Motorway signs in the UK to stay on during power cuts in new trial
National Highways has begun a new trial to keep motorway signs on and illuminated during power cuts. The trial was detailed in the Department for Transport’s new transport resilience report published on Tuesday (3 November).
“Many of our motorways make use of sophisticated roadside technology to enhance safety and reduce congestion by automatically detecting hazards, setting variable speed limits, and providing real-time information to drivers,” the department said.
“These systems depend on a continuous electrical supply and even short interruptions can compromise both safety and network management.”
To strengthen resilience, the department noted National Highways is trialling the use of Uninterruptible Power Supply batteries across key sites. These systems are designed to instantly and automatically deliver continuous power to gantry-mounted signs if the mains supply fails, it said.
“As electrical providers continue to invest in and upgrade national infrastructure, the Uninterruptible Power Supply solution ensures that the technology remains reliable even during localised disruptions.
“In the event of a fault or outage, critical signs such as variable speed limits, lane closures, and red-X signals remain active, reducing the risk of collisions and helping traffic controllers manage incidents effectively. This ensures drivers continue to receive the information they need.
The department noted that the Uninterruptible Power Supply (UPS) systems also provide strategic resilience during major national incidents.
“Even in the event of widespread power issues, National Highways can continue to set and maintain tactical signs, enabling coordinated traffic management and supporting emergency response operations.
“This continuity helps keep the network moving and ensures motorists remain informed during the most challenging circumstances,” he said.
