U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

Skip to content
Facebook iconYouTube iconTwitter iconFlickr iconLinkedInInstagram

Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

Public Roads
This magazine is an archived publication and may contain dated technical, contact, and link information.
Public Roads Home | Past Issues | Subscriptions | Article Reprints | Guidelines for Authors: Public Roads Magazine | Sign Up for E-Version of Public Roads | Search Public Roads
| Current Issue |
Back to Publication List        
Publication Number:  FHWA-HRT-19-003    Date:  Spring 2019
Publication Number: FHWA-HRT-19-003
Issue No: Vol. 83 No. 1
Date: Spring 2019


Making Connections

by Matthew McAllister and Deborah Curtis

The lessons from Denver's collaboration with FHWA's Turner-Fairbank Highway Research Center can help other communities develop a connected vehicle program.

A man in a bucket lift attached to a Denver municipal truck works on the mast arm of a traffic light.
Technicians with Denver's Department of Public Works install a roadside unit at an intersection as part of the city's pilot deployment of connected vehicle technology.

Reading technology magazines may give the impression that all cars will be talking to each other within months. Connected vehicle (CV) technology can enable vehicles to wirelessly communicate with one another, as well as with intelligent infrastructure. But there is a lot for State and local transportation agencies to learn about this technology and its development, applications, installation, and management. The U.S. Department of Transportation and the Federal Highway Administration have resources to help States and municipalities harness this technology, from ongoing projects with the winners of the Smart Cities Challenge to grants and technology demonstrations to help agencies develop and implement CV systems.

One city to take advantage of these resources is Denver, CO. Through a connected system, Denver's Department of Public Works aims to reduce congestion and improve safety. Connected systems can provide more efficient traffic signal priority, or send an alert directly to a vehicle at risk of crashing into a pedestrian who is difficult to see. Vehicles with this technology can more safely pass other cars on the highway, receive alerts about other vehicles in a blind spot, and report icy conditions to the city so snow plows can be sent out.

In 2015, Mayor Michael B. Hancock selected a team of transportation and technology experts to lead Denver's submission to the USDOT Smart Cities Challenge. While Denver did not win the competition, the city was a finalist, and the congestion and safety components of the plan using CV technology became the foundation for a different, successful Federal proposal. “It is a compelling technology for city engineers looking to improve congestion and safety outcomes,” says Michael Finochio, an engineering manager at the Denver Department of Public Works. “We wanted to continue to develop it.”

Denver applied for and received an Advanced Transportation and Congestion Management Technologies Deployment (ATCMTD) grant in 2016. The funding went toward three projects that are part of the city's broader Smart City mission to use technology and data to improve the health, mobility, and safety of all those who live, work, and play in Denver.

Navigating a Tricky Technology

CV technologies and systems are complex and can present a wide array of challenges. For example, Denver's team installed a roadside unit with a wireless radio device but ran into power management issues on the circuit board and had trouble with the communication link to other connected equipment at the intersection. Unknown capabilities and shifting requirements also challenge agencies exploring new technologies.

A group of men and women in front of a planning board.
Denver's Smart City team at their kickoff meeting for the advanced transportation and congestion management technologies deployment program.

“As with all technology projects, though,” says Jim Lindauer of Denver Technology Services, “the best thing to do is to dig in, start small, and learn as much as possible.”

Denver did this by embracing a “living lab” methodology to test innovative ideas and technologies to understand capabilities and limitations before large-scale deployments. The city identified a set of intersections to enable small, rapid tests of new technology, but still ran into difficulties they sometimes struggled to address.

“We were happy to discover that FHWA and the USDOT Intelligent Transportation Systems (ITS) Joint Program Office (JPO) had experts available to help our team adopt agile development practices,” says Finochio.

Agile is a commonly used project management framework in the tech sector where requirements and capabilities are unknown or change frequently--an apt description for Denver's testing environment. In April 2018, experts from FHWA offered a technical assistance session in Denver at which the project team learned about approaches to procurement for and management of agile and open-source projects. The day included a discussion of resources available to help early adopters like Denver.

The most immediately beneficial resource was an equipment loan and technical help desk service run through FHWA's Turner-Fairbank Highway Research Center (TFHRC). Established as part of USDOT's CV Pilot Deployment Program, this service offers agencies short-term loans of the latest equipment and addresses their frequently asked questions based on lessons learned from other projects.

Denver was early enough in the process that the team did not know exactly what requirements to include in a solicitation for devices. “We started testing to see how these devices would work with our existing technologies in a living lab environment,” says Emily Silverman, the Smart City program manager in Denver. “The equipment loan program was the perfect solution. Within a few days, devices were on their way, free of charge, to Denver.”

