TOPPENISH, Wash. — Washington state’s most dangerous intersection is where Larue Road and Highway 97 meet, just south of Toppenish.
Two-lane HIghway 97 is one of the busiest north-south corridors in the state, second only to Interstate 5. Semitrucks carrying apples, hay and livestock turn right onto Larue Road to bypass Toppenish on their way east to the Tri-Cities and beyond, or turn left in the opposite direction heading south.
These 18-wheeled behemoths need to slow down to make the turn, and fast-moving traffic often swerves into the oncoming lane to maintain speed. There’s no passing lane on Highway 97 — no way to separate industrial traffic from passenger cars, including tourists visiting the Columbia Gorge and Eastern Washington’s wineries. There’s no sidewalk for pedestrians. Everyone on the road shares two lanes and a hope that disasters can be avoided by quick-acting drivers. And that’s when the weather is good.
When the weather turns, the road becomes terrifying.
Thick fog shrouds the horizon. Slick ice and snow make it hard to come to a stop. Wildfire smoke can descend like a blanket.
Seven people have died since 2018 at this intersection. Many more have been injured.
Until recently, traffic safety officials could only track the crashes that were reported to police. They didn’t know with any certainty who was using this thoroughfare and what precisely was leading to so many collisions, and so many fatalities.
Now, a traffic sensor invented by the University of Washington’s Smart Transportation and Research Laboratory, or STAR Lab, keeps a 24-hour vigil over the intersection.
The Mobile Unit Sensing Traffic device, roughly the size of a toaster, is affixed to a telephone pole about 25 feet above the road. The MUST device uses cutting-edge technologies combined with machine learning to keep track of every vehicle that speeds by, every person who walks the shoulder, what the weather is doing and when crashes occur, or if there’s a near miss.
All the data this sensor collects is sent to safety officials with the Confederated Tribes and Bands of the Yakama Nation. The device can report a crash, including video of what happened. It can alert officials to changing weather and road conditions. The device can even relay a warning message about ice, fog or construction, or any other hazard, to electronic roadside signs. This real-time, 24/7, monitoring could be the difference between life and death.
“On this highway, actually, at this intersection, I lost my best friend in high school,” said HollyAnna Littlebull, a former Yakama Nation police officer and traffic safety engineer. “She got killed by an individual who failed to yield at the stop sign.”
Up the road, closer to Wapato, Littlebull’s sister was killed.
“She was waiting at a red light and she was killed by a drunk driver,” Littlebull said. “And so, I’ve just lost lots of family, lots of friends” on these roads.
“Most Eastern Washingtonians will tell you, we feel forgotten, but to have the UW come to us and say, ‘Hey, we want to work with you. We want to do this.' We were right here making the road safer. That's something that we can work on together as a team.”
Changing the tide
Littlebull, in her then-role as traffic safety coordinator for the Yakama Nation where she is an enrolled member, was instrumental in reaching out to the UW to forge a partnership that led to the deployment of the traffic sensor.
She’s worked for decades in law enforcement and traffic safety, responding to gruesome crashes and working to make the roads safer for her tribe and everyone sharing the roads.
“It’s extremely personal,” she said. “Trying to reduce these fatalities, trying to reduce crashes, trying to reduce pedestrian incidents is extremely personal because, you know, I’ve worked my whole entire life in this field.”
When she speaks about traffic safety on these roads, Littlebull is quick to point out that each data point that represents a fatal collision is much more than a dot on a map.
“Government is so used to dehumanizing the data that sometimes you just have to shake them up and say, ‘This was my sister. This was my nephew. This was my coworker. This was, you know, a cousin. This was a teacher,’” she said. “When I started delivering the message like that, it had more of a punch.”
The Yakama Nation oversees more than 1,200 miles of rural roads. Of all the land managed by Tribal governments in the state, Yakama Nation’s roads have the highest number of both traffic and pedestrian fatalities.
Collecting data in remote locations with scant resources is a challenge. Yet securing funding to build safer roads requires data. The data Littlebull had before the MUST device was outdated and didn’t accurately represent what was really happening on the roads.
Marrying civil and environmental engineering to traffic safety
About 10 years ago, Yinhai Wang, a UW civil and environmental engineering professor and director of both the STAR Lab and Pacific Northwest Transportation Consortium (PacTrans), started to explore how to improve devices that collect comprehensive traffic data. These can range from something as simple as a pneumatic tube that’s stretched across a street to more sophisticated technology that deploys video and special computers to monitor streets, roads and highways.
