Optimising Traffic Flow at Marsh Mills
Roundabout with smartmicro Sensors

Optimising Traffic Flow at Marsh Mills Roundabout with smartmicro Sensors

Marsh Mills, the largest and busiest roundabout in Plymouth, Devon, handles an astonishing 35,000 vehicle movements daily. As a critical gateway for visitors and a vital commuter route connecting the eastern part of the city to the waterfront and city centre, its efficiency is paramount. To tackle congestion, reduce carbon emissions, and enhance traffic flow, a major upgrade was essential, transforming this junction into a smarter, more sustainable transport hub.

The Challenge

We asked Richard Bounds of Plymouth City Council about the issues faced when designing the renewal of this roundabout: “Plymouth City Council’s recent renewal of the traffic signals on Marsh Mills Roundabout included linked MOVA operation, this presented a number of challenges.
With detection necessary across 5 traffic lanes on high speed approaches, bridge decks and some approaches managed by Highways England, this project potentially required lengthy disruption, road closures to install ductwork, chambers and MOVA loops as well as future maintenance liabilities.”

The Solution

smartmicro sensors have consistently proven to be an industry leading choice for detection on MOVA applications across the UK, including numerous active sites in Plymouth. For the high-traffic Marsh Mills Roundabout, we deployed our cutting-edge UMRR-11 series of radar sensors — capable of covering up to six lanes, detecting vehicles over a 219-metre range, and delivering up to eight outputs via the Sensor Relay Option (SRO). This advanced capability made them the perfect choice for this complex junction.

“When the smartmicro radar was available we were able to produce a design that removed many of the maintenance issues associated with detection installed in the carriageway, and also the requirement for extensive ducting on the entries to the roundabout.” commented Matt Williams, MOVA specialist at JSTSM.

Key Features of the Solution:

• Non-Intrusive & Disruption-Free: Mounted above-ground, smartmicro sensors eliminate the need for invasive roadworks required by traditional inductive loops or magnetometers. This not only reduces traffic management and disruptions but
  also ensures a safer, more efficient, and environmentally friendly installation process.
• Multi-Lane Coverage: The powerful multi-lane detection of our sensors allowed a single unit to cover multiple lanes on several approaches to the roundabout. This not only streamlined the installation process but also significantly reduced costs, making our sensors the ultimate high-performance, cost-effective traffic detection solution.
• Ease of Installation: The ten sensors were installed over two nights by only two smartmicro engineers and were commissioned on site the following day. The UMRR-11’s were installed on the traffic signal poles with ease, utilising our 3m extension poles and ladders.

The Results and Benefits

The use of smartmicro sensors on the largest roundabout in Plymouth provided many advantages to the customer:

• Future Proof: The Marsh Mills Roundabout is now fully future-proof, ensuring seamless detection even during any future resurfacing — an advantage impossible with traditional induction loops. Unlike outdated technology, additional detection zones can be effortlessly integrated into the existing sensor, eliminating costly and disruptive installations while keeping the junction adaptable for years to come.
• Maximised Cost Savings: By eliminating the need for extensive ducting, slot cutting and disruptive traffic management, it is estimated that over £110,000 was saved by opting to deploy our above ground radar sensors.

“By partnering with smartmicro for the detection, JSTSM Ltd for the MOVA design and SWARCO for the installation. Plymouth City Council were able to greatly reduce the program, save significant costs in the installation and remove any risks of future detector loop re-cutting in a high speed environment.” commented Richard Bounds.

The Conclusion

smartmicro radar sensors emerged as the ultimate solution for replacing conventional loop detection at the Marsh Mills Roundabout, revolutionising traffic management on this busy gateway into Plymouth. By eliminating the challenges faced by Plymouth City Council and JSTSM Ltd during the junction redesign, our cutting-edge smartmicro UMRR-11 sensors delivered a reliable, cost-effective, and future-proof detection system.