Traffic signals

          Two cities that have implemented smart traffic signals are Gainesville, Fla., and Denver, Colo. Gainesville originally developed its traffic signal master plan in 1984, and in 1987, a computerized traffic signal system was installed. The system was based on command line, DOS-based and copper communications (1200-2400 baud modems). In 1997, a study was performed to determine the future needs of the county, and in 2007, an $18.2 million Transportation Management System/Transportation Regional Incentive Program grant funding for countywide traffic management system was received. It was a 50-50 match grant with $9.1 million coming from the Florida Department of Transportation and 50% from the city of Gainesville, University of Florida and Alachua County. The project was completed in 2017.

          Right now, Gainesville has more than 105 miles of underground fiber optic with gigabit bandwidth; 238 traffic signals that are 98% online; more than 41 active school zones; 14-plus active mid-block crossing; flashing yellow arrows at applicable left turns; visual monitoring at all online intersections; and video detection at more than 60 intersections.

          Shelby Taylor, communications director for the city of Gainesville, said at 98% fiber optic, “we’re in the top three of how close we are in the state.”

          Taylor added there are a “plethora of reasons” why Gainesville decided to take this step. “Traffic alleviation is one main reason/part of Vision Zero for intersection safety. Having smart traffic signals allows us to maintain traffic patterns and understand which are highly used intersections and where the risks are and where we might want to consider roadway expansion.”

          Traffic signal movement used to be monitored underground now they’re able to see what’s happening and determine how long a light needs to remain green, for example. Taylor said one thing the city wants the public to know is that “none of this is stored or recorded.” The city only watches vehicles in a productive manner not as a means to identify the vehicle.

          Taylor said the city is putting in infrastructure for 27 test intersections for connected vehicles. Right now two vehicles are equipped to communicate with the technology in place.

          When it comes to traffic management systems, there’s a pyramid of building blocks used by Hillsborough County that includes intersection detection, intersection communications, advanced traffic management system software, closed-circuit television cameras, travel time monitoring, throughput detection, advanced traffic controller, signal performance measures, signal phase and timing. Gainesville refers to this as it plans its own systems.

          “As a testament to our success, we keep progressing to the next level,” Taylor said.

          Denver, Colo., has a smart traffic management center, and it has built a situational awareness tool for it that takes different pieces of data and displays them on a single dashboard. This allows the traffic engineers to quickly identify issues and change traffic light signals to decongest the roadways.

          The following data is displayed on the dashboard: car accidents (from 911 computer-aided dispatch); road closures (from Accela, the city’s permitting tool); special events like sporting games, festivals, marches (from Office of Special Event Excel spreadsheet); traffic infrastructure like traffic cameras, fabric access points, streetlight locations (from GIS database); aerial imagery (from GIS database); power outages (from Excel); and stream gauge level data (from the Urban Drainage and Flood Control District).

          Denver considers this revolutionary because it’s in real time so the city can react immediately to a backup on the roads, and the single view reduces the number of systems traffic engineers have to log in and look at to see what’s happening on the streets, according to Heather Burke-Bellile, public information specialist for Denver Public Works.

          As an example of the tool’s use, if there is a crash at an intersection, traffic engineers can monitor it and decide if they need to change the length on the lights to keep traffic moving.

          Burke-Bellile also shared this example via email. “One morning a contractor blocked off two of the lanes on Santa Fe Drive, which is a major arterial coming into the city from the south. Looking at the dashboards, traffic engineers confirmed there were no planned road closures. This then allowed the traffic engineers to get the illegal construction lane closure out of the way, change the green light times and restore traffic patterns within 15 minutes, turning a potential three-hour backup to just 15 minutes.”

          Burke-Bellile also shared, “Denver is excited to be testing the next wave of innovative transportation technology to help improve congestion and move more people safely around the city. In Denver, we are becoming the ‘test bed’ for the rest of the country for ‘connected vehicle’ technology. This technology will one day enable traffic signals to wirelessly ‘talk’ to cars.”

          She said in the future connected vehicles will help traffic signals determine how much “green time” to give, especially during peak travel times. At some point in the future, drivers using this technology could receive notifications if they’re at risk of hitting a pedestrian or if someone is about to run a red light. One day this data will feed directly into Denver’s Traffic Management Center so the city can monitor real-time events.

          For example, if two cars crash in the middle of an intersection, the vehicles will “talk” to the TMC, notifying it so alerts can be sent to emergency response and traffic can be redirected. During snow season, if vehicles are skidding on a bridge, the vehicles would be able to “talk” to the TMC so a snowplow can be alerted and receive priority green lights at traffic signals while they are en route to respond.

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