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Public Roads - November/December 2011

November/December 2011
Issue No:
Vol. 75 No. 3
Publication Number:
Table of Contents

Transporation Operations Laboratory: Article II - A Living Outdoor Laboratory

by Benjamin B. McKeever, Deborah Curtis, and Kari Beasley

FHWA's new Cooperative Vehicle-Highway testbed will serve as a proving ground for wireless technologies that connect vehicles with infrastructure.

The TFHRC intelligent intersection, shown here, was the predecessor of the Cooperative Vehicle-Highway testbed and remains its key facility.

The growing demand for research on transportation operations is due, in large part, to the increasing congestion on U.S. roads and the need for improved highway services to support the growth of the Nation's economy. One aspect of this research is investigating the use of electronics, information processing, and communications technologies to improve the safety and efficiency of the existing surface transportation system.

To support this type of research, the Federal Highway Administration's (FHWA) Office of Operations Research and Development (R&D) recognized the need to enhance its onsite capabilities. This recognition led to development of the concept of a Transportation Operations Laboratory (TOL), commitment of resources, and awarding of a contract in early 2011 to design and build the laboratory and develop a companion research plan.

Located at the Turner-Fairbank Highway Research Center (TFHRC), the TOL consists of three components: (1) a Concepts and Analysis testbed (see "Modeling Transportation Systems: Past, Present, and Future," in the September/October 2011 issue of PUBLIC ROADS); (2) a Cooperative Vehicle-Highway testbed (CVHT); and (3) a Data Resources testbed (to be discussed in an upcoming article in this three-part series). The Concepts and Analysis testbed and the Data Resources facility will be housed inside TFHRC, while the CVHT will primarily be housed outdoors on surrounding TFHRC property.

The laboratory's three testbeds are intended to provide FHWA researchers, other onsite researchers, and external customers with reliable, comprehensive, and accessible resources to facilitate high-quality research in a robust and cost-effective manner. The testbeds will operate as an integrated whole so that research performed at each facility can take advantage of the synergistic capabilities of the entire TOL. For instance, the best concepts from the Concepts and Analysis testbed could be evaluated in the field at the CVHT, and data produced and managed by the CVHT could be archived in the Data Resources testbed for additional research.

FHWA launched the TOL's initial operating capability (including all three testbeds) on September 29, 2011. "Our new state-of-the-art research facility, combined with methods that integrate all three of our testbeds, has the potential to make the TOL a unique venue for exploring innovative cooperative vehicle-highway concepts and hosting demonstrations of those concepts," says Joseph I. Peters, director of the FHWA Office of Operations R&D.

Vision for the CVHT

The Cooperative Vehicle-Highway testbed will serve as an outdoor proving ground for the testing and demonstration of advanced technologies and applications, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) wireless communications that support a variety of safety, mobility, and environmental applications. One such application, for example, involves transmitting signal phase and timing (SPaT) data through V2I communications to provide invehicle warnings to drivers who are in danger of running red lights. This application and similar U.S. Department of Transportation (USDOT) efforts will benefit from the ability to conduct onsite testing at the CVHT outdoor laboratory.

"The need to conduct validations to support cooperative vehicle-highway projects, which have the potential to fundamentally change the way transportation systems are managed, is expected to grow," says Peters. "Meeting the need to conduct comprehensive research will require a facility that is equipped to conduct forward-thinking, cooperative vehicle-highway studies."


The concept for an FHWA outdoor transportation operations laboratory began in 2003 with the installation of an intelligent intersection at TFHRC. Built through cooperation between FHWA and the Virginia Department of Transportation (VDOT), the intersection originally was used to test early Vehicle Infrastructure Integration (VII) concepts. Researchers field-tested a number of prototype VII applications at the intersection.

One application, for example, was a signal-violation warning system that alerted drivers when they were in danger of running a red light. The drivers were warned using special visual cues, such as a light-emitting diode (LED) sign with strobe flashers installed on the signal mast arm. Researchers also field-tested an LED sign that provides a visual warning to drivers indicating when it was unsafe to make a left turn due to oncoming traffic. The intelligent intersection has evolved into what is now the main facility of the CVHT.

The TOL Concept


Key Current Research at the CVHT

TFHRC already has begun using existing onsite capabilities to support the development of cooperative vehicle-highway systems. Most of the ongoing research is assisting the Intelligent Transportation Systems (ITS) Joint Program Office's connected vehicle program, which has a relatively short-term focus. In the future, the CVHT will test more far-reaching concepts.

