Hurried cyclists, impatient drivers and pedestrians who don’t look both ways before crossing the street—these are some of the obstacles Gainesville’s two autonomous shuttles must avoid while following their designated routes along Southwest Second Avenue and 13th Street.
Now, thanks to a radio traffic technology installed by Gainesville’s Regional Transit System along the shuttle’s route, the autonomous vehicle is relieved of one former liability: identifying when the light changes on the road’s traffic lights.
According to the city’s traffic operations manager, Emmanuel Posadas, the shuttle originally relied on “computer vision,” a technology that relies on visual inputs, to make traffic choices such as deciding to stop.
Now, the shuttle receives a signal from the light, as well.
Posadas explained this transmission works through roadside units, or RSUs, installed atop the traffic lights. These devices broadcast a dedicated short-range radio to an onboard unit, a device that receives this signal on the shuttle. This technology works at all 27 intersections near the University of Florida campus.
“[It] broadcasts the traffic signal status all the time, to anybody that can listen,” Posadas said.
While the vehicle still relies on visual and sensory inputs from cameras installed on board the shuttle, for other functions, this radio capability represents an upgrade from computer vision alone because it’s harder to interrupt. If a truck blocks the shuttle’s line of sight, for example, it will still know the light’s current signal color.
This reliance on different types of external stimuli—that is, sensory, visual or radio—is known as data fusion.
“You can’t just rely on vision alone, you can’t just rely on [sensors] alone, or you can’t rely on signal…alone,” Posadas said. “You kinda have to fuse all of it to figure it out.”
The installation of the RSUs around UF was part of a larger initiative by the Florida Department of Transportation dubbed Florida’s Connected and Automated Vehicle Initiative. According to the FDOT website, the project intends to encourage the exchange of communication between “vehicles, the roadside, bicyclists and pedestrians.”
Gainesville’s implementation of the statewide initiative—called the trapezium project due to the shape that the RSU’s form—became operational in 2019. However, it was not until recently that the units started working in tandem with the shuttles to enhance their autonomy.
This latest enhancement to the city’s autonomous shuttle comes only a few months after the shuttle’s route was extended to include a portion of 13th Street.
Dr. Pruthvi Manjunatha is the manager of UF’s I-STREET living lab, the university’s research-oriented stakeholder in this project. He said the initiative is slowly being rolled out–in phases. Phase 1 started in downtown, extending into the Innovation Square area. Phase 2 involves additional stops across the street from UF and the communication with traffic signals aspect.
The expansion of the route onto a busy street signifies a bold step forward for these projects, which were put on hold by the federal government in 2020 after an incident in Ohio where a woman fell inside the vehicle due to an abrupt stop for unknown reasons.
In response to the incident, new safety measures were implemented within the vehicle, including the addition of a non-slip pad and seatbelts. Federal guidelines also require someone always to supervise safety from within the shuttle.
Michelle Richter is one of two safety operators. Her job is to ensure that riders wear seatbelts, keep masks on and sometimes “validate” the shuttle’s movements on a device she carries along with her.
“That’s why we have you in a seat belt,” Richter said. “This can stop in a dime. It’s scary when it does it because you don’t expect it.”
While Richter acknowledges the shuttle sometimes moves abruptly, she tends to agree with the vehicle’s decisions, as there are countless moving parts on the road. She explained any movement the shuttle makes is to avoid hitting any person or object.
“The safety sensors that we have are perfect for here because you will see crazy kids with their phones walking in front of you,” Richter said. “I am always so thankful that this vehicle will not hit them. It will not.”
Pruthvi said he does not expect autonomous shuttles to replace buses anytime soon, saying such a statement would be speculation. This project aims to address gaps in the transportation system, not to replace the fleet.
“They call it the last mile between your community and the bus station,” Richter said. “We are looking to fill that gap.”