How Fibre Networks Enhance Safety on Smart Motorways

Road congestion remains a critical challenge worldwide. A 2017 INRIX study revealed that congestion alone cost the United States $305 billion (€257 billion). In the UK, Highways England estimates that congestion on motorways and major roads costs £2 billion (€2 billion) each year.

In light of these staggering figures, many governments are experimenting with “smart motorways”—high‑capacity roads that use the hard shoulder as a traffic lane and employ variable speed limits to keep traffic flowing. The first trial began in the UK in 2006, and the concept is now being explored in countries such as Australia, New Zealand and Switzerland.

Smart motorways come in several configurations, but the most common features are the use of the hard shoulder as a running lane and dynamic speed limits. These measures are designed to increase capacity—sometimes by up to 30%—and smooth traffic flow.

Areas for Improvement

While data shows that smart motorways can boost capacity, the UK’s Department for Transport (DfT) report indicates that they carried 10.7% of motorway traffic between 2015‑18 but were responsible for 11.4% of serious casualties. This suggests that, if expanded, the technology must prioritise safety above all else.

At the heart of most smart motorway systems are cameras and induction loops spaced roughly every 400 metres. These point sensors can miss incidents between intervals, leading to delays and increased risk. For instance, the DfT report notes that the camera‑based system averages 17 minutes to detect a vehicle in distress, with another 17 minutes for a rescue team to arrive—an overall response time that can be lethal on high‑speed roads.

Leveraging Fibre for Continuous Monitoring

Smart motorways already rely on fibre optics to connect cameras and loop sensors. This fibre can be repurposed as a high‑resolution Distributed Acoustic Sensor (DAS) network, effectively turning the cable into thousands of vibration detectors. These sensors capture the acoustic signature of vehicle movements—such as sudden braking, lane changes or stalled vehicles—providing real‑time incident detection across the entire motorway, not just at fixed points.

By filling the gaps between traditional cameras and loops, DAS‑enabled fibre networks deliver continuous coverage, reduce false alarms, and trigger automated alerts instantly. Faster incident identification means quicker response, fewer accidents, and smoother traffic flow.

Smart motorways are still evolving, but safety must remain the top priority. While existing sensors provide a baseline level of performance, integrating fibre‑based acoustic sensing represents a powerful next step—leveraging existing infrastructure to deliver smarter, safer roads.

The author is Chris Shannon, CEO, Fotech Solutions.