I first thought, “Impossible”, but no.
Quote: “The SPEED-VEST is a bicycle safety device and advocacy tool which displays the wearer’s current speed on their back in easy-to-read lighted numerals. It improves rider conspicuity while legitimizing bicycle speeds on the roadway. Originally conceived by Brady Clark and engineered by Mykle Hansen.”
Advocacy tool? Conspicuity? But combined with tiny cameras and flash drives, an entire traffic ‘event’ can be recorded.