While the connected vehicle technology debate – DSRC or cellular – continues to slow down government officials’ and auto makers’ direction for connected vehicles (CVs), highway operators are moving ahead with DSRC-based vehicle-to-infrastructure (V2I) demonstrations projects. The objective is to gain technical and operating experience with V2I and produce some immediate benefits from the projects.
In the latest AV 3.0 policy document, the US Department of Transportation (USDOT) addressed the current relationship between connected and automated vehicles. “Communication both between vehicles [V2V] and with the surrounding environment [V2X] is an important complementary technology that is expected to enhance the benefits of automation at all levels, but should not be – and realistically cannot be – a precondition to the deployment of automated vehicles.”
The USDOT had no choice but to take this position given that its 2016 rule-making for light vehicles to include V2V communications no longer has a completion date. Meanwhile Level 4 autonomous vehicle (AV) testing continues in cities across the US.
In the US there are more than 70 V2X pilot project deployments using DSRC wi-fi for connectivity. A few of these are supported by USDOT grants, but many more are funded by state DOTs or cities.
In most cases, roadway agencies control the installation of roadside devices, but struggle to outfit a meaningful number of connected vehicles. State and locally funded projects focus on installing DSRC radios in fleet vehicles to gain operational experience, but also to provide immediate benefits to functions such as bus and snowplow signal priority.
Two major federally funded connected vehicle projects in New York City and Tampa, Florida, have greater connected vehicle scale, anticipating almost 10,000 connected vehicles between the two deployments. At this scale, the CV information gained by roadway operators will be much greater, and both city deployments anticipate larger scale roadway safety and operational benefits created by the real-time data transmitted by vehicles. Cellular communications companies are beginning to roll out 5G service.
5G promises 10 times faster data speed, less processing delay and greater connectivity. Moreover, early tests of cellular V2V and V2I have shown that this new technology can connect vehicles and infrastructure locally without depending on the cellular network. At the same time, data can be uploaded to the cellular cloud without the use of roadside units and construction of a new fiber backhaul system required by DSRC.
There are possible benefits as AVs are connected, for example a bigger picture look down the road to alert a vehicle to congestion or safety problems, and the platooning of vehicles to improve lane capacity. But given the CV technology dilemma, the reluctance of the federal government to mandate installation of connectivity on new vehicles, the slow US fleet uptake of connectivity and unresolved cybersecurity concerns, AVs will likely be dependent on onboard sensors for at least a decade after their introduction.
Don Hunt is a transportation consultant and former director of Colorado DOT; firstname.lastname@example.org