Utah Network of Cameras and Sensors Keeps Traffic Moving
Utah tracks traffic and weather via thousands of sensors and cameras in its intelligent transportation system.
Lisa Miller doesn’t know what her department would do without the cameras and sensors that monitor traffic conditions. Working as the traveler information manager for the Utah Department of Transportation (UDOT), Miller’s feelings were confirmed two years ago when rough weather jeopardized part of the network.
In winter 2011, winds exceeding 100 mph bombarded overhead traffic cameras in northern Utah, which was bad news for traffic monitoring.
“It knocked out our camera coverage in the area where we needed it the most, and we’ve really come to rely on the network as our eyes and ears on the road,” she said. “When we don’t have it, it’s hard to be effective and to give the traveling public the information they need.”
More than 700 cameras and 1,500 in-road sensors record photos, videos and traffic data on state roads. UDOT, local news groups and national organizations use this information to communicate traffic information to the public. There are also several weather sensors, about 80 in Miller’s estimation, that deliver weather information to drivers in the same fashion.
The public can visit the Utah Department of Transportation’s traffic conditions home page to see the data, and a map with icons depicting the locations where traffic cameras and weather sensors are currently mounted. Users can view photos of current road conditions and data on weather conditions. This information also is available on a smartphone app for Android and iPhone systems. UDOT reaches the public through social media as well, and the cameras, sensors and website information help employees keep citizens informed.
“We are very proactive at UDOT,” Miller said. “Over the past couple of years, the traveling public has really turned to UDOT as a source, a provider [and] a partner.”
Utah has full-time, in-house weather forecasters at stations dispersed throughout the state, and programs where drivers can call in to report road condition information.
A Closer Look
Most traffic cameras and sensors are located in the Salt Lake area where about 80 percent of the state’s residents live. The two types of equipment work together to gather data for the state’s traffic operations center, and then that information is disseminated to the public.
UDOT’s radar and loop sensors at intersections feed data to the department’s signal engineers in almost real time. Pole-mounted radar sensors shoot microwave beams across lanes, and vehicles that are hit by the beams reflect microwave energy back to the antenna, which is how a computer analyzes changes in speed. The department also has vehicle inductive-loop traffic detectors beneath the pavement that detect vehicles passing over them.
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Camera feeds, along with sensor data, help Utah’s employees make informed assessments about road activity. They use their knowledge to notify the public in multiple ways, including variable message signs.
“They watch congestion develop or dissipate and put messages back out to the public on overhead message signs warning of where congestion might be,” said Blaine Leonard, Utah’s intelligent transportation system program manager. “They can use that after a major ball game or a big Fourth of July celebration to sense what’s happening.”
The same statewide fiber-optic network that supports data transmission from cameras and sensors to the traffic operations center also supports data transfer from roadway weather information system sensors.
UDOT’s weather sensor network comprises various types of units. Traditional setups involve atmospheric sensors mounted on a structure near the road that communicate with ground-level sensors called “pucks” embedded in nearby pavement that read the temperature on the road.
There also are sensors mounted on poles near the road that fire infrared energy on a surface, allowing personnel to gauge how much light ice and snow reflect back from the ground. This latter group of sensors is called non-invasive because they don’t require installation on actual pavement in the middle of traffic flow.
Data gleaned from these sources allow UDOT to post up-to-date weather condition information on variable message signs statewide as well as through social media and government websites.
Foundation for Future Development
A combination of factors prompted Utah to begin deploying cameras and sensors at the dawn of the 21st century. It was a natural result of the evolution of traffic systems that had been under way throughout the 1990s.
According to Miller, the intelligent transportation system wave was rushing through the country at that time, and it influenced how cities developed their infrastructure, including Salt Lake City.
“The whole concept of intelligent transportation systems started to come alive at that time, and when you manage traffic more efficiently, it’s less expensive, it saves people time and gas,” she said.
Utah began installing cameras in the late 1990s, as Leonard recalls, and there were only a half dozen or so at first. The state was building a new intelligent transportation system in conjunction with reconstruction of Interstate 15 in Salt Lake County at the time, but that wasn’t the only impetus for increased use of traffic management technology. Soon after, Utah was selected to host the 2002 Winter Olympics, and government leaders knew an influx of tourists was coming.
“That was sort of our start, and we’ve been adding cameras in our system continuously ever since then and replacing cameras as they wore out,” Leonard said.
Neither Leonard nor Miller could name a specific cost of the overall installation or management of their decades-old system because it’s been around so long and its growth has been tied to other state projects. The freeway reconstruction was billed at more than $1 billion in the beginning.
However, Leonard spoke generally about the cost of specific cameras and sensors. A typical camera costs about $4,000, but it requires a pole and pole foundation to be built with it, as well as a cabinet with equipment inside that lets people operate the camera, which increases the total cost to about $20,000.
Sensor costs vary because there are several kinds, many with different installation requirements.
It’s safe to say that Utah’s sensors and cameras will be integral to traffic operations for the foreseeable future, and the government plans to deploy more, especially in rural areas.
“You have plenty of weather information for urban areas, but you have very little when it comes to the rural areas,” said Jeff Williams, UDOT meteorologist and weather operations program manager. “Sometimes there’s a hundred miles between towns. A lot of times, these are trucking routes where you have to make sure that commerce is not impacted.”
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