- University of Wisconsin, Madison, researchers have tested UHF RFID technology to help motorists identify when children, pedestrians or bikes are in their path.
- The group is seeking collaboration with technology companies to commercialize the solution.
When bicycles, motorists and pedestrians share the road, good visibility helps prevent accidents. But in some cases, those on bicycles as well as drivers, may not expect or know a vulnerable pedestrian is in the vicinity—whether in busy city intersections, country roads or residential neighborhoods.
Over the past few years, researchers at the University of Wisconsin, Madison, have been engineering and testing a bicycle and pedestrian safety solution that leverages passive UHF RFID to alert motorists and cyclists of those at risk, ahead of or around them.
While an undergraduate, Yuchen Gu began studying RFID’s potential when tags are worn by those on bicycles or while walking. The safety program tested applications in which readers were mounted in cars or attached to fixed infrastructure, such as a traffic signal, or even the front of a home where children are playing.
Gu, now a PhD candidate in the engineering department, and his research team are now looking for commercial partners to further test and build out a solution.
Innovating Smart City Solutions
The project launched with support from postdoc researcher Marcos Martinez and advisor UW-Madison’s Daniel van der Weide. Initially, Gu was interested in a system that could detect the presence of bicycles not only to improve safety but prevent multiple stopping and starting of cyclists. Gu, a triathlon enthusiast who spends a lot of time on his bike, and van der Weide, who rides about 200 miles weekly, were both personally invested in making the sport safer for those on or around the bikes.
Not only are cyclists at risk of injury by cars, pedestrians face their own hazards when it comes to cyclists, especially if the pedestrian is a child or elderly.
While cycling is an efficient and healthy way for commuters to travel, Gu theorized that there needs to be a better way to help the multi-modal occupants of roads and paths to avoid collisions. “That’s how I first got interested in this project,” Gu said.
Gu participated in an IEEE Educational Megachallenge to solve a problem with smart city technology. Following that competition, for which the solution was a finalist, the team of researchers focused on building a system of RFID reflectors for cyclists and pedestrians that could trigger a traffic light when they came within range.
The work was recently revived after being put on hold during the pandemic. Testing has included several potential applications that could be adopted in and around a resident’s home.
Detecting Children at Play
One application is aimed at protecting children at play. Researchers set up a test that involved a child playing basketball in front of the house, wearing an RFID tag attached to his clothing. The UHF RFID tag comes with a unique ID encoded on it that transmits only when it is interrogated by a reader.
The team then mounted an RFID reader outside of the home. As the child played basketball, the reader captured the tag ID. The system can then trigger a response. One potential response is to illuminate a light that could warn motorists or cyclists, as they pass the house, that they should slow down because children are playing in the area.
However, it could be designed to trigger alerts for the parent inside the home, as the child is playing outside. For instance, the software could be programmed to treat the tag read area as a geofence. If the tag is being read, it means that a child is in the vicinity and therefore, playing where he should be. If the tag stops being read, the system could determine the child has left the yard or entered the road, and could then alert the parent.
In the long term, Gu anticipates that RFID tags could be integrated into clothing as is already the case is some flexible textile RFID tags.
RFID vs Bluetooth, Cameras
When considering technology options, Gu said that RFID offers low-cost, battery-free tags that would be necessary to make such a solution affordable and easy to use. Two alternatives, Bluetooth Low Energy-based beacons and ultra-wideband (UWB), serve as more ubiquitous technology because they are built into most smartphones, and commonly used in objects like AirTags. But they are both more costly and bulkier than passive RFID tags, he pointed out. A Bluetooth or UWB tag would require a source of power such as a battery, while UHF RFID tags are passive.
Because of the need for a battery, he added, users would have to remember to charge those objects.
As for the use of RFID, it provides an alternative to camera vision-based systems which can fail in difficult weather such as rain and snow. And Gu notes RFID “is naturally anonymous,” a way to identify a unique ID that indicates a pedestrian, without identifying the pedestrian themselves. “We’re not collecting any facial information or anything so I think that’s also a really great point of this technology.”
RFID tags can be read at distances typically around 30 to 45 feet, but in some cases that range can be extended as well.
Readers Mounted on Streets or In Cars
To make an RFID-based system viable, it would need RFID readers installed in the area or mounted in cars. If motorists or commercial vehicle operators were to adopt RFID readers, Gu said that would not be a difficult addition since modern vehicles already are highly computerized, with numerous antennas.
“The infrastructure is already there,” he said, although the system would require additional RFID modules and dedicated antenna. “You would have to do some reconfiguring for it to be actually reading tags.’”
If a driver has a reader in their car, they could receive an alert if an elderly pedestrian, child or cyclist is wearing a tag. In fact, the technology could potentially forward data to other cars in the area, who may not yet be within range, to indicate there is a potential hazard ahead.
The research team has conducted its work in its own lab, using off-the-shelf tags and readers.
Next, they hope to work with partners regarding commercial applications and pilots. That would be the next step, Gu pointed out, to transition an academic solution to a commercially viable one. “I’m in academia, I see a lot of papers and research about technology [over the years}” he said, pointing out that “publishing papers doesn’t really solve the problem,” so partnership with the RFID business community is the goal.
In that way, the team hopes it could ultimately offer a complete solution with real-world benefits.