey.  The remaining machine resurfacing works will be delivered later in the year under our recently awarded Road Asset Renewal Contract with Eurovia.