An ancient stone-arch bridge in Scotland has been given a modern upgrade thanks to intelligent transport technology from German firm Yunex Traffic.

The Category A listed stone arch bridge is 45m long, but only 5m wide and has no footways; traffic in the past gave way informally, with refuges available for pedestrians.

Yunex Traffic commissioned a Plus⁺ traffic signal and control system on the historic Nith bridge near Thornhill in Dumfries & Galloway. This provides fully signalled control for all users, enhancing safety while respecting the structure’s historic character.

To support the council’s aim of creating a safer pedestrian and cycle link across the bridge, Yunex, working with active travel engineering consultancy Transport Planning & Engineering (TP&E), designed, supplied and installed a shuttle signal system, featuring the company’s Plus⁺ traffic control and Yutraffic Actis signal head technologies.

Given the width and historic importance of the bridge, the Plus⁺ system’s distributed architecture eliminated the need to route heavy 20-core copper cable across the bridge, a requirement for traditional signalling of this type.

In designing the scheme, a number of signalling strategies were considered, including on‑crossing pedestrian detection. However, due to the bridge’s length, lack of footways and the possibility that pedestrians may pause to enjoy the views while crossing, a fixed clearance timing approach was chosen. An all-red phase provides pedestrians and cyclists with sufficient time to cross safely, without relying on detection systems.

Commissioned at end of March, the scheme incorporates Mova control and rest on red, and includes cycle detection. To improve pedestrian confidence and reduce dilemma zones on what is one of the longest crossings of its kind in the UK, the design also includes near‑side and far‑side pedestrian countdown indicators, as well as audible signals, tactile cones and angled tactile paving.

“The unique requirements of the Nith Bridge scheme were fully met by Plus⁺, thanks to its innovative architecture, and minimal cabling and civil works,” said Wilke Reints, managing director for Yunex Traffic (www.yunextraffic.com) in the UK. “This project is a perfect demonstration of the capability and versatility of Plus⁺ across a wide range of applications. We were able to deliver all the components needed for this of this clever design, which will improve safety for all bridge users.”

Rowena Colpitts, head of TP&E (tpande.scot), added: “This has been an exciting project to work on with the local community group KPT Development Trust. It has been a long-held aspiration to link the two Dumfriesshire villages and the route over the bridge has caused consternation for as long as people and traffic have been mixing on it. Now a seamless interface has been set up where pedestrians and cyclists can move easily and safely across the bridge with quick and reactive signalling for vehicles. This has greatly lowered frustration and created a good example of how existing infrastructure can be altered to accommodate all road user needs.”