Innovative Traffic Signals Shorten Travel Time on US 34 Business Route in Greeley

August 2, 2012 - Northeastern Colorado/CDOT Region 4 - The Colorado Department of Transportation (CDOT) and the City of Greeley Transportation Division recently partnered to install an “Adaptive Traffic Signal” control system on US 34 Business (10th Street) between 23rd Avenue and 59th Avenue.

The purpose of this partnership was to improve signal timing and travel times along this corridor.

“By working together to incorporate these new signals into a stretch of US 34 Business that carries 30,000 vehicles a day, we were able to cut down commute times for thousands of area residents,” said Eric Bracke, Greeley traffic engineer, and Larry Haas, CDOT traffic operations engineer. “Not only will motorists notice the shorter amount of time it will take to drive through this corridor, but they will also benefit from less congestion, less wear and tear on their vehicles, and long-term fuel savings.”

The adaptive traffic signal technology is an innovation in traffic engineering that utilizes real-time data gathered by sensors to optimize signal timing for each intersection along a given corridor. This means that the signal timing is constantly changing at any given moment to accommodate the traffic patterns, creating as many green lights as possible for drivers, called a “green tunnel.” The signals are also communicating with each other so that each signal is aware of traffic flows that are approaching intersections, which means that when vehicles are approaching an intersection, they may not need to stop before their presence is detected so the light can change to green.

“In addition to the citizens of Greeley benefiting from the technology, so does the city,” said Bracke and Haas. “With smoother traffic flows, there are fewer emissions put into the air and potentially fewer accidents.”

Several cities throughout the United States have already implemented these tech-savvy systems, and Greeley is one of only two cities in Colorado to have done so; Woodland Park being the other. Traditionally, signal timing is generated by using a computer to produce a “time of day plan.” This plan attempts to progress the vehicles through each light in the corridor at a predetermined pace based on average traffic volumes and the amount of time it takes to get from one signal to the next.

Since the adaptive signals were activated in April 2012, the corridor has seen many benefits, including:

  • Travel time decreases of 9 to 11 percent through each light in the corridor
  • A 13 to 35 percent drop in stopped vehicle delays (depending on time of day or day of week)
  • A 13 percent increase in average travel speed
  • Reduction in the number of vehicle stops between 37 and 52 percent
  • A 4 percent reduction in fuel consumption

When considering the costs associated with these improvements, including time and the cost of fuel, the daily cumulative savings to motorists in Greeley is $3,789 which equates to an annual savings of $1.3 million.