Local Authority Deploys Smartmicro Technology to Optimise Traffic Flow at Plymouth’s Marsh Mills Roundabout

Plymouth City Council has embraced smart traffic technology to transform one of the South West’s busiest junctions, delivering smoother traffic flow, reduced disruption, and long-term cost savings.

Handling more than 35,000 vehicles each day, Marsh Mills is Plymouth’s largest roundabout and a critical junction linking the city’s eastern corridors to the waterfront and city centre. Its strategic importance made it the ideal site for a major upgrade aimed at reducing congestion, lowering carbon emissions, and future-proofing the network with minimal disruption.

Local Authority Innovation: Rising to the Challenge

The council’s traffic signal renewal at Marsh Mills involved a linked MOVA operation across multiple approaches, including sections managed by National Highways. With high-speed traffic, five-lane approaches, and complex bridge deck layouts, the use of traditional in-road detection would have meant extensive civil works, lengthy road closures, and long-term maintenance liabilities, all of which posed significant challenges in terms of cost, safety, and disruption.

Recognising these challenges, Plymouth City Council turned to above-ground radar detection to provide a non-invasive, flexible, and future-proof solution.

Smartmicro Sensors: High-Tech Detection Without the Disruption

To meet the technical demands of the site, smartmicro UMRR-11 radar sensors were selected. These advanced sensors are capable of detecting vehicles across six lanes, with a range of up to 219 metres. Each sensor can deliver up to eight outputs using the Sensor Relay Option (SRO), making them highly adaptable for complex junction layouts.

With no need for in-road installations, the project avoided costly ducting and slot-cutting works. Instead, sensors were mounted above ground on traffic signal poles using 3-metre extension arms and ladders. The full installation of ten units was completed over just two nights by a two-person engineering team, followed by on-site commissioning the next day.

Key Advantages for Local Authorities

• Above-Ground Installation: smartmicro sensors eliminate the need for disruptive and time-consuming civil works, improving safety and reducing installation timelines.
• Cost-Effective Efficiency: The use of pole-mounted sensors and minimal traffic management significantly reduced both installation time and costs. The overall savings on the project were estimated to exceed £110,000 compared to conventional detection methods.
• Future-Proof Technology: As these sensors are not embedded in the carriageway, they are unaffected by future resurfacing. Additional detection zones can be easily integrated, providing a scalable and adaptable solution for evolving traffic demands.

Delivering Tangible Results

Through the deployment of smartmicro radar detection, along with the MOVA signal design by JSTSM and installation by SWARCO, Plymouth City Council achieved a reduction in project duration, substantial cost savings, and a safer working environment, all while enhancing traffic flow at one of the city’s most critical transport hubs.

This outcome reflects a growing trend among local authorities embracing intelligent transport technologies to modernise road infrastructure, reduce emissions, and deliver improved journey times for all road users.

Leading the Way in Smart Traffic Management

The Marsh Mills Roundabout project serves as a model of how modern radar-based detection systems can outperform legacy loop-based solutions. By integrating smartmicro’s advanced sensor technology, Plymouth City Council has significantly improved operational performance while minimising environmental and financial impact.

As towns and cities across the UK face mounting pressures to reduce congestion and operate more sustainably, initiatives like this demonstrate how local authorities can lead the way in smart traffic management and future-ready infrastructure planning.