One of the current projects involves developing a SPaT prototype, which will define a common interface between mobile devices and traffic signal controllers. By using technologies defined in current standards (SAE J2735 for the mobile devices and NTCIP 1202 for traffic signal controllers), the interface will be open and nonproprietary. This feature will facilitate revisions to the interface whenever standards change and evolve. Being nonproprietary, the interface also will enable any brand of traffic signal controller to broadcast critical information about the state of the phase or movement (red, amber, or green). Also, the interface will show the time remaining in that signal phase or movement, if that value is known.

Applications will be able to use this information to warn drivers who may be about to violate red lights or to regulate the speed of vehicles to maximize fuel efficiency. The interface is a two-way link that also will enable the signal controller to receive "requests for service" such as signal preemption from transit vehicles or priority calls by emergency vehicles. Researchers at the CVHT will test the first two prototype controllers to use this new interface in late 2011 and early 2012.

Ground-truth testing of positioning systems on Here-I-Am safety message broadcasting devices and other aftermarket equipment is another key foundational CVHT research activity. In January 2011, CVHT researchers conducted tests using onboard equipment on the CVHT's test vehicle. The research involved roadway grids that had been surveyed using high-accuracy survey methods and a high-speed video camera capable of capturing 5,000 frames per second and linked to a global positioning system (GPS) time reference.

Using the CVHT vehicle's onboard equipment that referenced the same GPS time, the researchers were able to quantify exactly where the vehicle was located at an exact point in time. They also were able to capture where the vehicle believed it was at that point. By comparing two locations at a common point in time for multiple iterations and at varying speeds, the researchers could quantify any error associated with the vehicle's positioning device. By knowing this value, they were able to account for each device's systematic error observed in the positioning data.

They repeated the same test methodology for the Here-I-Am devices that are being developed for use in the Connected Vehicle Safety Pilot program, a major research initiative that will test how ordinary drivers in real-world driving conditions will respond to wireless safety messages. The safety pilot started in August 2011 and is scheduled to run through the first half of 2013.

A key aspect of the safety pilot is to establish a deployment test site for a real-world model for enabling wireless communications among vehicles and with roadside equipment for use in generating data for driver safety warning systems. USDOT issued a request for proposals (RFP) in March 2011 to seek a set of partners from both the public and private sectors as a test conductor for the model deployment site. The award was announced in August 2011. To support the model deployment, USDOT is purchasing roadside equipment and has selected four vendors through a competitive procurement. The FHWA researchers will install the equipment at the CVHT for trial-run experiments.

The units that pass initial testing requirements based on the vendors' self-certification and basic functionality tests at the CVHT will be field-deployed at the model deployment site. After that, FHWA will place the passing units on a qualified provider's list, and they will be eligible for purchase by the safety pilot's test conductor.

Here, researchers are ground-truth testing a global positioning system in the CVHT's test vehicle. The surveyed roadway grid shown here was used as a ground-truth point of reference for assessing the positioning accuracy of various devices installed in the vehicle.

Recent CVHT Demonstration

On December 7, 2010, Secretary Ray LaHood and FHWA Administrator Victor Mendez participated in two showcase events at TFHRC: a tour of the center's laboratories and a town hall meeting with all TFHRC employees and invited onsite contractors. During the CVHT segment of the tour, LaHood and Mendez tried out the intelligent vehicle as it communicated wirelessly in real time with the intelligent intersection and a network operating center in Oak Ridge, TN. The center, which communicates to the intersection over the Internet, enables managers to send messages to the intelligent vehicle and receive them from it.

With invehicle messages broadcast from Oak Ridge through the CVHT intelligent intersection, the intelligent vehicle was able to demonstrate capabilities that could be deployed in the not-so-distant future. For example, "Use Caution, Icy Roads Ahead" appeared on the vehicle's computer screen along with an audible beep, demonstrating an advisory function while approaching an operational road weather information system. "Stop! Red Light Ahead" and an audible beep were the warnings presented as, hypothetically, the driver approached the intelligent intersection's red signal at a dangerous speed. These samples illustrate the types of messages that could be communicated to vehicles and drivers based on their specific positions, situations, or vehicle types.

