Lesson

Refine proper antenna placement on connected vehicles (particularly commercial vehicles) to reduce DSRC ‘shadow’ areas where DSRC signal is degraded.

Lessons Learned from the Design/Build/Test Phase of the USDOT’s Connected Vehicle Pilot Program.


12/13/2018


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Lesson Learned

The following considerations summarize the CV Pilots’ experiences with mounting and installing CV devices along roadways and inside vehicles.

Utilize professionals where possible for installations
    The OBU installations should be done in a professional setting with certified vehicle mechanics to prevent unintentional modifications or damage to participants’ vehicles. In particular, deployments with a large number of vehicles should utilize standardized installation and checkout procedures to ensure efficiency.
    • NYC used the City’s mechanical installers for the installations of the OBUs on the NYCDOT fleet vehicles. NYC planned on contracting out the installation of their onboard devices for the nearly 8,000 vehicles to outside professionals after concluding that the City’s mechanical installers had insufficient resources to address the fleet size within the time constraints.
    • The THEA team partnered with nearby Hillsborough Community College (HCC) to use their Master Mechanic Program facility and staff to install the OBUs, giving the students real-world experience and helping reduce labor costs.
    • WYDOT and their partner Trihydro were each responsible for installing the OBUs in their own vehicles, though Trihydro contracted with a local audio installer for the installations. WYDOT staff were used to install the OBUs in the WYDOT fleet vehicles.
Recognize that different vehicle types require different hardware and installations processes
    There is no installation methodology that applies across-the-board as each vehicle type has different needs.
    • NYCDOT elected to install an audio-only human-machine interface (HMI) in the participating vehicles after stakeholders indicated that they already had several other screens competing for their attention.
    • The THEA Pilot on the other hand included an audio and visual HMI that displayed messages on the driver’s rearview mirror. The configuration in Tampa’s streetcars was particularly unique as they required 2 OBUs and HMIs (one on each end) for when the streetcar reverses the direction of travel and the driver moves to the opposite side.
    • The WYDOT Pilot’s HMI was capable of audio and visual alerts as well as displaying different messages to drivers. The semi-trucks necessitated that the OBUs and associated hardware be installed on the cab of the trucks instead of the trailer since the trailers are always changing.
Check vehicles for pre-existing safety systems that may interfere with an evaluator’s ability to isolate impacts of the CV applications
    If an evaluation is being performed, it is strongly recommended that aftermarket CV technologies not be installed on vehicles that have existing safety system (such as Mobileye or Kaptyn systems) since many of the warning types will be redundant with the CV safety applications. Having redundant technologies that serve the same purpose on the CV equipped vehicles will interfere with an evaluator’s ability to isolate impacts of the CV applications.

    NYCDOT confirmed that their partners Metropolitan Transportation Authority (MTA) and the Taxi and Limousine Commission (TLC) had some vehicles fit with pre-existing safety systems. The NYC Pilot requested that MTA vehicles with these systems be excluded from the Pilot. However, the same blanket-ban was not able to be made for the TLC vehicles as the taxis have different owners. To address the issue of redundant safety systems in the TLC vehicles, the NYC team provided installers with a pre-install checklist that included a check item for pre-existing safety systems. If such pre-existing safety system were found during installation, an OBU was not installed on the vehicle.

Be sensitive to the power drawn by in-vehicle devices to avoid vehicle power-drain
    Fleet vehicle owners involved in the pilot originally desired a zero quiescent current draw – though this was not feasible with the selected devices. As a result, the pilots restricted the current-draw of their OBU vendors (NYCDOT restricted their onboard unit vendors to a current draw of 25 micro-amps).
    To prevent subsequent maintenance issues, it was standard operating procedure for the Pilots to first check the vehicle’s electrical system (including battery and alternator/charger) before installing any CV equipment and installers would not proceed if any issues were found. Additionally, crews would cease installation when any vehicle’s indicator lights (e.g. check engine) were activated.

