The Ultimate Traffic Optimization: Adaptive signal control with real-time predictive modeling

Co-authored by Shaleen Srivastava, Vice President and Regional Director (Americas), PTV Group and Jim Benson, Head of Alliances and Marketing, Intelligent Cities, Current, powered by GE

Traffic congestion is one of the more frustrating—and seemingly unavoidable—parts of urban living. Gridlock can have a huge impact on the quality of life for city dwellers, not only in terms of time spent commuting, but also regarding pollution and emissions. Unfortunately, city traffic is likely only going to get worse: According to the United Nations, 68% of the world’s population will live in urban areas by 2050, up from 55% today. That means as many as 2.5 billion people will be migrating to cities.

These booming urban populations will push the limits of existing infrastructure. Roadways and transportation networks are not equipped to handle the current demand, which only leads to more traffic and longer delays. Because of the nature of city planning, it is often impossible to expand roadways and transportation infrastructure to accommodate these growing populations. There’s no space or funding available to add roadways. The best and potentially only course of action is to implement a traffic control plan.

PTV’s Adaptive Signal Control Case Study at Delhi

PTV Group, one of the world’s leading providers of mobility software, simulated adaptive signal control in Delhi, India, to test the effects of its technologies on traffic congestion. Delhi is projected to be the most populous city in the world in 2028 and has an urgent need for traffic optimization. PTV leveraged its PTV Balance and PTV Epics solutions along 1.3 miles of Delhi’s Lodhi Road, which had six signalized intersections and three lanes of traffic traveling in each direction.

At the heart this simulation are the concepts of signal optimization and signal coordination. Signal coordination is used to create what PTV calls a “continuous green wave,” allowing vehicles to travel seamlessly along a route thanks to a stream of coordinated green lights. PTV Balance is designed to synchronize green lights in the peak direction of travel. When implemented, vehicles headed in that peak direction stop at as few intersections as possible, cutting down on their travel time, fuel consumption and emissions.

Signal optimization through PTV Epics, meanwhile, focuses on improving the traffic at a single intersection. It considers the volume of traffic approaching from different directions and alters the light cycle to minimize the total delay all vehicles experience. PTV Epics optimizes the timing of traffic signals by estimating traffic conditions 100 seconds into the future with the help of real-time data. It can then lengthen or shorten green lights or eliminate cycles altogether to improve the overall flow of traffic. Balance and Epics can work together in a combined system to create a traffic control plan that spans the entire network.

The Far-Reaching Benefits of Traffic Control Plans

Without Balance and Epics, PTV found that traffic along Lodhi Road during peak hours had an average speed of 11.5 mph and an average delay of 269 seconds. But with Balance and Epics running in the simulation, weighted travel times decreased by 26% while the speed of vehicles in the network increased by 27%. Additionally, the queue length at three of the six intersections was cut in half and delays along the network were reduced by 30%. Should adaptive signal controls be implemented across Delhi, the estimated economic impact would reach $33 million USD. The environmental effects of smarter traffic control is also notable. In Delhi, the better flow of traffic that would result from adaptive signal control was estimated to reduce pollution levels by between 10% and 15%. Vehicles experience reduced fuel consumption and emissions thanks to fewer stops and shorter idle times at traffic lights.

Achieving the Ultimate Traffic Optimization with Current’s Partnership

The initial proof of concept was a success, but there’s always room for bigger and better benefits. That’s where Current, powered by GE, comes in. The partnership between PTV Group and Current by GE can further enhance smart city technology. Current’s CityIQ? nodes can collect sensor data related to parking and transportation, including both vehicle and pedestrian traffic. Tools such as PTV Optima, which offers model-based real-time predictive traffic and incidence management, can take that data and translate it into actionable insights for customized traffic management solutions.

Today, most of cities are using adaptive signal control based on the vehicle queue at the intersection without the intelligence of the traffic flow in the context of the entire urban area. This approach is a reactive solution that delivers limited improvements to the overall traffic flow. By integrating the real-time CityIQ traffic data, PTV Optima offers precise, real-time and predictive traffic modeling for the entire network and produces reliable forecasts for up to next 60 minutes in 5- to 15-minute intervals. Traffic engineers can make informed decisions by simulating various scenarios with the real-time traffic data. Within a couple of minutes, a precise action can be taken based on the simulation results. Furthermore, the full integration of PTV Balance and the real-time traffic predictive intelligence from Optima enables the traffic signal control to achieve the ultimate optimization in the context of the entire urban area.

In addition to better traffic control, the partnership between Current by GE and PTV could improve public transportation options. PTV's systems with real-time CityIQ? traffic and pedestrian data can recognize and even prioritize public vehicles such as buses. This could help speed up public transport routes and make them more appealing options for citizens.

Current by GE’s smart city technology also has the power to drive economic growth. The open digital infrastructure resulting from the massive amount of data collected welcomes innovation. Individuals and corporations will be able to discover new outcomes and create new opportunities for investors and jobs.

Less traffic congestion, reduced emissions and more economic development are sure to make cities better places to live. That will be much needed in the future when such a large percentage of the population resides in urban areas.

Taking the Next Steps

Learn how Current by GE is using lighting to help build intelligent cities. With a digital infrastructure enabled by CityIQ?, traditional lighting is transformed into a data intelligence network that can positively affect all aspects of city life.

You can also explore the endless possibilities of smart city technology with the Digital Infrastructure powered by CityIQ? with Current by GE’s Innovation Apps Center. Most of the apps were designed and developed from hackathons ranged from 24 hours to several months and address a wide variety of city needs.