By marrying several different kinds of technology, Wang and researchers in his lab fine-tuned how to both process and analyze information collected from roadways then share the data with traffic safety officials. With the funding support from PacTrans and several other agencies, they began testing various prototypes and soon were building more sophisticated and smaller devices that were able to discern what kinds of vehicles were going by and at what speed, if there were pedestrians walking along the road and if surface conditions were changing.
In the STAR lab, researchers combined two important technologies, one that is able to detect a Media Access Control (MAC) address, a signal found in cell phones and vehicles, and another known as EDGE computing, which empowers a stand-alone computer to perform a number of complex functions without having to be tethered to the Internet.
The MUST device began to take shape. Plus, the device needed to withstand the elements: scorching summer heat and frigid winters, rain, ice and snow.
“The reason we’re able to deploy this is, basically, we have everything in one unit, with real-time computing, compared to other traditional devices that couldn’t survive in this environment,” said Wei Sun, a former UW postdoctoral researcher who now is CEO of AIWaysion, a UW spinoff company that is commercializing the MUST device.
Built-in sensors — video and environmental — store only the most basic and necessary information to the computer that’s housed in the device. The EDGE computer is then able to process the data and determine, using sophisticated machine learning, what needs to be passed along to traffic safety officials. The system’s over-the-air update capability, combined with advanced machine learning algorithms, provides the flexibility to adapt and collect diverse types of traffic and roadway-condition data — such as large trucks, agricultural vehicles, vulnerable road users and adverse weather conditions. The data collection is tailored specifically to meet the unique challenges of rural-road safety. Then the device uses common cellular networks to share information about changing conditions or a crash, plus routine data about traffic patterns.
“With this kind of comprehensive device, it really just gave you the safety insight and also a comprehensive data set,” Sun said. “You can tell a lot of stories.”
Compiling the data also can provide the foundation for the Yakama Nation to seek funding from the state and federal governments to fund roadway improvements like traffic signals or roundabouts, like the one built at the intersection of Highway 97 and McDonald Road. Before the construction, that intersection, just north of Toppenish, used to hold the grim distinction as the deadliest in Washington. It is now considered to be the safest intersection on the reservation.
The MUST device also can save lives in real time. It can send immediate alerts to reader boards installed roadside warning drivers to slow down due to changing conditions, pileups, or other hazards. As technology evolves, the MUST device could be deployed along rural roads and highways where illuminated beacons built into the roads could potentially change colors to indicate dangers. Onboard warning devices, including special apps or popular services like Google and Apple Car Play, built into vehicles could be triggered.
These types of warnings could prevent massive pileups, like one on Interstate-81 in Pennsylvania in 2022 involving more than 50 vehicles that left six people dead. More than two and a half minutes passed from the first crash to the last, said Wang, the UW professor and director of the STAR Lab.
Imagine, he said, if the police or traffic safety officials had information about deepening snow or the first collision.
“They will have plenty of time to do something, right?” he said. “You could either reduce the speed limit or you could close the roadway.”
A better mousetrap: National recognition
Littlebull wanted more people to know about how the MUST Device was helping her tribe. Showcasing the collaboration among the UW, AIWaysion and the Yakama Nation, the MUST device was entered into the National Recognition Program for Transportation Innovation, sponsored by the U.S. Department of Transportation Federal Highway Administration. The competition is called “Build a Better Mousetrap” and it recognizes frontline workers who “use their expertise and creativity to solve everyday problems that improve safety, reduce costs and increase efficiency.”
At the National Local & Tribal Technical Assistance Program Association Conference in Columbus, Ohio, Littlebull couldn’t believe it when she heard that the Yakama Nation won both the 2023 Innovative Project Award and Best-All-Round Award.
“Most Eastern Washingtonians will tell you, we feel forgotten, but to have the UW come to us and say, ‘Hey, we want to work with you. We want to do this’” was validating, Littlebull said. “We were right here making the road safer. That’s something that we can work on together as a team.”
Receiving attention from the federal government means the impact of the UW’s STAR Lab will extend beyond the Yakama Nation, beyond Washington state. This momentum was further bolstered by the Yakama Nation’s recent receipt of a Strengthening Mobility and Revolutionizing Transportation (SMART) Grant Stage 1 project from the U.S. Department of Transportation. This grant will enable the expansion of the current technology deployment from a single intersection to critical intersections and road segments along the entire Highway 97 corridor, spanning from Toppenish up to Union Gap, just south of Yakima.
“We feel extremely happy,” Wang said, “because we got this product pushed into practice and it’s generating a very positive impact.”
Yakima Herald-Republic and KIMA published related stories.
Originally published May 5, 2025
