Urban AC Music is Unique ID 485 in the IAB Audience Taxonomy 1.1, in the Interest branch under Interest → Music and Audio → Adult Contemporary Music. Trillboards emits it on the bid request as a segtax=4 segment, the code every IAB-compliant DSP already reads, so a buyer already running "Urban AC Music" elsewhere can point that strategy at DOOH screens without rewriting taxonomy. Over the most recent 30-day window the network logged 1 cohort observations tagged with this segment across 24,210 approved screens.
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.
Buying one or two tiers up captures more of the network and less of the segment; buying this leaf does the reverse. The OpenRTB payload carries every level of the chain, so a single bid request can be targeted at Urban AC Music or at any node above it. Interest cohorts land hardest when the venue reinforces the interest, so pair the segment with a venue filter.