Leverage Supplementary Communication Protocols To Disseminate Traveler Information Messages (TIMs) Beyond the Deployment Region To Maximize Impacts of Connected Vehicle Technologies.

Lessons Learned Logbook Synthesis from the Three USDOT Connected Vehicle Pilot Deployments.

Date Posted

Connected Vehicle Pilot Deployment Lessons Learned Logbook Synthesis

Summary Information

The U.S. Department of Transportation initiated three Connected Vehicle Pilot Deployments (CVPD) in September 2015 in New York City, Wyoming, and Tampa Hillsborough Expressway Authority, FL, with the aim of testing and implementing connected vehicle applications, transforming research ideas into practical solutions. These CVPDs served as a large-scale "system of systems" that incorporated both technical and non-technical aspects. This study provided useful solutions and lessons learned captured by the three CVPD sites in their Lessons Learned Logbooks (LLLs) to growing early and future CV deployer community to help avoid potential deployment pitfalls and facilitate efficient and cost- effective CV deployments. These lessons learned were presented to attain a more universal and compatible standard in the operation of CV deployment. Additionally, the study noted that although Dedicated Short-Range Communications (DSRC) were replaced by Cellular Vehicle-to-Everything (C-V2X), similar challenges and lessons could be expected.

Lessons Learned

  • Leverage supplementary communication protocols to disseminate traveler information messages (TIMs) beyond the deployment region to maximize CV impacts. When there were a limited number of roadside units (RSUs) in the CVPD sites, the TIMs were restricted to the region of the deployment corridor. To address this limitation, on board units (OBUs) and dual communication media (e.g., DSRC and satellite communication) could be used to send TIMs to CV equipped vehicles. This method allowed a more resilient system when one communication media was not operative.
  • Plan for extensive CV device procurement to ensure proper functionality, and source vendors and suppliers at early stages to solve possible software issues. The pilot conducted by the Wyoming Department of Transportation (DOT) team implemented pre-delivery testing to avoid issues in missing files or functionality. NYCDOT conducted analysis on the CV deployment vendors and their sub-suppliers and found that there was much reliance on the sub-vendors when adjusting software for location accuracy and security. THEA selected the best suppliers after conducting multiple on-the-road tests of the system.
  • Incorporate existing standards into the system architecture and design process while being mindful of potential gaps, inconsistencies, and ambiguities in standards, as well as the possibility of varying interpretations. THEA avoided using unpublished standards. If a USA standard was not available, it was recommended to use an international standard or the USDOT V2X Hub publication. It was crucial to address requirements that improved interoperability and collaboration with standards committees and developers to add compatibility to older standards.
  • Maintain a stable telecommunications network to avoid disruptions to or from other devices. Collaborate with equipment vendors and service providers, perform network testing, and establish monitoring processes as done by WYDOT and NYCDOT to ensure reliable and secure CV communication systems that have minimal downtime.
    • NYCDOT found that that certain network monitoring protocols such as SNMP v3 were not supported on some devices at the time of deployment thus thorough checks of receiver and transmitter elements were required.
    • The THEA pilot used DSRC sniffers to detect radio interference and unauthorized broadcasts. 
  • Use over-the-air (OTA) updates to download firmware and conduct log offloading. Assessing and testing OTA download speeds early in the design process allowed for issue identification and provided site teams time to collaborate with vendors on solutions, ensuring timely downloads of certs, software updates, and log file uploads.
  • Test the accuracy of CV device location. Certain safety applications needed highly location accuracy, where smart phone GPS was insufficient. The NYCDOT team found that implementing “V2XLocate” (a solution using time of flight from RSU transmissions) had sufficient location accuracy when operating many of the V2V and V2I safety applications. multiple sensors and laser light were also used to improve GPS location accuracy.
  • Define data requirements early in the project to minimize communication, processing, and storage costs. Defining data needs earlier in the project helped CV-Pilot sites generate quality and appropriate data that supported their performance measurement and evaluation objectives. Furthermore, costs associated with communications, data storage, and processing were also minimized by limiting data collection volumes where appropriate.
  • Incorporate non-CV sensor data to efficiently provide sufficient information for CV applications, ensuring they meet operational and performance goals. Some deployed CV applications required a high penetration rate of CVs to fulfill their intended functions. Therefore, pilot projects like the Tampa CV deployment needed to supplement data from other sources, such as cameras and speed radars. One data limitation was addressed by using video detection to support a multimodal intelligent traffic signal system (MMITSS) application.
  • Pay attention to antennae design, placement, and product quality. Trucks and buses of varying sizes had distinct antenna configurations and wiring needs, which differed from those on light-duty vehicles.
  • Test the function of the Security Credentials Management System (SCMS) prior to deployment. The CVPD teams worked with the USDOT SCMS developer and security vendors to develop a national SCMS, however, certain features of the SCMS impacted local system operations that required deployers to revert to an earlier version of the SCMS. NYCDOT avoided SCMS delay by addressing security for the site deployment, which included the Transportation Management Center (TMC), system access, and device/network security.

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