NCHRP 23-10 - Evaluation and Synthesis of Vehicle-to-X 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 report, 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. View or download the March 2020 report HERE.

A summary of the reply comments submitted to the FCC in March and April 2020 in connection with the NPRM is available HERE.

A brief fact sheet on the NPRM and V2X technologies is available HERE.

Operations Area of Practice

  • Automated vehicles
  • Automatic Vehicle Location (AVL)
  • Connected Vehicles

Organizational Capability Element

  • Vehicle Systems/Connected Vehicles

Content Type

  • Presentation

Publishing Organization


Document Downloads

Project Website

Website link

Issue Date
March 1st, 2020
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