Evaluation and Synthesis of Connected Vehicle Communication Technologies

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). Developments in V2X technologies, the regulatory landscape, and investment choices by private sector entities (vehicle manufacturers, ITS service providers, and others) are creating a highly dynamic decision-making environment for state DOTs. To be effective, those in leadership positions at state DOTs need to be well-informed on current and emerging trends related to V2X technologies and understand how these trends should be considered in policies and decisionmaking. In February 2020, the FCC published a Notice of Proposed Rulemaking (NPRM) that would reduce the set-aside from 75 MHz to only 30 MHz for CV technologies, establish specific technology requirements within that allocation, and open the rest of the spectrum to unlicensed Wi-Fi devices (FCC ET Docket No. 19-138). The NCHRP 23-10 white paper, V2X Communications in the 5.9 GHz Spectrum: March 2020 Update, provides essential information about V2X technologies, a timeline of developments in V2X technologies and implementation, and a discussion of the anticipated effects of the proposed changes along with a summary of stakeholder comments submitted in response to the current FCC NPRM. A summary of the reply comments submitted to the FCC in March and April 2020 in connection with the NPRM is available. A brief fact sheet on the NPRM and V2X technologies is available. On November 18, 2020, the FCC took further action toward realigning the 5.9 GHz band by issuing a Further Notice of Proposed Rulemaking (FNPRM). A brief fact sheet on the November action is available. A second NCHRP 23-10 white paper, V2X Communications in the 5.9 GHz Spectrum: New Directions, Opportunities, and Challenges, describes potential scenarios and resultant business decisions related to the reallocation of the 5.9 GHz spectrum. The white paper provides infrastructure owners and operators, including state DOTs, with information on licensing, deployment, application, and planning issues for V2X, with a focus on three priority applications: Red Light Violation Warning, Reduced Speed Zone Warning, and Connected Automation. The March 2021 white paper is available.


  • English


  • Status: Completed
  • Funding: $350000
  • Contract Numbers:

    Project 23-10

  • Sponsor Organizations:

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  United States  20001

    American Association of State Highway and Transportation Officials (AASHTO)

    444 North Capitol Street, NW
    Washington, DC  United States  20001

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Project Managers:

    Hartell, Ann

  • Performing Organizations:


  • Principal Investigators:

    Kuciemba, Stephen

  • Start Date: 20200224
  • Expected Completion Date: 20210601
  • Actual Completion Date: 20210601

Subject/Index Terms

Filing Info

  • Accession Number: 01731870
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 23-10
  • Files: TRB, RIP
  • Created Date: Feb 24 2020 3:41PM