Tariffs are made highly visible in many places in order to keep the drivers honest. It would otherwise be easy for a driver to select the expensive out of town tariff while on a local journey in town and get paid a lot more for the journey. For example, it may be that the driver should only move to the most expensive tariff (3) when leaving the outskirts of town. If the local enforcement or police see a vehicle driving in the centre of town on tariff 3 they could then take action.
As suggested in comments there are three tariff levels in Sevilla but they apply for different sorts of journey as well as for different times. 1 is for urban, 2 for inter-urban and 3 for airport.
https://teletaxisevilla.es/tarifas/
It is in Spanish I am afraid but perhaps on-line translation tools may help here.
Credit:stackoverflow.com‘