Exploratory Advanced Research . . . Next Generation Transportation Solutions

of California at Berkeley, this 2-year project has 

some ambitious goals. “We are trying to see what 

connected vehicle information can do with traffic 

signal control and want to come up with new ways 

to time signals and develop new control strategies,” explains Skabardonis. “Our research makes 

it clear that adaptive control produces benefits 

over fixed-time control but implementation in realworld driving scenarios makes widespread adoption very challenging.”

Control Concepts

The study looks at three control concepts: mobility, 

environmental, and safety. The first, mobility, looks 

at strategies to avoid traffic saturation in the middle of a grid network. The aim is to use measurement samples to predict traffic, average travel 

times, and the proportion of stopped vehicles. 

From this data, schemes like “gating” can be developed, where queues are prevented from forming at the periphery of a network. The environmental concept examines fuel consumption and 

emission results, and how signal phase and timing 

(SPAT) can be used to save fuel and lower emissions. These savings could be quantified and then 

used to design optimal trajectories to enhance 

savings as a vehicle drives through a signalized 

corridor. The final concept, safety, looks at how to 

take full advantage of connected-vehicle data to 

analyze intersection geometry and detect approaching and waiting vehicles that may conflict. 

The Exploratory Advanced Research Program Fact Sheet

Changing Signals 

This study is focused on the concept of vehicle-toinfrastructure (V2X) cooperation via the Intelligent 

Transportation Systems (ITS) initiative; something 

which could provide comprehensive real-time information on the movements of vehicles throughout 

the entire road network, lead to a transformational 

change in how traffic is controlled, and address the 

significant problem of congestion along arterial 

routes. Until recently, the main impediment to improvements in traffic signal systems has been the 

limited ability of available fixed-point detectors to 

measure the true state of the traffic network and its 

response to signal changes. However, the widespread availability of traffic probe data can now provide real-time measures of effectiveness that allow 

objective signal control and measurable improvements in the efficiency of the traffic network. 

According to Alex Skabardonis of the University 

Poor traffic signal timing accounts for an estimated 10 percent of all 

traffic delay—about 300 million vehiclehours—on major roadways alone, according to a study by the Oak Ridge 

National Laboratory. A fundamental rethink of traffic signal operations, based 

on the impending widespread availability of traffic probe data, is the goal of 

“Advanced Traffic Signal Control 

Algorithms,” a project of the Federal 

Highway Administration’s (FHWA) 

Exploratory Advanced Research (EAR) 

Program in partnership with California 

Department of Transportation, University of California at Berkeley, BMW, and 

University of California at Riverside.

Investigating Advanced Traffic Signal Control 

Examining the Effect of Traffic Probe Data on Traffic Signal Operations

©www.istockphoto.com/Lya_Cattel

Traffic crossing an intersection.
In addition, intersection priority could be given to 

emergency vehicles, transit vehicles, or individual 

vehicles under low-traffic conditions, reducing delays and the need to stop.

Efficient Solutions

Project partner BMW is focusing its research on the 

vehicle itself. This part of the study looks at the development of algorithm sequences for a connected 

vehicle to inform only relevant traffic signals about 

the vehicle’s proximity, velocity, and signal request. 

Information is sent from a traffic signal to a cloudbased data center, and then communicated over a 

3G/4G network to in-car applications. With this data, 

the car is able to display SPAT information to a driver and, if required, adapt the cruise control in realtime, according to the vehicle trajectory, to get 

through a signal corridor without stopping. The 

technology, called “Smart Cruising,” also allows a 

driver to choose between reduced travel time or increased fuel efficiency. Using Motor Stops 

Automatically technology, the vehicle can drive 

while the engine is switched off, effectively “sailing” 

along a corridor. 

Moving Forward

By basing traffic signal control on a more complete 

knowledge of the state of the traffic network, this 

study could bring major improvements to the operational efficiency of arterial traffic signal systems. 

“This research will pave the way for many future 

works to be carried out by the U.S. Department of 

Transportation and its partners in an effort to develop a new generation of traffic signal control strategies,” says David Yang at FHWA. “Ultimately this 

could lead to reductions in travel time and the frequency and duration of stops, in addition to reductions in pollutant emissions and fuel consumption.” 

Before implementing a new control strategy at a 

real intersection, the research team plans to use 

real-world traffic and vehicle data to calibrate a traffic simulation, which can then be used to represent 

What Is the Exploratory 

Advanced Research Program?

FHWA’s Exploratory Advanced Research (EAR) 

Program focuses on long-term, high-risk research with a high payoff potential. The program addresses underlying gaps faced by applied highway research programs, anticipates 

emerging issues with national implications, 

and reflects broad transportation industry 

goals and objectives. 

To learn more about the EAR Program, visit 

the Exploratory Advanced Research Web site 

at www.fhwa.dot.gov/advancedresearch. The 

site features information on research solicitations, updates on ongoing research, links to 

published materials, summaries of past EAR 

Program events, and details on upcoming 

events. For additional information, contact 

David Kuehn at FHWA, 202-493-3414 (email: 

david.kuehn@fhwa.dot.gov), or Terry Halkyard 

at FHWA, 202-493-3467 (email: terry.halkyard@

fhwa.dot.gov). 

a wide range of intersection configurations and 

traffic patterns. It is expected that the simulation 

results will show how effectively probe-based 

control strategies can improve travel times, stopping frequency, fuel consumption, and emissions.

Learn More

For more information on the Advanced Traffic 

Signal Control Algorithms project, contact David 

Yang at FHWA, 202-493-3284 (email: david.yang@

dot.gov).

Publication No. 

FHWA-HRT-11-044

HRTM-04/04-11(1M)E

Investigating Advanced Traffic Signal Control 

Examining the Effect of Traffic Probe Data on Traffic Signal Operations

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©www.istockphoto.com/ 

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