Borrowing equipment from TFHRC includes the benefit of direct communication with technical support staff. TFHRC's Saxton Transportation Operations Laboratory works with a contractor to offer Connected and Automated Vehicle Support Services, which includes an online interface at www.pcb.its.dot.gov/CAVSupportServices.aspx. Denver's technical team collaborated with the support staff to get all of the loaner equipment working with the city's traffic signal controllers, including older generation controllers Denver's team had assumed would not be supported.

“This achievement was a big deal for Denver,” says Dave Edinger, Denver's chief information officer. “Our Smart City team operates from a set of core values, including supporting multivendor interoperability and avoiding lock-in.”

An Open-Source Solution

Denver's team wanted to avoid overreliance on any given technology or vendor and to deploy solutions that maximize interoperability, that are based on standards, and that maintain city and county ownership of the data. Fortunately, TFHRC had a solution: a vehicle-to-everything (V2X) option called V2X Hub, an open-source tool available at www.pcb.its.dot.gov/CAVSupportServices.aspx.

A man holding open a truck door, showing electronic test equipment inside.
Denver is testing technology that enables two-way communication among vehicles, infrastructure, and traffic signals.

At first glance, V2X Hub may appear to be simple translation software for CV standards to communicate with traffic signal controller protocols. However, that is just the foundation for its capabilities. It provides a platform for public and private partners to work together on applications that improve congestion and safety outcomes. “V2X Hub is a Rosetta stone for the connected vehicle system,” says Silverman.

In Denver, the V2X Hub software enabled the city to achieve wide-ranging interoperability between traffic signal controllers and roadside units. The team deployed the code on a single-board Linux processor and placed it on the same network switch as the traffic signal controller and roadside unit.

V2X Hub also aligns with another one of Denver's core Smart City values: to be “open by default.” To the maximum extent practical, the city chooses open source solutions over closed proprietary ones, and open data over siloed and closed data. As an open-source tool, V2X Hub enables cities, States, and private companies to build additional plug-ins for CV apps and other functionality. By separating the application layer from the hardware layer--creating tools that can work with a wide variety of devices and equipment--V2X Hub offers Denver the capability to work with multiple vendors to meet the city's needs, incorporate data from other devices at intersections, and build software with collaborators across the country.

This level of collaboration and integration saves money, avoids duplicative efforts, and makes it easier for subsequent cities to get started. “Historically, technologies to improve transportation have been proprietary, making the development and adoption of new technologies more difficult and expensive,” says Chris Stanley, senior director of Surface Transportation Research at Leidos and program manager for the Saxton Lab. “By creating standards and an open architecture for interoperability, USDOT laid a foundation that's accelerating the adoption and open-source development of solutions by hundreds of organizations throughout the country. The sharing of information and code has enabled contributors to develop new solutions much more quickly, efficiently, and economically.”

Expanding Efforts

Denver's Smart City program is providing actionable data to frontline employees, combining institutional knowledge with technology advances to connect residents to city services. The city's team is excited to build solutions with other communities across the country, continue to collaborate with FHWA, and accelerate the adoption of CV solutions to make the city's transportation system safer and more efficient.

To expand communication and collaboration even further, TFHRC's Saxton Lab launched the V2X Hub User Group. For more information, go to www.pcb.its.dot.gov/CAVSupportServices.aspx.

Tricia Sergeson, a transportation specialist with FHWA's Colorado Division, worked with Denver's Smart City team. She says, “Working with Denver on the connected vehicle deployment has been an excellent example of how USDOT has been able to collaborate and leverage the great research and expertise of the TFHRC, the ITS JPO, FHWA's field division offices, and the Resource Center to help deploy new technologies and innovation.”

Look for more features on CV in upcoming issues of PUBLIC ROADS.

Matthew McAllister is the Smart City project manager for the city of Denver, overseeing the connected vehicle Federal grant program. He previously served as the special assistant and policy advisor to the U.S. Chief Technology Officer in the White House Office of Science and Technology Policy. He is a graduate of the University of Colorado Boulder.

Deborah Curtis has been a re-search engineer in FHWA's Office of Operations Research and Development for 28 years. She leads the Connected and Automated Vehicle Support Services program within the USDOT as well as other infrastructure-based connected and automated vehicle research. She is a civil engineer and graduate of West Virginia University.

For more information, see www.pcb.its.dot.gov/CAVSupportServices.aspx or contact Aaron Greenwood at CAVSupportServices@dot.gov.



Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101