Perform appropriate calibration procedures for all onboard technologies
    Following the installation of the devices in private vehicles, the Tampa installation crews drove the vehicles in "figure 8s" to calibrate the accelerators in the OBUs. However, this method was not a practical approach for the NYC vehicles, especially with their MTA buses. NYC later proposed mounting an OBU on a gimbal with a known orientation for proper calibration. Additionally, NYC had their vendors provide a calibration indication to their device’s system logs at each start-up.

Refine proper antenna placement to reduce communications interferences
    The location of the antenna is critical to ensure continuous wireless communication without loss of signal strength. The New York City and Tampa teams found that for light-vehicles, antennas mounted near the rear-center of the rooftop was most ideal. However, large vehicles, such as the semi-trucks that the WYDOT pilot installed onboard units on, often have "self-blocking" physical elements that obstruct the vehicle’s own DSRC antennas from direct line of sight with other vehicles. This resulted in "shadows" for the Wyoming vehicles that prevented remote vehicles from properly communicating with the trucks. To alleviate this effect, the Wyoming team worked with USDOT’s communication experts to perform numerous tests in Wyoming and at the Aberdeen Proving Grounds. The testing concluded that the effect of the DSRC shadows could be best alleviated by mounting the antennas on the side mirrors of the semi-trucks.


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Source

Connected Vehicle Pilot Deployment Program Driving Towards Deployment: Lessons Learned from the Design/Build/Test Phase

Author: Thompson, Kathy

Published By: USDOT Federal Highway Administration

Source Date: 12/13/2018

Other Reference Number: FHWA-JPO-18-712

URL: https://rosap.ntl.bts.gov/view/dot/37681

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Lesson Analyst:

Kathy Thompson


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Lesson Categories

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Application Areas

Intelligent Transportation Systems > Driver Assistance > In-Vehicle Monitoring

Intelligent Transportation Systems > Arterial Management > Enforcement > Speed Enforcement

Intelligent Transportation Systems > Arterial Management > Enforcement > Traffic Signal Enforcement

Intelligent Transportation Systems > Arterial Management > Surveillance > Traffic

Intelligent Transportation Systems > Arterial Management > Traffic Control > Advanced Signal Systems

Intelligent Transportation Systems > Crash Prevention & Safety > Collision Avoidance > Forward Collision Warning

Intelligent Transportation Systems > Crash Prevention & Safety > Collision Avoidance > Lane Change Assistance

Intelligent Transportation Systems > Crash Prevention & Safety > Collision Avoidance > Obstacle Detection

Intelligent Transportation Systems > Crash Prevention & Safety > Collision Avoidance > Rear Impact Warning

Intelligent Transportation Systems > Crash Prevention & Safety > Intersection Collision Warning

Intelligent Transportation Systems > Crash Prevention & Safety > Pedestrian Safety

Intelligent Transportation Systems > Crash Prevention & Safety > Road Geometry Warning

Intelligent Transportation Systems > Driver Assistance > Driver Communication

Intelligent Transportation Systems > Driver Assistance > Object Detection

Intelligent Transportation Systems > Emergency Management > Emergency Medical Services

Intelligent Transportation Systems > Emergency Management > Response & Recovery > Evacuation & Re-Entry Management

Intelligent Transportation Systems > Emergency Management > Response & Recovery > Emergency Traveler Information

Intelligent Transportation Systems > Road Weather Management > Surveillance, Monitoring, & Prediction

Intelligent Transportation Systems > Road Weather Management > Information Dissemination

Intelligent Transportation Systems > Roadway Operations & Maintenance > Work Zone Management > Speed Enforcement

Intelligent Transportation Systems > Transit Management > Operations & Fleet Management > Transit Signal Priority

States

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Countries

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Focus Areas

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Goal Areas

Safety
Mobility

Keywords

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Lesson ID: 2019-00892