M20

For detailed information about this topic, see Roads.org.uk Motorway Database

This article is about the motorway in England.
For the similarly numbered motorway in Ireland, see M20 (Republic of Ireland).

The M20 is the London to Folkestone motorway. It is the principal route to the Channel Tunnel from the rest of Britain, and hence one of the busiest. It is notorious for Operation Stack, a congestion managing scheme where goods vehicles queueing for the tunnel and cross-channel ferries are "stacked" along the mainline of the motorway.

Part of the motorway was one of the first to open in Britain, as the A20(M) Maidstone Bypass in 1961, but the motorway was never considered particularly important to complete east of Maidstone, and it was only the imminent opening of the tunnel which forced the final section between Leeds Castle and Ashford to be built, opening in 1991.

Route

The M20 shadows the route of the A20 for its entire length, and many junctions are with the road, or have access to it nearby. The motorway begins at junction 3 of the M25. The mainline is a continuation of the A20 Swanley Bypass, while traffic joins from the at-grade roundabout from the south, or from the grade-separated access coming from the Dartford Crossing. The first section of the motorway is surprisingly hilly as it crosses the Darent Valley, with a long descent from junction 2 with the A20 at the top of Wrotham Hill to junction 3 with the M26 at the bottom. Most traffic from the southern section of the M25 joins at this point.

After junction 4 with the A228, providing access to relatively new housing development around Snodland and King's Hill, the M20 begins bypassing Maidstone at junction 5. From here to the next junction, there are a combination of collector / distributor lanes to avoid congestion on the mainline by traffic simply trying to jump from one part of the town to the other. Junction 6 provides access to the M2 via the A229 up Blue Bell Hill, while junction 7 is the main route to the port of Ramsgate via the A249 up Detling Hill.

The M20 now passes through fairly uneventful flat and uneventful countryside, shadowing the route of High Speed 1 and the Eurostar which runs alongside it. Junction 8 is for Leeds Castle and Maidstone services, after which there's a long gap to Junction 9 to the west of Ashford. Junction 10 is a mile later, and is the main signposted route for the station and the A2070 to Hastings, and consequently is regularly congested, with numerous traffic lights attempting to keep everything flowing.

The M20 continues to follow the railway route towards the Channel Tunnel. The A20 is never far away and crosses over the motorway several times at Sellinge and Westenhanger. Junction 11 is for the B2068 (the Roman Stone Street, and a back route to Canterbury) and the Stop 24 Folkestone services, while shortly afterwards, J11a is the main vehicular entrance for the Channel Tunnel. Having lost off a significant amount of long-distance traffic, the M20 drops to two lanes at Junction 12 near Cheriton, and then ends at Junction 13 north of Folkestone. The A20 picks up the baton for traffic, passing underneath Roundhill Tunnel and heading towards Dover Docks.

Junctions

Swanley Interchange

Main Article: Swanley Interchange

Swanley Interchange is the northern terminus of M20, where it meets M25 and A20. It is a modified three-level roundabout with direct-access slips between M20 and M25 to the north.

Services

Maidstone services

Main Article: Maidstone services

Maidstone is a single-site MSA located at junction 8, and is operated by RoadChef.

Folkestone services

Main Article: Folkestone services

Folkestone Services are one of the newest on the British motorway network, opening in 2008. They are operated by Stop 24, under which name it is signed rather than "Folkestone".

Opening Dates

For detailed information about this section, see Roads.org.uk Motorway Database: M20 Construction Timeline

Traffic Data

From http://www.dft.gov.uk/traffic-counts/

Link	2002 AADF	2006 AADF	2010 AADF	2014 AADF
J1	34552	36389	33497	36335
J1-2	63014	58281	54390	55411
J2	51550	50467	59086	51650
J2-3	52212	46966	48551	49514
J3-4	107745	105917	99298	100714
J4-5	119586	121044	121063	125940
J5-6	124720	126450	79535	132238
J6-7	103283	105517	108551	116863
J7-8	74995	75825	70808	74442
J8-A20	24547	25571	24687	25745
J8-9	53081	58986	56739	55497
J9-10	53483	58608	36298	63530
J10-11	47796	50599	49991	50937
J11-11a	49514	53288	46690	49699
J11a-12	42384	45715	45096	45111
J12-13	43020	51635	53977	54954

Links

legislation.gov.uk

• The Mid Kent Motorway M20 (Maidstone — Chegworth Section) Scheme 1981

• The Maidstone By-Pass Special Road Scheme 1958

• The M20 Motorway (Medway Bridge Section) Scheme 1990

• The M20 Motorway (Chrismill Bridge Section) Scheme 1990

• The M20 Motorway (Coldharbour Lane to Sandling Section) Connecting Roads Scheme 1990 - This provides for the collector/distributor roads alongside the M20 around Maidstone

• The M20 Motorway (Junctions 4 to 7) (Variable Speed Limits) Regulations 2010

• The M20 Motorway (Junctions 3 to 5) (Variable Speed Limits) Regulations 2019

Roads.org.uk

• Motorway Database: M20

Roads UK

• Highways and Byways Route Guide

Motorway Services Online

• Maidstone Services
• Stop 24 (Folkestone) Services

Photo Galleries

• M20/M26 Junction - New Layout Ahead (September 2006)
• Stop 24 Folkestone - New Services Ahead (January & February 2008)
• M20 J8 Aerial Photos - October 2008

This is the layout of the M20 as it was in 1978. Notice the junction between West Kingsdown & the current J3.