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U.S.
Department of Transportation
Basic Safety Message (BSM) Fundamentals
§Connected V2V safety applications are built
around the BSM, which has two parts
□BSM Part 1:
▪Contains the core data elements (vehicle size, position, speed, heading acceleration, brake
system status)
▪Transmitted approximately 10x per second
□BSM Part 2:
▪Added to part 1 depending upon events (e.g., ABS activated)
▪Contains a variable set of data elements drawn from many optional data elements (availability by
vehicle model varies)
▪Transmitted less frequently
□No on-vehicle BSM storage
of BSM data
□The BSM is transmitted
over DSRC (range ~1,000 meters)
§The BSM is tailored
for low latency, localized broadcast required by V2V safety applications