Traffic Technology International | May 2021
Reliable, accurate enforcement
FlexMag sensors – featuring wireless magnetometer technology can be installed in minutes and in a matter of hours be transmitting real-time data for a variety of traffic applications
Accurate, reliable traffic detection at our 1 busiest intersections is critical for a multitude of applications, and this is especially true for red-light enforcement. Such systems require accuracy for safety and to withstand legal scrutiny. Unfortunately, the base detection technology can pose challenges for agencies trying to keep systems working consistently. Years of real world experience now show that wireless FlexMag sensors from Sensys Networks deliver the needed accuracy and improve reliability for these safety applications.
Red light enforcement systems usually employ detection before the stop bar to trigger photo capture of violations. For example, if the signal is red, and a vehicle 5-10ft (1.5-3m) from the stop bar is traveling 5mph (8km/h) or above, that vehicle is likely going to run the red light. The camera system is triggered to capture the vehicle entering and proceeding through the intersection when the signal is red.
300M The number of detections each Sensys Networks FlexMag sensor is capable of
1. Accurate sensors are essential in order to issue legally watertight red-light infraction fines
The state of detection methods
Inductive loops, simply by virtue of being the oldest detection technology, have been used worldwide for every traffic detection application imaginable. The biggest challenge with using loops is that they’re relatively fragile, requiring time-consuming maintenance and expensive replacement. Not only do they speed the deterioration of roads, due to the sawcuts and trenching during installation, they’re also more liable to break with wear and tear from vehicles and weather – particularly in locales where snow or ice conditions require salting and scraping.
Using video detection for triggering red light enforcement poses its own challenges. First, they typically require a secondary pole to be installed directly at the intersection overlooking the stop bar. This adds significant cost. Lightning also causes problems for cameras, which tend to be more susceptible to residual strikes. Most importantly, video detection suffers from occlusion and/or other visual impediments that can reduce reliability.
2. The FlexMag sensor has an incredibly small footprint compared to traditional loops
The rise of the in-road sensor
Jonathan Crabb, field services manager for Verra Mobility, has extensive experience across the United States with detection technologies. After using loops and video detection for years with mixed results, Crabb and his team decided to look at more cost-effective in-road detection solutions and settled on FlexMag.
These wireless sensors then became their primary detection solution because of the simplicity and durability they provide. In particular, the latest generation of FlexMag with improved chipsets and longer- lasting batteries have shown a marked improvement in performance and reliability.
Better tech = safer roads
Indeed, other red light enforcement technology firms confirm that FlexMag sensors tend to capture more violations and fewer false triggers due to its accuracy and reliability. Broadly, red light enforcement systems have been shown in multiple studies around the world to reduce fatalities. FlexMag has demonstrated the necessary capabilities in challenging environments across the US, improving the safety and enforceability of these systems.
