Highways Agency

Chapter 2 Maintaining the Network

The Agency's highest priority

The estimated proportion of the network likely to require maintenance in the next year

Between 7 and 8%

7.1%

Night maintenance works minimises disruption to road users.

The Agency was responsible for some 9,805 km (6,128 miles) of motorways and trunk roads in 2000/01, including about 16,000 structures such as bridges and gantries. Maintaining this national asset is its highest priority. This involves a wide range of activities from replacing worn-out road surfaces and repairing safety barriers, to responding to incidents (e.g. accidents or a spillage) to ensure the safety of road users and when necessary clearing debris so the road can re-open as quickly as possible.

In 2000/01 the Agency spent around half (some £722 million) of its total programme budget of £1,418 million on maintenance. This kept the network safe and close to optimum condition, meeting the Agency's target of ensuring no more than 7 - 8% of the network remained in need of maintenance at the end of the year. In order to keep disruption to its customers to a minimum, wherever possible the Agency carried out road works outside the busiest times, suspending them when major events, such as the FA Cup Final, caused extra demand.

Coping with bad weather is an important part of the Agency's maintenance activities. October and November 2000 saw record-breaking rainfall and widespread flooding across the country. Though the Agency's road drainage systems coped well with the large quantities of rainwater running off the road, they had difficulty coping with additional water soaking in from the saturated surrounding land. This resulted in some roads having to be closed due to local flooding. The Agency is investigating techniques to improve the way it deals with these sorts of problems in future. Despite the heavy snow and ice that affected most parts of England over Christmas and the new year, the Agency successfully kept all of its motorways and most of its trunk roads open.

In partnership with British Waterways, the Agency filled in a strech of the Birmingham Fazeley Canal to carry out maintenance work on the Oldbury Viaduct under the M5

The use of new technology continues to play a key role in improving the way the Agency carries out its maintenance work, reducing the need for future maintenance and keeping disruption to traffic to a minimum. For example, the use of satellites to carry out geological surveys has helped the Agency avoid the need for costly and disruptive investigations into rock faces and other difficult-to-access areas alongside busy motorways and trunk roads. The condition of rocky outcrops next to the M6 at the Lune Gorge in Cumbria is now surveyed using satellite-based cameras.

The Agency also uses a variety of high-tech systems to gather information on its network, which help it to plan its work more effectively and target maintenance where it is most needed. Methods include the use of specialist high-speed survey vehicles and computerised systems to collect, store and analyse information on the condition of the network. This work is already showing real benefits and will continue to be developed over the coming years.

Case study : Protection against salt corrosion

The Agency's reinforced concrete motorway bridges are weather-resistant, even in exposed areas like the Lake District. However, over the 30 years that the M6 around Penrith has been operational, some of the large quantities of de-icing salt used to keep it open to traffic in the winter months has penetrated into several of the structures and has caused the steel reinforcement to corrode and the concrete to deteriorate.

Six bridges between junctions 38 and 40 of this stretch of the M6 were badly affected by this, and also needed strengthening to cater for vehicle impacts. To avoid the use of costly traditional procedures, which would have caused major disruption to traffic, the Agency carried out an innovative £820,000 scheme to repair these bridges and strengthen their supports.

This innovative project used an electrochemical process to reduce the high concentrations of salt in the concrete. The supports were then wrapped in fibre-reinforced polymer sheets which were bonded to the concrete surface. These will prevent further absorption of de-icing salts into the concrete and strengthen the supports.

Bridge protection against salt corrosion on the M6