Hindhead Tunnel

Hindhead Tunnel

South portal of the Hindhead Tunnel. October 2012
Overview
Location	Hindhead, Surrey, UK
Status	Active
Route	A3
Operation
Work begun	January 2007
Opened	29 July 2011
Owner	Highways England
Operator	Highways England
Technical
Length	1,830 m (1.14 mi; 6,000 ft)
No. of lanes	Two in each tunnel
Operating speed	Speed limit: 70 mph (113 km/h) Design speed: 120 km/h (75 mph)

Speed limit: 70 mph (113 km/h)

The Hindhead Tunnel, opened in 2011, is part of the 6.5 km (4.0 miles) dual-carriageway Hindhead bypass that replaced one of the last remaining stretches of single-carriageway on the 68-mile (109 km) A3, the London to Portsmouth road. The bypass was constructed to improve road safety, reduce congestion and improve air quality. At 1,830 metres (1.14 miles; 6,000 feet) in length, the tunnel is the longest non-estuarial road tunnel in the United Kingdom, and takes the road beneath the Devil's Punch Bowl, a Site of Special Scientific Interest.

A naval dockyard has existed in Portsmouth since at least Tudor times, giving significant importance to the road linking that city with London. The original 73-mile (117 km) route skirted the north-western limits of The Weald climbing to the summit of Gibbet Hill close to Hindhead. In 1826 the road, which in the 1920s was designated as the A3, was rebuilt around the Devil's Punch Bowl to ensure that the gradient was no more than 5%.

By the start of the new millennium most of the A3 had been dualled; of the route from Southfields to Havant, only the section that passed through Hindhead and the Devil's Punch Bowl was still single carriageway. This section, which passed through an Area of Outstanding Natural Beauty (AONB), operated at or above capacity for much of the day and had an accident rate 40% higher than the national average for that class of road.

By 2000 the A3 between Southfields and Havant had been built to dual carriageway standards for its entire length apart from the 5.5 km (3.4 miles) Hindhead section (there are still sections of single carriageway within London and Portsmouth). The termini of the northern and southern sections of dual carriageway were at altitudes of 180 m (590 ft) and 190 m (620 ft) above sea level respectively and the single carriageway linking them followed a winding route around the Devil's Punch Bowl, reaching an altitude of 260 m (850 ft). The Hindhead Tunnel project shortened the route by about 300 m (980 ft) and routed the road through a tunnel whose northern and southern portals are at altitudes of 190 m (620 ft) and 200 m (660 ft) above sea level respectively.