Wireless Traffic Detection
Complementing the company’s proven loop and radar detection solutions, WiMag provides vehicle and bicycle detection systems using low power wireless technology to transmit data to host controllers. The WiMag solution uses battery-powered wireless sensors installed beneath the surface of the road, sending information to the traffic controller without the need for expensive cabling or duct works.
Innovation in Cycle Highway Design and Integration
As part of the reduction in air pollution, a cycle superhighway is planned by Cardiff Council and Siemens have been engaged as a consultant to design an efficient, innovative solution to keep vehicles and cycles moving safely on the carriageway. This JCT Symposium presentation highlights one of the many innovative cycle schemes throughout Cardiff using technologies such as magnetometer detection, nearside pedestrian signals used as farside indicators, low level cycle signals, SCOOT for cycles and overhead cycle detection.
The installation, maintenance and removal of ducting and cabling in the highway is typically costly and time-consuming, leading to increased impacts on the road network. Siemens WiMag provides an alternative solution in favour of a faster, easier and more cost-effective detection system.
Each WiMag detector is placed into a small hole that has been ‘cored’ in the carriageway surface which is then fixed in place with epoxy resin.
Equipped with sophisticated wireless technology and a dedicated battery, the detectors can operate effectively for extended periods expected to be up to 10 years, with a warranty period of 5 years.
With in-built wireless transmitters/receivers, the detectors communicate with nearby Access Points or battery-powered Repeater units that are typically installed above traffic signal heads and on suitable poles. The access point serves as a wireless gateway to maintain connection with the detector and effortlessly establish overall time synchronisation. Configuration details are also managed and sent through the access point to other devices whilst receiving and processing all data gathered from the detectors.
In larger installations, the Repeater units can be used to extend the range between an installed detector and the access point up to approximately 300m. Two repeaters can operate in tandem for an even further distance (up to 600m) to facilitate a larger, more extensive, detector network.
The next generation of WiMag architecture
Providing additional flexibility, the new WiMag architecture allows for further options when using wireless vehicle detection at new or existing junctions.
The Access Point technology is moved to within the controller cabinet and is supported by a line-powered Repeater that is equipped with an external omni-directional antenna and is powered by a spare traffic signal core. By reducing the number of Access Points previously used at a site, a notable decrease in the required cabling is seen where costs and installation time are lower.
Where a typical crossroad may have 4 traditional Access Points installed, configuration and installation engineers would need to connect to each unit independently. However, with the new architecture condensing these access points into a single unit within the traffic controller, configuration for the whole signal site is simpler, easier and quicker. The new architecture compliments the existing WiMag solution and is well suited as an alternative option on larger sites.
Versatile and Reliable Detection
The WiMag vehicle detector contains a magnetometer sensor, equivalent to a typical loop detector device, that detects disturbances in the magnetic field to indicate the presence of a vehicle. Continuous self-calibration for the earth's magnetic fluctuations mean the detector is always operating reliably and accurately.
Utilising different technology, the WiMag cycle detector unit identifies bicycles based on their speed, by using a microwave radar-based system. To increase flexibility, the detector has a configurable range meaning there is no reliance on bicycles passing directly over the in-road detector.
The vehicle detector can function in VA, SCOOT and MOVA applications while the cycle detector has the ability to operate in VA, SCOOT and Stop Line control systems.
The WiMag solution has two options available for connecting detectors to traffic controllers, subject to the size of the installation and controller type:
- For larger sites using ST900, ST750ELV and ST950 controllers, a dedicated WiMag equipment rack can neatly accommodate all controller mounted parts of the system and is able to provide support for up to 60 detectors.
- Smaller sites, or other controller types (including non-Siemens controllers), can use the WiMag 4-channel loop replacement detector card which replicates a stand-alone loop detector card and supports up to 4 detectors and a single Access Point. Cards can be linked together to further increase the number of detectors and Access Points that can be supported. This solution is ideal for upgrading existing sites that already use loop detectors or smaller sites where only a limited number of detectors are required.