Transit Passenger is a value of the Objects - Of Interest attribute in the Trillboards segtax=600 namespace, a signal layer for audience characteristics that IAB Audience Taxonomy 1.1 has no code for. Free-form object labels detected in the scene that are relevant to the audience interpretation. Lower-case canonical strings. Over the last 30 days the network emitted 31,276 observations carrying this value across 24,210 approved screens.
Buyers reach segtax=600 attributes one of two ways. A DSP that supports the namespace reads it straight off the bid request; the catalogue ships in the open-source @trillboards/iab-taxonomy npm package, so adding it is one dependency. A DSP that does not support the namespace can target the IAB AT 1.1 cohort layer Trillboards emits in parallel on the same observation.
Trillboards inventory concentrates in Taxi Rideshare Tv, Convenience Store, Retail Other. Taxi Rideshare Tv is the largest category at 11,909 approved screens, average floor $2.33 CPM. Those are network-wide venue counts; add a venue filter to the line item to hold delivery to the surfaces you want.
The IAB taxonomy is rich on demographics and broad interests and carries nothing for cohort composition, intent stage, or attire-driven income proxies. Trillboards produces those from the scene itself: on-device person detection and gaze tracking feed the edge layer, and a reasoning model lays structured cohort tags over the result. Objects - Of Interest is one of the headline classes in that catalogue. Every observation is aggregated at the screen-window grain behind a k-anonymity floor and carries no per-person attribute; that contract is enforced at the API and again at the data layer.