  The safety, mobility, environmental, energy, and economic benefits of
transportation systems, which are the focus of recent connected vehicle (CV)
programs, are potentially dramatic. However, realization of these benefits
largely hinges on the timely integration of digital technology into upcoming as
well as existing transportation infrastructure. CVs must be enabled to
broadcast and receive data to and from other CVs [vehicle-to-vehicle (V2V)
communication], to and from infrastructure [vehicle-to-infrastructure (V2I)
communication], and to and from other road users, such as bicyclists or
pedestrians (vehicle-to-other road users communication). Further, the
infrastructure and transportation agencies that manage V2I-focused applications
must be able to collect, process, distribute, and archive these data quickly,
reliably, and securely. This paper focuses on V2I applications and investigates
current digital roadway infrastructure initiatives. It highlights the
importance of including digital infrastructure investment alongside investment
in more traditional transportation infrastructure to keep up with the auto
industry push toward increasing intervehicular communication. By studying
current CV testbeds and smart-city initiatives, this paper identifies digital
infrastructure being used by public agencies. It also examines public agencies
limited budgeting for digital infrastructure and finds that current expenditure
is inadequate for realizing the potential benefits of V2I applications.
Finally, the paper presents a set of recommendations, based on a review of
current practices and future needs, designed to guide agencies responsible for
transportation infrastructure. It stresses the importance of collaboration for
establishing national and international platforms for the planning, deployment,
and management of digital infrastructure to support connected transportation
systems.
