Requests are fulfilled as they arrive. As we have a limited inventory, not all equipment may be available.
➔ TECHNICAL TOPICS
What is the communication process between all the equipment?
See Figure 1 in the Appendix below for an example network diagram and communication flow
Why is the OBU not transmitting BSMs?
All OBUs will automatically transmit BSMs once a GPS fix is verified. Ensure the equipment has GPS signal by following the respective instructions below.
How do I check GPS signal on a DSRC device?
When login access to the device is available, GPS signal can be checked with: gpspipe -w
How do I check GPS signal on a C-V2X Device?
When login access to the device is available, GPS signal can be checked with: kinematic-sample-client -a
Where are logs saved on the equipment?
Log locations vary by vendor. A location is indicated at the Appendix section of equipment documentation.
This is possible, with some processing and communication latency. Real-time decoding scripts are available from CAVSupportServices@dot.gov.
How can I check the validity of a received SPaT message?
The validity of a received SPaT message or any other J2735 message can be quickly checked online by pasting the payload to the Marben ASN.1 Messages Decoder website and selecting the Message Frame option.
What information is embedded in a J2735 message?
The J2735 Message Set Dictionary contains all the required and optional fields that are included in each message. The dictionary may be acquired from:
How do we include the vehicle CAN data in the BSM generated by the OBU?
Only certain OBUs are capable of enriching BSMs with CAN data. Please reach out to CAVSupportServices@dot.gov to find out if your OBU is able to do so.
➔ APPENDIX
Abbreviations
BSM
C-V2X
DSRC
GNSS
GPS
IP
MAP
NTCIP
OBU
PoE
PSID
RF
RSU
SAE
SCH
SCMS
SNMP
SPaT
SRM
SSM
TIM
TSC
UTC
Basic Safety Message
Cellular Vehicle-to-Everything
Dedicated Short Range Communications
Global Navigation Satellite System
Global Positioning System
Internet Protocol
Intersection Geometry Message
National Transportation Communications for ITS Protocol
On-Board Unit
Power-over-Ethernet
Provider Service Identifier
Radio Frequency
Roadside Unit
SAE International (formerly Society of Automotive Engineers)
Service Channel
Security Credential Management System
Simple Network Management Protocol
Signal Phase and Timing or Signal Phase and Timing Message
Signal Request Message
Signal Status Message
Traveler Information Message
Traffic Signal Controller
Coordinated Universal Time (also called “Common Universal Time”)