M23 smart motorway

Highways England are upgrading the M23 between Junction 8 (M25) and Junction 10 (Crawley) to an all lane running (ALR) smart motorway. Construction starts in June 2018 and will run to spring 2020.

When it’s finished, the M23 will have four running lanes in each direction with a variable speed limit controlled by dynamic signage. The westbound spur road (towards Gatwick) will also be upgraded to three running lanes.

How will this impact journey times?

Journey times will be longer than normal. Although the usual three lanes will be maintained throughout the two-year project, a reduced speed limit of 50mph will be in place due to narrow lanes.

Why is the M23 being upgraded?

The M23 is a very busy road used by traffic travelling to and from the airport and between Brighton and London, particularly during holiday periods. As a result, safety, congestion and journey times need to be improved, which can be facilitated by a smart motorway.

Read more about the project on the Highways England website.