The secret to avoiding red lights during rush hour in Utah's largest city may be as simple as following a bus.
Traffic officials have spent the past few years refining a system in which radio transmitters on shuttle buses communicate directly with traffic lights around Salt Lake City, asking for a few extra seconds of green light as they approach.
Traffic congestion on these so-called smart streets is already noticeably smoother, but this is just a small taste of the high-tech upgrades that could soon be rolling out to roads across Utah and eventually the entire U.S.
Backed by a $20 million federal grant and an ambitious call to "connect the West," the goal is to ensure that every vehicle in Utah, as well as in the neighboring states of Colorado and Wyoming, can eventually communicate with each other and the roadside infrastructure about congestion, accidents, road hazards and weather conditions.
With this knowledge, drivers can immediately know when to take a different route, without having to call a human to manually send a warning to an electronic traffic sign or a map app on a mobile phone.
"A vehicle can tell us a lot about what's happening on the road," says Blaine Leonard, a transportation technology engineer with the Utah Department of Transportation. "Maybe it braked really hard, or the windshield wipers were on, or the wheels were spinning. The car is anonymously sending us that blip of data 10 times a second, giving us a constant stream of information."
When cars transmit real-time information to other cars and to various sensors along and above the road, the technology is broadly known as vehicle-to-everything, or V2X. Last month, the U.S. Department of Transportation unveiled a national blueprint for how state and local governments and private companies should implement the various V2X projects already in the works to ensure everyone is on the same page.
The overarching goal is universal: to drastically reduce the number of road deaths and serious injuries, which have recently risen to historic highs.
A 2016 analysis by the National Highway Traffic Safety Administration concluded that V2X could help. Implementing just two of the first vehicle-to-everything applications nationwide would prevent 439,000 to 615,000 crashes and save 987 to 1,366 lives, the study found.
Dan Langenkamp has been lobbying for improvements in road safety since his wife Sarah Langenkamp, a US diplomat, was killed by a truck while cycling in Maryland in 2022. Langenkamp was present at the press conference announcing the plan for a "vehicle-to-everything" and urged US governments to roll out the technology as widely and quickly as possible.
"How can we as government officials, as manufacturers, and as Americans not move this technology forward as quickly as possible, knowing that we have the power to save ourselves from this disaster, this crisis on our roads," he said.
Most of the public backlash has been about privacy. While the V2X rollout plan is committed to protecting personal information, some privacy advocates remain skeptical.
Critics say that while the system can't track specific vehicles, it can collect enough identifying characteristics (even something as seemingly innocuous as tire pressure) that it wouldn't take too much work to figure out who's behind the wheel and where they're going.
"Once you have enough unique information, you can reasonably say that the car driving down this street right now that falls into this particular weight class probably belongs to the mayor," said Cliff Braun, deputy director of technology, policy and research for the Electronic Frontier Foundation, which advocates for digital privacy.
The federal blueprint says the nation's top 75 largest metropolitan areas should aim to have at least 25% of their signalized intersections equipped with the technology by 2028, with higher milestones in subsequent years. With its quick start, the Salt Lake City area has already surpassed 20%.
Of course, upgrading the signals is the relatively easy part. The most important data comes from the cars themselves. While most new cars have connected features, they don't all work the same way.
Before embarking on the "Connect the West" plan, Utah officials tested what they call the nation's first radio-based connected vehicle technology, using only data provided by fleet vehicles like buses and snow plows. An early pilot program improved bus service on a busy stretch of Redwood Road, and it's not just bus riders who have noticed a difference.
"Whatever they're doing, it's working," said Jenny Duenas, assistant director of nearby Panda Child Care, which enrolls 80 children between the ages of 6 weeks and 12. "We haven't seen traffic in a while. We have to drop our kids off here, so when it's a lot freer, it's a lot easier to get out of the daycare."
Casey Brock, supervisor of bus communications for the Utah Transit Authority, said most of the changes may not even be noticeable to drivers. But even cutting a few seconds off a bus route can dramatically reduce congestion while improving safety, he said.
"From a commuter's standpoint, it can be, 'Oh, I had a good day on the road,'" Brock said. "They don't need to know all the mechanics that go on behind the scenes."
This summer, Michigan opened a 3-mile (4.8-kilometer) stretch of a connected, automated vehicle corridor planned for Interstate 94 between Ann Arbor and Detroit. The pilot project involves digital infrastructure, including sensors and cameras installed on poles along the highway, that help drivers prepare for traffic delays by sending alerts about things like debris and stopped vehicles.
Similar technology is being used for a smart freight corridor around Austin, Texas. The corridor is intended to inform truck drivers about road conditions and eventually meet the need for self-driving trucks.
Darran Anderson, director of strategy and innovation for the Texas Department of Transportation, said officials hope the technology will not only boost the state's massive freight industry but also help reverse a troubling trend that has lasted more than two decades. The last day without a fatality in Texas was Nov. 7, 2000.
Cavnue, a subsidiary of Alphabet's Sidewalk Infrastructure partners in Washington, D.C., funded the Michigan project and has been awarded a contract to develop the Texas project. The company has set itself the goal of becoming a leader in smart roadway technology.
Chris Armstrong, vice president of product development at Cavnue, calls V2X "a digital seatbelt for the car," but says it will only work if cars and roadside infrastructure can communicate seamlessly with each other.
"Instead of speaking 50 different languages, we all want to speak the same language," he said.