STATUS: Project is complete. The final report and a link to a video presentation summarizing the project are available here: https://www.trb.org/Publications/Blurbs/182571.aspx
The intelligent transportation system (ITS) band, also known as the “5.9 GHz band” (which consists of a 75 MHz band between 5.850-5.925 GHz), was allocated by the Federal Communications Commission (FCC) in 1999 for use by dedicated short-range communications (DSRC) services. The FCC dedicated the ITS band for “operations related to the improvement of traffic flow, traffic safety and other intelligent transportation service applications”. Other communication technologies, such as cellular and wifi networks, can also be used for transportation purposes. These technologies include vehicle-to-vehicle technologies (V2V) and vehicle-to-infrastructure technologies (V2I)—collectively known as V2X.
However, there are important differences between technologies that are relevant for transportation agencies. For example, DSRC has low latency compared to current cellular technology, which can support nearly instantaneous communication of obstacles or other roadway users (e.g., pedestrians or people on bicycles), an important consideration for safety applications. Cellular technology, however, has been widely adopted by—and is carried by—the users of the transportation system, a potential advantage for accelerating implementation. Understanding the differences between technologies supports the careful consideration of tradeoffs and future implications when forming policy positions and interacting with private sector vendors and regulatory entities (e.g., the FCC).
State DOTs focused their pilot and implementation efforts on technologies that used DSRC. In the fall of 2019, the FCC set in motion a process to reallocate a portion of the 5.9 GHz band. This change is anticipated to have important implications for current and future investments by state DOTs, requiring these agencies to realign their pilot and testing activities, re-visit ongoing procurement of devices and software, and transition existing DSRC installations to C-V2X.
The ongoing FCC action is only part of a highly dynamic decision-making environment for state DOTs. Private sector entities, including vehicle manufacturers, ITS service providers, application developers and others, are actively developing V2X technologies and services which will shape the future of the transportation network. To be effective, those in leadership positions at state DOTs need to be well informed on the evolution of V2X technologies, the perspectives of partners and stakeholders, and developments on the regulatory landscape.
NCHRP Project 23-10 developed a series of materials, which were released over the course of the project, to provide real-time information and resources for state DOTs to understand and respond to FCC actions that unfolded over an 18-month period from fall 2019 through May 2021. The project report compiles these materials to provide contemporaneous documentation of stakeholder perspectives on a landmark change in the regulation of critical infrastructure for ITS and CAVs. The report also includes a forward-looking Executive Summary that describes how these materials can be used to support current and future state DOT decision making on the development, procurement, testing, piloting, and deployment of CAV technology.