Get mass transit ads in over 250 cities with a single national transit advertising agency. Also defined as public or municipal transportation advertising space, transit advertisements are an excellent medium to reach the general public. Transit signs are located inside and outside of city/county and municipal public transportation vehicles/stations and terminals. (In some cities, this ad format is referred to as MTA advertising or Metro advertising.) Because of their great visibility and low transit media rates, renting public transit displays produces lots of impressions at a low CPM.