Prevent the need for channel switching (a safety hazard) by designing CV communications to include dual radios in each vehicle
Success Stories from the USDOT’s Connected Vehicle Pilot Program
Made Public Date


United States

Connected Vehicle Pilot Deployment Program: Success Stories


In September of 2015, USDOT selected New York City Department of Transportation (NYCDOT), Wyoming Department of Transportation (WYDOT) and Tampa Hillsborough Expressway Authority (THEA) as the recipients of a combined $42 million in federal funding to pilot next-generation infrastructure and vehicle technology under the Connected Vehicle Pilot Deployment Program.

Lessons Learned

In the area of communications, the CV Pilot sites are using established standards wherever possible, but in many cases, they are trying out standards in the field for the first time, or are implementing messages for which no national or international standards have yet been established.
A key component of connected vehicle communication is Dedicated Short Range Communication (DSRC) in the 5.9 GHz band. Within this band are several channels. Channel 172 is the primary channel, carrying safety-related information and WAVE Service Announcements (WSAs) that advertise the availability of other information and services on other channels. The IEEE 1609.4 standard addresses multi-channel operation for Wireless Access in Vehicular Environments (WAVE), and as such is the "official" set of rules for wireless messages by the CV Pilot sites.

The New York and Tampa teams plan to use dual radios in each vehicle: one to listen to channel 172 and the other to listen to other channels for supplementary information such as Traveler Information Messages. The Wyoming team, on the other hand, originally planned to use a single radio, listening to channel 172 most of the time, but switching to other channels to listen for other messages. Such a channel-switching plan is consistent with IEEE 1609.4 specifications. However, the 1609.4 committee and several manufacturers who are looking ahead to implementation of DSRC required by a ruling from the National Highway Traffic Safety Administration (NHTSA), maintain strongly that it is not safe to switch away from Channel 172, because a safety-critical message on that channel might be missed.

The Wyoming team has agreed to re-design its communications design to include dual radios. However, the discovery that a single channel-switching radio is technically compliant to the 1609.4 standard is a major loophole in the standard that must be addressed and corrected by the 1609.4 committee.

Goal Areas