The most affordable way to get around Fortaleza is by bus. Travellers can get off at a terminal and change lines without paying again, provided they do so within a certain time period. Most lines run seven days a week and depart every 10 minutes, or 20 minutes at night and on weekends.Over 4,000 taxis run on the same meter system (excluding the special cabs at the airport). Taxis have standardised rates, with increased fares at night, on weekends and over December. Taxis are obligated to display the fare system on one of the rear side windows. Travellers should avoid cabs that don't. Chaotic traffic makes driving difficult in Fortaleza, but rental car outlets are available in town and at the airport.