Lesson

Connected Vehicle Vehicle-to-Infrastructure deployment in Tallahassee, FL realizes importance of field reviews, placement of devices, and roadway geography.

As part of the Signal Phase and Timing (SPaT) Challenge, the City of Tallahassee is working to provide SPaT and geographic intersection description information to motorized and non-motorized road users through a connected transportation system.


04/10/2019
Tallahassee; Florida; United States


Background (Show)

Lesson Learned

FDOT engaged Florida State University to evaluate the operational and safety benefits of the SPaT applications along US 90. The short-term goal is to verify if SPaT will work effectively in hilly and forested terrain along US 90, while the overall long-term goal is to evaluate Dedicated Short-Range Communications (DSRC) efficiency and safety for road users along a signalized arterial corridor.

Some of the major lessons learned during the process were the following:
  • Federal Communication Commission (FCC) Licensing: The state of Florida has a statewide FCC license for testing DSRC. As DSRC units are installed, only specific site information is needed to complete the licensing process. FDOT’s statewide license will save time for any new deployment projects in the state.
  • Field Review: Conducting a field review of the corridor is important. RSUs are omni-directional and can emit as far as 300 meters (984 feet). However, consideration needs to be made for line of sight issues such as vegetation, road curvature, signs and intersection geometry. If a line of sight issue exists, adding another RSU to the signal location should be considered.
  • RSU Placement: The US 90 project tested RSU antennas on both mast arm and span wire configurations, and both worked well. Each DSRC antenna should be placed at a location to capture all approaches and follow the FCC requirements on antenna height placement.
  • Cabinet Location: The antenna should be placed on a mast arm on the same side of the roadway as the traffic signal cabinet location to minimize cabling or adding underground conduit.
  • Cabinet Space: For some CV-ready controllers such as the 2070 or Advanced Traffic Controller (ATC), as was the case in US 90 project, there is minimal space required for Power over Ethernet (PoE) injector placement. For others, a small digital versatile disc (DVD) player may be needed to convert controller messages to Society of Automotive Engineer (SAE) requirements, and to send to RSUs.
  • MAP Data Preparation: This project used the United States Department of Transportation’s (USDOT) mapping tool to develop map data for all 22 locations. Interested entities should consider working with vendors to create MAP data that are interoperable, per the SAE standards.
  • FCC-Certified RSUs and On-board Units (OBUs): It is important to obtain the FCC licensing for both RSUs and OBUs by FCC-approved labs. Ask vendors to provide certificates during the procurement process and to include them in their document submittal.
  • Vendor Training and As-Needed Installation Support: Vendor training and field technical support (as needed) should be included in the contract. They should be identified as separate bid items.
  • Future Compatibility: Consider dual-band RSUs that have cellular/Wi-Fi capability as well as 5.9 GHz DSRC communications.


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Source

US 90 SIGNAL PHASE AND TIMING (SPaT) PROJECT: CASE STUDY

Published By: National Operations Center of Excellence (NOCoE)

Prepared by the Florida DOT

Source Date: 04/10/2019

URL: https://transops.s3.amazonaws.com/uploaded_files/Florida%20DOT%20Case%20Study%20-%20US%2090%20SPaT.pdf

Lesson Contacts

Lesson Analyst:

Kathy Thompson


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States

Florida

Countries

United States

Goal Areas

Mobility

Keywords

coordinated signals, signal coordination, centralized signal control, signal synchronization, traffic signals, advanced signal control, signal timing optimization, coordinated signal control, advanced signal controller, traffic signal retiming, retiming

Lesson ID: 2019-00900