SmartSensor HD’s true high definition radar is helping to manage traffic, ease congestion and reduce costs on the UK’s M25 by contributing reliable data to Smart Motorways schemes like all-lanes running.

Project Team

Connect Plus, the private consortium that manages the M25 for Highways England; and Skanska Balfour Beatty, a Connect Plus partner.

Project Scope

Implement an all-lanes running scheme on the M25 to accommodate more traffic by better using existing infrastructure instead of widening the roadway, adding more lanes or building new roads.

Problems and Challenges

The M25 is one of the most important motorways in Europe. Since its opening in 1986, the M25 has experienced rapid traffic growth that has resulted in overcrowding issues.

Managing traffic on the M25 poses two challenges. First, demand has grown faster than expected.  In 1993, the Independent newspaper reported the M25 was exceeding capacity design by around 120,000 vehicles a day.

Second, the 2009 economic downturn has led to an examination of how projects are funded.  Plans to add more lanes to the M25 were eliminated because of the failing economy; now, an attitude has developed that discourages expensive road construction projects and encourages traffic engineers to be creative with their traffic management solutions.


All-lanes running schemes eliminate the hard shoulder in order to utilize that road space without widening the roadway.  Reliable vehicle detection is key, and the project team selected SmartSensor HD in place of loops to detect capacity, monitor traffic flow, and measure queue formations.  By using SmartSensor HD to monitor traffic, the system is able to keep traffic flowing more efficiently on the M25.

“The concept of the all-lanes-running scheme is being maintained as the best value solution going forward,” says John McGinty, project director at Skanska Balfour Beatty.  “It provides the highest vehicle capacity for each pound of public money spent.”


SmartSensor HD integrates well into larger systems that may use different types of technology.  The sensor installs above the road, can be configured very quickly and is very reliable – it requires no routine maintenance, so road workers’ exposure to danger is reduced.  With reliable and accurate vehicle detection, the all-lanes-running scheme is providing improved trip times and a significant reduction in accidents, eliminating the immediate need to invest in expanding the existing road.