On June 30, 2020, the Wyoming DOT’s (WYDOT) Connected Vehicle (CV) Pilot expanded Traveler Information Message (TIM) dissemination capability beyond the spatial limits of the I-80 CV Pilot corridor. This expansion allows for all CV-equipped WYDOT vehicles and fleet partners (mostly in the oil industry who travel throughout the state) to receive TIMs on all of the state’s highway facilities.
WYDOT CV Pilot vehicles are equipped with either Lear or Sirius XM On-board Units (OBU). Both OBUs allow equipped vehicles to receive TIMs through either Dedicated Short-Range Communication (DSRC) or satellite communication. The contents of a TIM include inclement weather warnings and advisories, recommended speeds, road closure notifications, parking/services information for trucks, vehicle restrictions, and others. The need for dual communication media is due to the prohibitive cost of installing Roadside Units (RSU) along the entire 402-mile I-80 CV Pilot corridor. Therefore, on segments along the I-80 CV Pilot corridor where RSUs are not present, equipped vehicles receive TIMs through satellite communications instead of DSRC.
The generation and dissemination of TIMs involves several sequential steps as well as the use of WYDOT CV Pilot infrastructure and back-office systems in charge of specific processes. First, the Operational Data Environment (ODE) receives data collected with CVs through the RSUs (mainly basic safety messages), checks its quality, and then shares with other WYDOT CV Pilot sub-systems such as the Pikalert and Data Broker (DB). The Pikalert system assigns received data to 1-mile segments on I-80 and fuses CV (from the ODE) and non-CV weather data (from other weather sources and DB) to produce warnings, advisories, and 72-hour forecasts for adverse weather. These weather warnings, advisories, and forecast are sent to the DB. Next, the DB receives information from the Pikalert system, ODE and some external systems and analyzes them. The DB contains logic which determines when a situational data message should be issued and compiles TIMs that need to be sent to the ODE. The DB sends TIMs to the ODE for ASN.1 encoding and subsequent transmission to CVs from RSUs. For CVs that are outside of the DSRC communication range, the ODE sends TIMs to Trihydro’s Situation Data Exchange (SDX) and the SDX in turn transmits these TIMs to CVs through satellite communication.
The WYDOT CV Pilot’s approach for providing statewide traveler information was relatively inexpensive but technically sophisticated. The exorbitant costs associated with RSU procurement and maintenance made it necessary to carry out this expansion without any increase in RSU footprint in the state. In addition, the current freeze on DSRC licensing by the Federal Communications Commission (FCC) implies that acquiring and installing additional RSUs would not have been possible even if funds were available. Subsequently, WYDOT CV Pilot relied on the satellite communication capabilities of equipped vehicles to transmit TIMs beyond the geographical boundaries of the I-80 CV Pilot corridor.
To achieve this expansion, WYDOT CV Pilot mapped out all the mile marker locations across the state highways using the Pikalert system. This required conversion of the mile marker locations from the state highway reference system to a geographical coordinate system of latitudes and longitudes beginning and end points. In addition, the WYDOT CV Pilot created rules for data aggregation by time (i.e., how often data is aggregated) and location (i.e., length of analysis segment). Once this was done, WYDOT CV Pilot used the same back-office systems and processes used in sending TIMs within the pilot corridor to send TIMs statewide.
The running of statewide TIMs has been integrated into the operations of WYDOT’s Traffic Management Center (TMC) in Cheyenne, Wyoming. WYDOT plans to continue providing equipped vehicles with statewide traveler information beyond the duration of the CV Pilot.
