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Hindhead Tunnel

Surrey, England

The Hindhead Tunnel opened in 2011 to relieve congestion on a key strategic road linking London to the South. In the tunnel, ClearWay’s Automatic Incident Detection (AID) reports incidents within 10 seconds, enabling efficient tunnel operation and increasing safety.

Installed 12 radar
Across 3.5km of tunnel
July 2011 tunnel opened

Hindhead twin-bore tunnel under the Devil’s Punch Bowl has removed a major source of congestion between Portsmouth and London.

The new 6km road includes a 2km stretch of tunnel. It was paramount that these tunnels remain operational 24 hours a day as the road is the major link connecting London to the south. During the planning phase, the highways agency identified that an advanced level of safety was needed in the tunnel area. A system was required to detect traffic incidents as they occurred. This was for two reasons: firstly, to ensure a timely response to assist people and vehicles stranded in the tunnel, and secondly, to avoid slow or stopped vehicle events escalating into major incidents as other road users become involved. Hindhead needed complete awareness of traffic flow and incidents in the tunnel at all times.

The solution needed to provide both high detection and low false alarm rates as this would keep the operator vigilant. The main issues that needed to be detected in the tunnel to maintain road users’ safety were stopped or slow vehicles, pedestrians in unauthorised areas, and debris. A further requirement was that detection performance should not be limited by environmental conditions and the ongoing performance of the system should not be dependent on regular, expensive routine maintenance, a feature that video analytic solutions are notorious for.


Navtech's ClearWay solution was installed as the automatic incident detection system for the Hindhead Tunnel

After a successful trial, Navtech Radar’s ClearWay solution was installed as the automatic incident detection (AID) system for the Hindhead Tunnel.

The trial demonstrated ClearWay’s ability to function effectively within a tunnel bore, as all artificially generated incidents were recorded and the system had a low false alarm rate of less than one per day.

Navtech installed 12 radar sensors between Hindhead’s two 1.8km bore tunnels. The radars had overlapping coverage for maximum resilience. If there was a power cut or radar fault, the area of detection would still be covered by the adjacent radars. An Ethernet network was installed through the length of the tunnel, and the data collected was reported.

ClearWay applications
Applications deployed
Other available applications
Automatic Incident Detection
Wrong-way Driver Detection
Stopped Vehicle Detection
Hard Should Monitoring
Pedestrian Detection
Queue Detection
Debris Detection
Wildlife Detection
Travel Time Data Collection
Vehicle Count and Classification
Emergency Services View

Safety, efficiency, and sustainability

The data collected by the radar sensors is displayed to the operators as a schematic view of the tunnel. The system automatically provides video footage of any incidents detected as it redirects the closest CCTV camera to focus on the event.

ClearWay automatically detects incidents and raises alerts to operators in as little as 10 seconds, giving them maximum time to manage the situation effectively and coordinate a response with emergency services. The system is not affected by changing weather or light in the tunnel, and it is able to see through smoke in a fire.

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