M3 motorway

M3 motorway. The M3 motorway is a major motorway in southern England, connecting the capital city of London to the important port city of Southampton. Running for approximately 59 miles (95 kilometres) through the counties of Hampshire, Surrey, and into Greater London, it forms a vital corridor for traffic between London and the southwest of England. The motorway significantly alleviates congestion on the historic A30 road and provides a strategic link to other key routes like the M25 motorway and the M27 motorway.

Route

The motorway begins at its northeastern terminus at Sunbury-on-Thames, where it diverges from the A316 road near the junction with the M25 motorway at Junction 12. It heads southwest, passing to the north of Woking and skirting the perimeter of the Army Training Centre Pirbright. The route continues past Farnborough, home to the Farnborough Airshow, and Basingstoke, a major commercial centre. It traverses the scenic North Wessex Downs Area of Outstanding Natural Beauty before meeting the A303 road near Winchester. The final section runs past Eastleigh to its terminus at Southampton, where it merges with the M27 motorway near Southampton Airport.

History

Planning for a motorway to relieve the heavily congested A30 road began in the 1960s. The first section, a bypass for Basingstoke, opened to traffic in 1971. Construction progressed southwest, with the Winchester bypass section, which included the notable Twyford Down cutting, opening in 1994 after considerable controversy and protests from environmental groups like Friends of the Earth. The final extension from Compton to the M27 motorway at Southampton was completed in 1995, marking the motorway's full opening. The controversial cutting through Twyford Down remains a significant case study in UK road protest history.

Junctions

{| class="wikitable" |- ! County ! Junction ! Destinations |- | Greater London/Surrey | J1 | Sunbury-on-Thames, A316 road |- | Surrey | J2 | M25 motorway, Heathrow Airport |- | Surrey | J3 | Woking, Lightwater |- | Hampshire | J4 | Farnborough, Fleet |- | Hampshire | J5 | Hook |- | Hampshire | J6 | Basingstoke (North) |- | Hampshire | J7 | Basingstoke (South) |- | Hampshire | J8 | A303 road, Andover |- | Hampshire | J9 | Winchester (North), A34 road |- | Hampshire | J10 | Winchester (South) |- | Hampshire | J11 | Stockbridge |- | Hampshire | J12 | Eastleigh |- | Hampshire | J13 | Chandlers Ford |- | Hampshire | J14 | M27 motorway, Southampton |}

Traffic

The motorway is a critical and heavily used artery, particularly the section between Junction 4 and the interchange with the M25 motorway, which experiences significant congestion during peak hours. It serves a high volume of commuter traffic for towns like Farnborough and Basingstoke, as well as freight traffic heading to and from the port of Southampton. Annual average daily traffic flows exceed 100,000 vehicles near Basingstoke. The Highways Agency (now National Highways) manages traffic flow, with variable message signs and active traffic management systems deployed to mitigate incidents and congestion.

Future developments

Proposed future developments have historically focused on increasing capacity. A major scheme to widen the section between Junction 2 and Junction 4a to four lanes was completed in the 2010s. Ongoing studies by National Highways consider the potential for further smart motorway upgrades, including the implementation of all-lane running, though such plans are subject to review following government policy changes. Long-term strategic plans within the Department for Transport's Road Investment Strategy may also consider improvements to the junction with the A303 road to support traffic to the South West England region.

Category:Motorways in England Category:Transport in Hampshire Category:Transport in Surrey Category:Transport in Greater London