Solar-powered sensors have been designed to replace tube and loop counters which until now have been the usual way of counting traffic. They take just seconds to install for temporary traffic counting, and only minutes for permanent counting – meaning significant health and safety benefits.
Technical instrumentation principal Mike Lusby says for temporary traffic counts, it’s as simple as peeling off the sensor’s adhesive backing and sticking it on the road surface. For permanent deployment, sensors are bolted down.
“Compare this to traditional tube counters for traffic, which are costly and labour-intensive to deploy, have a high number of failures, lack remote data capability and have difficulty monitoring traffic across multiple lanes.”
Mike says the technology that makes the new sensor system work is commercially sensitive, but its “secret sauce” is a New Zealand-first for traffic sensing and, to WSP’s knowledge, a world-first.
The sensor registers vehicle type (e.g., cars, trucks, motorcycles) based on their size. It registers total vehicle counts, and speed and distance between vehicles – all in real-time. It also picks up direction and speed of travel. Individual vehicle details aren’t identified.
The sensor system can be used for traffic counting, road works compliance, structural loading monitoring (e.g., for bridges), speed surveys and many more applications. Data is communicated wirelessly back to WSP’s systems and presented to clients on web dashboards. It works equally well in urban, rural, and remote places.
"In developing this sensor system we've leveraged our decades of experience in transport asset management. By capturing more and better data, including that previously thought impractical to measure, it opens new possibilities for understanding road transport dynamics,” says Mike.
Richer insights captured by the sensor system ultimately mean better-informed decision-making for local or central government authorities involved in transport infrastructure planning. Plus, the small, unintrusive, standalone sensor units can be more safely installed compared with other methods - all while minimising traffic disruption.
WSP has ownership of the sensor units and take responsibility for their maintenance. Clients pay for a service and own the data generated during the service.
Mike says the small rectangular sensor units have been through the testing wringer over the past few years. Made of military-grade plastic, they’ve been driven over by 50+ ton trucks, and submerged underwater for extended periods of time. They’re motorcycle and pedestrian safe.
“We’ve subjected the sensors to endless tyre revolutions in our circular accelerator testing facility and have even buried them under the surface of gravel roads. They don’t miss a beat!”
Road trials have been held on heavily trafficked sections of road in Petone and Upper Hutt. The sensor’s count accuracy exceeds 98 percent compared with manual counts from video cameras. It has superior accuracy against other traffic sensing methods, including tube and loop counters.
WSP Research is working with various existing clients across the country to allow exclusive early access to the system before the sensors go into commercial production later in 2024.
