FOI release

M25, J27 to J22 'System Test'

Case reference FOI2025/00761

Received 22 April 2025

Published 3 July 2025

Request

I would like the following information:

  • What is the purpose of the 'System Test' that is being performed on, and communicated by the message signs between J27 and J23 of the M25, as of 22/04/2025?

  • What is the scheduled completion date of the test.

  • What are the success criteria of the test?

  • Why was the test not completed during the roadworks in the same area for the past 12 months?

  • How many speeding fines have been issued during the system test, and what is the total value of the fines?

  • How many cars pass through the system test area each day?

  • Was the cost of lost time included in the total cost of the system test?

  • What is the cost of the system test?

  • What are the success criteria of the test?

Response

  • The SVD (Stopped Vehicle Detection) technology is designed to monitor the motorway in both directions, detecting vehicles that have stopped, and is being upgraded on this section of motorway to the latest standards. The tests are in place to ensure the SVD system is performing to all necessary requirements.

  • The exact date is not known until all requirements are met. When we can remove the speed limit is determined by when the newly installed system is performing to our specification, rather than a strict timescale. This usually takes around 12 weeks. We are working hard to reduce this and will restore the national speed limit at the earliest opportunity.

  • The testing will ensure that the technology correctly monitors the carriageway and flags any vehicles stopped.

The key elements of the testing are:

  • Recording the road layout in the SVD system (a process that can only be completed once roadworks have been removed)

  • Training the radar that the SVD system is based on to reliably spot stopped vehicles and not create false alarms for reflections, signage and other factors

Toward the end of this testing period we check the system’s its real-life performance by using overnight closures to stop one of our site vehicles on the edge of the radar coverage area to make sure it’s detected, and its location is correctly reported to the National Highways Control room.

We need to complete this process to ensure that the radar system meets the National Highways performance standards for Stopped Vehicle Detection, enabling National Highways to close lanes, set signs and get help on the way as quickly as possible.

  • Upgrading stopped vehicle detection is a separate piece of work to building the new emergency areas. We've been delivering the projects side-by-side to minimise customer disruption. Where the 50mph speed limit remains in place after the other roadworks have been removed the new emergency areas are all open and available for use.

    Only limited testing of the new SVD system can take place whilst roadworks are present on the carriageway. Final SVD system tests commence when traffic management is removed from the carriageway and drivers are able to use all lanes of the motorway.

  • This information is not held by National Highways as we are not responsible for the enforcement of speeding offences. You would need to contact the relevant police force that covers this area for this information.

  • The system does not review the number of vehicles passing each day, but rather is being tested to detect any vehicles stopped on the road. Traffic volume statistics are available from the Department for Transport: https://roadtraffic.dft.gov.uk/#6/55.254/-6.053/basemap-regions-countpoints

  • No. The typical increase in journey times is summarised below.

Length (Miles)

Journey Time At Average Speed Pre-Works

Journey Time At 50MPH

Journey Time Impact

14.92

14m 41s @ 61mph

17m 54s

3m 13s

  • The M25 SVD J23-27 works (including testing period) are being delivered as part of a package contract with the M25 SVD J5-7 works; the total outturn forecast cost for this package is £15.145 million with the SVD works between J23-27 representing £8.785 million of that total outturn cost.

Documents

There are no documents for this release.

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