Transport in Portugal is well-developed and diversified. Portugal has a 68,732 km (42,708 mi) network of roads, of which almost 3,000 km (1,864 mi) are part of a 44 motorways system. Brisa is the largest highway management concessionaire. With 89,015 km2, Continental Portugal has 3 international airports located near Lisbon, Porto and Faro. The national railway system service is provided by Comboios de Portugal. The major sea ports are located in Leixões, Aveiro, Figueira da Foz, Lisbon, Setúbal, Sines and Faro. Taxis offer fair value over short distances, and are plentiful in large towns and cities. Ordinary taxis are usually marked with an ‘A’ (which stands for aluguer, for hire) on the door, number plate or elsewhere. They use meters and are available on the street and at taxi ranks, or by telephone for a surcharge of €0.80.