At the end of the demonstration trip, the researchers showed LaHood and Mendez a map display of geo-referenced waypoints left by the vehicle and the vast array of data yielded by clicking on any one of the waypoints. These data are examples of those that might be available to a future traffic management center or a research laboratory.

Building on the success of this demonstration, the CVHT researchers have continued to provide similar tours to a variety of groups. The researchers are looking forward to sharing the experience with others and making the laboratory available for cooperative research with partners in government, industry, and academia.

An advisory message, "Stop! Red Light Ahead," appears on a display on the dashboard in the CVHT's intelligent vehicle as it approaches the intelligent intersection. The message is an example of a real-time safety alert that could be provided to motorists.

Looking Forward

One of the advantages to being a living outdoor laboratory is that the CVHT has ample opportunities to expand. To support ongoing and planned research, the CVHT researchers hope to add additional intersections equipped with roadside equipment and other enabling technology to expand the range of concepts and applications they can test. These intersections may be on existing TFHRC property or, through a potential partnership with VDOT, on actual roads in Virginia.

Other planned expansions include additional test vehicles equipped with the current onboard equipment and enhanced control features. The enhanced features could support advanced mobility applications, such as cooperative adaptive cruise control and speed harmonization.

In summary, enhancements to the CVHT may include the following:

  • Additional locations outfitted with roadside equipment that provides V2I communications, including roadside equipment integrated with a traffic signal controller to transmit SPaT data.
  • Additional vehicles equipped with onboard equipment that supports dedicated short-range communications with the roadside equipment and provides the invehicle infrastructure needed to support cooperative vehicle-highway applications.
  • Network links to USDOT's other V2I technology testbed through the network operating center in Oak Ridge. There is an existing link and testbed in Michigan, and in the future there may be links to testbeds in California, Florida, and New York.
  • Support equipment, such as high-speed cameras, vehicle sensors, and devices that can monitor and record transmissions of dedicated short-range communications.

These CVHT enhancements will position FHWA to perform cutting-edge research in support of numerous USDOT programs, including FHWA's Exploratory Advanced Research (EAR) Program, Dynamic Mobility Applications, V2I Communications for Safety, and Applications for the Environment: Real-Time Information Synthesis (AERIS). In addition, the enhancements will enable the CVHT to perform research on broader transportation operations research topics, such as adaptive traffic signal control systems.

"We look forward to developing and refining new transportation operations concepts at TFHRC and then testing and evaluating them with the help of the CVHT," says Peters. "In addition, where safe and appropriate, we can partner with State and local governments to investigate the roadworthiness of these new concepts. FHWA is committed to being a key contributor to cooperative vehicle-highway research and will lead the development and testing of related technologies and applications with the help of the new CVHT."

After a tour of the CVHT in December 2010, Secretary Ray LaHood (center, in red scarf) and Administrator Victor Mendez (on LaHood's right) are pictured with partners in the connected vehicle program: representatives from FHWA, Research and Innovative Technology Administration's (RITA) ITS Joint Program Office, and VDOT.


Benjamin B. McKeever, P.E., is the team leader of the Transportation Operations Applications Team in FHWA's Office of Operations R&D. Currently, he is leading development of the CVHT at TFHRC and supporting USDOT's Dynamic Mobility Applications and V2I Communications for Safety programs. McKeever holds an M.S. in civil engineering from The University of Texas and a B.S. in applied mathematics from the University of Virginia.

Deborah Curtis is a highway research engineer on the Transportation Operations Applications Team in FHWA's Office of Operations R&D. She has been working at TFHRC for 18 years and specializes in traffic signal systems and the connected vehicle research program. She has a B.S. in civil engineering from West Virginia University.

Kari Beasley is an industrial engineer at Science Applications International Corporation (SAIC), currently supporting the build-out and initial operations of the TOL. Beasley holds a B.S. in industrial and systems engineering from Virginia Tech.

The authors would like to acknowledge the contributions from SAIC, which provided content from its Concept of Operations document in support of TFHRC's TOL. The authors also would like to acknowledge the contributions from Joe Peters, director of FHWA's Office of Operations R&D, and Bob Ferlis, technical director of FHWA's Office of Operations R&D. These colleagues conceptualized the TOL and CVHT years ago.

For more information, contact Benjamin McKeever at 202–493–3270 or, or Deborah Curtis at 202–493–3267 or, or Kari Beasley at 703–676–2297 or