Federal Highway Administration National Dialogue on Highway Automation: November 14-15, 2018 Infrastructure Design and Safety Workshop Summary

Breakout Session II: Infrastructure and Automated Vehicles

This section summarizes the stakeholder discussion from the first breakout session. The following questions were asked:

• What are the long- and short-term impacts of AVs on roadways and structural infrastructure? For example, what are impacts of truck platooning on bridges, pavement rutting, etc.?
• What are possible changes in structural and operational infrastructure design and asset management practices to address AVs and how could they be implemented?
• How will these changes impact existing standards, manuals, and other national guidance for highway design, highway maintenance, and traffic control?

Infrastructure Standards Development and Updates Should Become More Nimble and Flexible to Keep Pace with AV Technology

Existing infrastructure standards may need to be modified to meet the needs of rapidly changing technology, but the development of (or update to) a standard can take years to complete. As more automated vehicles enter the fleet, participants were concerned that standards such as the Manual of Uniform Traffic Control Devices (MUTCD) may have difficulty meeting the needs of the rapidly changing technologies in automated vehicles. As a result, several suggested pursuing a more flexible and nimble standards approach to adapt to AVs and other emerging transportation technologies. This could include shorter periods between standards updates, for example. Finally, as standards and guidebooks are revised, State DOTs may also need to update their asset management plans more often.

Consistency in Infrastructure Standards Can Support Seamless AV Operation Across Geographic Boundaries

Although national standards exist, such as the MUTCD, they allow for flexibility and options. Infrastructure owners and operators implement their own versions of these standards, which can include slight variations. Workshop participants expressed that greater consistency in standards and the adherence to them can support AVs to efficiently operate between geographic boundaries. For example, certain roadway elements, such as signage and line striping could be more consistent (the MUTCD includes standards for four-inch and six-inch line striping).

Built Environment Must Support Changes in Traffic Composition and Roadway Use

As AVs are more widely integrated onto the roadway infrastructure, the design of roads, bridges, and pavements may need to change. Several examples suggested by participants included: development of AV-only lanes added to limited-access roadways, different bridge designs to accommodate vehicle platoons, and variations in curb design to allow for less parking and more pick-ups and drop-offs. Others identified pavement rutting as a potential concern if there is no wheel path variation among AVs. Although these infrastructure design changes may not be necessary in the near future, participants generally agreed that road infrastructure design guides may require revisions to reflect changes in the use of the roadways.

Infrastructure Considerations for Truck Platooning Applications Require Further Research

The nature of automated truck platooning applications may introduce different challenges for pavement maintenance, bridge design, and ramps. Truck platoons were identified as potentially causing load issues for bridges, as they were not initially designed with automated platoons in mind. Some participants noted that truck platoons could also affect the harmonics of a bridge, which could ultimately lead to a collapse. Traveling through ramps, at-grade railroad crossings, and congested roadways were also identified as specific scenarios where truck platoons could interrupt traffic flows, causing queues and crashes. Overall, workshop participants stated the need for more research and testing in this area to better understand how automated truck platooning applications could be integrated safely into the existing roadway infrastructure.

Actively Engaging with and Having Transparency in Asset Management Plans Can Also Support AVs

Workshop participants discussed the importance of actively engaging with asset management plans, including comprehensive asset inventories. Several expressed that IOOs could have more frequent inventory and condition assessments to enable their asset management systems to better reflect real-world conditions and to support improved decision making. Some noted that, as AV technology advances, data collected by AVs could support the inventory and conditions assessments. To provide the conditions that AVs may need, IOOs may need more proactive asset management. Additionally, participants noted that IOOs need to be more transparent about their asset management plans and communicate with stakeholders about the decision-making process. Participants suggested that many stakeholders, including OEMs and the public, often do not understand why one infrastructure project is occurring instead of another. In addition, AV industry stakeholders could benefit from seeing DOT guidelines for asset management, as some may not necessarily understand how asset management is performed.

OEMs and IOOs Should Communicate to Provide Consistent Digital Representations of Infrastructure

In addition to the importance of physical infrastructure, the digital environment could be equally important in the success of AVs. Workshop participants suggested that IOOs and industry should work together to develop a consistent base map and representation of the built environment used for AVs. Yet, the discussion revealed significant uncertainty around such a development and how it would be funded. Overall, a knowledgeable workforce is required to develop and maintain the digital infrastructure, which participants suggested should be a consideration for public agencies as they explore their future workforce needs.

Understanding the Necessary Infrastructure Condition for AVs and Available Funding Remains a Gap

It remains unclear how much of the existing infrastructure should be improved to facilitate the widespread integration of AVs, if at all. Entities developing AV technology are designing the systems to be able to function fully on the current roadway infrastructure as it exists today. Most participants sought more research to determine whether infrastructure minimum conditions should be considered. Yet, there was significant concern about funding constraints and the ability of IOOs to fund any necessary infrastructure improvements for AVs. Participants pointed to how fiscal uncertainty poses a challenge for planning investments in the long term.