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The dedicated short range communications project for traffic signals in Salt Lake City could be a stepping stone toward preparing roads for "talking" cars.
Anticipating a future where vehicles will communicate with one another and the infrastructure around them, Utah’s transportation department is planning to test wireless technology early next year in the Salt Lake City area to see if it can help keep transit buses running on time.
The testing will rely on what’s known as “dedicated short range communications,” commonly referred to as DSRC. Such wireless technology is poised to provide the foundation for so-called “vehicle-to-vehicle” and “vehicle-to-infrastructure” communication systems in the coming years.
Allowing for vehicles to send and receive information—or “talk”—through a variety of DSRC applications is widely viewed as a way to cut down on crashes and reduce traffic congestion.
If carried out as planned, the testing in Utah will be the first time the state has installed DSRC devices on its roadways and—most likely—among the earliest uses of the technology on a bus route anywhere in the United States, according to Blaine Leonard, the intelligent transportation systems program manager at the state’s Department of Transportation.
“We might be the first to put this in real operation for buses,” he said during a phone interview on Wednesday.
Similar DSRC systems have been tested on a limited scale at a handful of intersections in Palo Alto, California, and north of Phoenix, Arizona. And, in September, the U.S. Department of Transportation awarded New York City, Tampa, Florida, and the state of Wyoming up to $42 million to conduct pilot programs with vehicle-to-vehicle and vehicle-to-infrastructure technology.
Alternative to an 'Old Fashioned System’
The immediate goal of the Utah test program is to use DSRC technology to enable Utah Transit Authority buses to communicate with traffic signals along Redwood Road, a major state-owned, north-south thoroughfare that runs through Salt Lake City and other nearby areas.
If a bus is running late, a green light might be extended, or a red light shortened, to help the driver make up time and get back on schedule.
Leonard described the process as “an ongoing communication between the bus and the traffic signal.” He added that “the signal will make a decision as to whether it can justify giving the bus some additional priority at that intersection.”
There are currently other technologies available to achieve this type of traffic light prioritization for transit and emergency vehicles. In fact, there has been a signal priority system in place since around 2008 for buses in the Salt Lake City area on an east-west road known as 3500 South, according to Hal Johnson, project development manager at the Transit Authority.
But Johnson noted by phone on Friday: “It’s kind of an old fashioned system.”
The DSRC technology the state’s DOT is planning to put in place is more advanced.
The traffic light priority system now used on 3500 South is not uncommon in the U.S. It relies on light-emitting devices affixed to buses, which send a signal to a light receiver that is mounted near each stoplight. When triggered, the system provides buses with 10 extra seconds of green light time or 10 less seconds of red light time, Johnson said.
Installing DSRC technology at intersections opens the door for a host of information to get exchanged between traffic lights, buses and eventually other vehicles as well.
A vehicle equipped with DSRC technology is able to send out radio messages with information such as the vehicle’s type, speed, weight, location, direction and braking status, explained Leonard, who also chairs a working group on “connected” and automated vehicles for the American Association of State Highway and Transportation Officials.
“That will be broadcast continuously, ten times a second, to other vehicles around it,” Leonard said, referring to the radio messages a car could send out. “Other vehicles will be able to receive that message, and these vehicles can talk to each other.”
Allowing for this back-and-forth communication will enable automakers to build collision-avoidance systems and other technologies that use the data vehicles send and receive.
The types of devices Utah plans to put in place for the test program on Redwood Road will be able to send and receive these messages as well. So while the testing is intended to see if the technology can improve bus schedule reliability, it is also meant to be a step toward readying roads for a wave of DSRC-compatible vehicles that is expected in the next decade.
“We’ll have the infrastructure in place to start working on other applications to communicate with cars,” Leonard said. “That’s sort of an ulterior motive here.”
Deploying the technology on Redwood Road will involve installing textbook-sized radio devices at intersections, which cost about $2,000 each. DSRC communications equipment will also need to be installed on buses, which run on the transit authority’s 217 line. At this point, it has not been determined how many buses will get outfitted. Testing is currently slated to begin around February or March, according to Leonard. It will initially cover only three or four intersections but could be expanded throughout next year to include as many as 40.
Data from the bus line will be evaluated after the devices are up and running to determine if they are, in fact, cutting down on delays. If they are doing so successfully, the technology could be expanded to include other bus routes, Leonard said.
The testing project is part of a broader initiative Utah’s Department of Transportation and Transit Authority, along with a group of local governments, are preparing to undertake to study transportation needs along a roughly 20-mile segment of Redwood Road.
Funding for the DSRC project is coming from the state’s Department of Transportation budget.
The total cost to install the necessary equipment for the testing has not been nailed down. But Leonard pointed to an American Association of State Highway and Transportation Officials report, which estimated the cost of outfitting an intersection with DSRC equipment at about $20,000. “I’m anticipating that it’s going to be less than that for us,” he said.
K. Larry Head is a professor at the University of Arizona who has led efforts to develop new DSRC technology, including the software that will be used in Utah’s test program.
He said that traffic signal priority systems used in the U.S. typically rely on somewhat rudimentary algorithms, which can be decades old and do not consider connected vehicle data.
The software Head has worked to develop is designed to factor in information from multiple DSRC-equipped vehicles nearing an intersection. “There might be two emergency vehicles, or five, or maybe it’s transit vehicles and trucks,” he said. “We take the whole collection and solve an optimization problem to find a minimum delay for all of those vehicles.”
A small DSRC test network akin to the one that Utah is planning to install is now in place at 11 intersections in Anthem, Arizona, a community north of Phoenix in Maricopa County, according to Head. But there are only two first-responder vehicles in the county that are equipped to communicate with the devices. Head also highlighted a test project using similar technology for transit vehicles at about a dozen intersections in Palo Alto.
He and other researchers are hoping to expand the testing in Anthem to include additional vehicles, including school buses, and fire trucks.
‘Every Vehicle Will Start To Be Equipped’
The National Highway Traffic Safety Administration, which is part of the U.S. Department of Transportation, is in the process of developing a proposal for vehicle-to-vehicle communication equipment requirements on new light vehicles. Last year, the agency published an advance notice of proposed rulemaking and had planned to send a proposed rule to the White House Office of Management and Budget for review in 2016.
In May, Transportation Secretary Anthony Foxx announced that the Transportation Department would aim to get the proposal to the Office of Management and Budget by the end of the year.
Asked three times by email last week whether the proposal had been submitted to the Office of Management and Budget, a staff member in the National Highway Traffic Safety Administration public affairs office did not provide a direct response and instead sent links to various web pages with information about the proposed rule.
The idea of broadcasting detailed information about the movement of personal vehicles has previously raised privacy and security concerns among civil liberties groups. The Department of Transportation stressed in a recent statement about the pilot programs in New York City, Tampa and Wyoming that the information vehicles share would be anonymous.
Using its portion of the pilot project money, New York City intends to install vehicle-to-vehicle communications systems in 10,000 city-owned vehicles, including buses, and to also upgrade traffic signals.
Automakers, meanwhile, are already moving forward with plans to install vehicle-to-vehicle communications technology on new passenger cars. General Motors CEO Mary Barra, said last year that the company would equip the 2017 Cadillac CTS with the technology.
Head, at the University of Arizona, said the time is not far off when cars will be able to talk with one another and with roadside infrastructure, like the traffic signal system Utah is preparing to test.
“I think we all believe,” he said, “in the next ten years, every vehicle will start to be equipped.”
Bill Lucia is a Reporter at Government Executive's Route Fifty.
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