Rides
Ridership and Unlinked Trips refer to the amount of rides passengers on The Rapid take over the specified time period (weekdays, weekends, monthly, annually). "Rides" as opposed to "passengers" are the industry standard measures for ridership because one passenger could take multiple rides in any given time period. For instance, one passenger riding on a certain route and then transferring to another is counted as two "unlinked trips."
Annual Passenger Miles refers to the total amount of miles traveled on every "ride" or "unlinked trip."