| South portal of the Hindhead Tunnel under construction. | |
| Overview | |
|---|---|
| Location | Hindhead, Surrey, UK |
| Status | Active |
| Route | A3 |
| Operation | |
| Work begun | January 2007 |
| Opened | 29 July 2011 |
| Owner | Highways Agency |
| Operator | Highways Agency |
| Technical | |
| Length | 1.2 miles (1.83 km) |
| Number of lanes | Two in each tunnel |
| Operating speed | Speed limit: 70 mph (113 km/h) Design speed: 120 km/h (75 mph)[1] |
The Hindhead Tunnel is a road tunnel that opened (southbound and northbound) on 29 July 2011 as part of the new Hindhead bypass for the A3 road in Surrey. It forms part of the 4 mile[2] (6.7 km)[3] dual-carriageway being built to replace the last remaining stretch of single-carriageway on the 68-mile (109 km) London to Portsmouth road.[2] The bypass is intended to improve road safety, reduce congestion and improve air quality.[4][5] At 1.2 miles (1.83 km) long,[6][Note 1] the tunnel is the longest non-estuarial road tunnel in the United Kingdom,[4] and takes the road beneath the Devil's Punch Bowl, a Site of Special Scientific Interest.[4]
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The tunnel is part of a bypass scheme that replaces the original A3 which followed a route that dates from 1826 through Hindhead, the Devil's Punchbowl and adjacent areas.[7] The original route was single carriageway through the Devil's Punchbowl area, which is of outstanding natural beauty. The route itself was at or above capacity for much of the day and had an accident rate that was 40% higher than the national average for that class of road.[1]
The need for improvements to the A3 through Hindhead had been recognised for many years with a route study being undertaken between 1970 and 1976.[8] In 1983 some nine alternatives for the A3 were investigated by the Department for Transport, but assessment showed that only one which went around the north and west side of the Punch Bowl (the "Red Route"), crossing the Smallbrook Valley was viable.[8] A public consultation on the route met with opposition and two alternatives were suggested both of which drew less support than the proposed route which in 1988 became the preferred route.[8] Subsequent environmental surveys showed that this route would have substantial adverse impacts resulting in the proposal to adapt an earlier scheme by including a tunnel to avoid the most sensitive parts of the route. The scheme entered the Government’s targetted programme of improvements in 2001.[8]
A public inquiry was held in September 2004 to hear objections and to consider alternatives to the proposal. Among the alternative proposals was one for a surface route following a more westerly line that would avoid building a tunnel (an adaptation of the "Red Route"). Despite being significantly more expensive than building a surface road, a tunnel was preferred after two alternative surface schemes were rejected on environmental grounds.[1][9][8] The decision to put part of the road in a tunnel has meant that at a cost of about £142,000 per yard (£155,000 per metre) the underground portion of the new road will be the second most expensive road in the UK per mile, after Limehouse Link tunnel.[9]
Advance works started in January 2007, and main construction works, including the tunnelling, started in 2008.[2]
During an open day on 14 May 2011, just under 7,000 pedestrians were able to walk the full length of the tunnel before it opened to traffic in July 2011.[10] At the open day, local music groups performed at the north end of the tunnel. These included the Haslemere Town Band playing the Devil's Punch Bowl March which was composed for the occasion by 16-year-old band member Eric Foster.[11]
On 19 July 2011 the Highways Agency announced that the southbound tunnel was due to open to traffic on 27 July 2011, and that the northbound tunnel would be opened a few days later.[12] The opening ceremony, to which the public was not invited for safety reasons, was performed by the Secretary of State for Transport Philip Hammond.[12] The final opening for northbound traffic occurred on 29 July 2011,[13] two days ahead of schedule.
Twin tunnels were bored from each end by excavating about a yard (1 m) per day using diggers, then spraying the walls with concrete. On 26 February 2009, engineers met at the breakthrough point.[14] Each tunnel, which has an approximate excavated diameter of 38 feet (11.6 m) and an 8 inches (200 mm) primary shotcrete lining[15] incorporates a 24 feet (7.3 m) wide carriageway with a 16.5 feet (5.03 m) high traffic gauge and 4 feet (1.2 m) wide verges on either side. Emergency interconnecting cross passages are located at 109 yards (100 m) intervals to facilitate movement of pedestrians between tunnels in case of emergency.[3]
Ancillary works include a deep cutting to the south of the tunnel with a new junction for Hindhead and Hammer at its southern end. An equestrian and pedestrian bridge, the Miss James Bridge, crosses the cutting between tunnel and junction, and includes heathland planting to link the habitats on either side of the cutting.[16]
A visitor information leaflet distributed at the walkthrough listed the following facts about the tunnel work:[17]
According to reports in September 2011, the tunnel is being used by "wealthy young drivers" in powerful sportscars to perform time trials. They state that cars such as Lamborghinis, Ferraris and Aston Martins are regularly seen using the tunnel as a racetrack at night.[18][19]