M23 J8-10 Smart Motorway

Scheme outline

Upgrade of the M23 between junction 8 (the M25 at Merstham) and junction 10 (the A264 at Crawley) to Smart Motorway standard. This is the busiest section of the M23 and heavy volumes of traffic, with associated slow-downs and phantom traffic jams, can occur even at off-peak times. It is also the principal road link between London and the city's second largest airport.

The upgrade work will see the hard shoulder converted into a permanent fourth running lane, new emergency areas, minor alterations to junction slip roads and an upgrade to communications and CCTV systems. The upgraded motorway will operate with variable speed limits. A permanent 50mph limit will be applied to the westbound carriageway of the Gatwick Spur at junction 9.

This scheme is part of the Smart Motorways programme of works.

Under construction
Other upgrade
under motorway restrictions
Highway authority


What's happening on this scheme? You can add a progress update if you know more. Add a progress update
23 April 2018

Main construction works on this project will commence in mid-June 2018. This will follow the implementation of narrow lanes in early June.

20 August 2018

Work is under way now.

More information


With thanks to Tom Kitcher for information on this page.