Mass transit is growing increasingly popular in Colombia. Bogotá boasts the TransMilenio, and Cali and Bucaramanga have similar projects, called the Mio and Metrolínea, respectively. Medellín has its famous Metro, the only commuter rail line in the country. Pereira, too, offers the MegaBús system. Taxis are cheap, convenient and ubiquitous in the major cities and most mid sized towns. In most big and medium-sized cities taxis have meters but in some parts of the Caribbean coast and in smaller towns prices are fixed according to the destination. While in theory these prices should be listed on a card hung from the passenger seat, this is in reality often missing, in which case you should agree a price before getting in.Almost every urban center of more than 100,000 inhabitants has a bus service, as do many smaller towns. The standard, speed and efficiency of local buses vary from place to place, but on the whole they are slow and crowded. City buses have a flat fare, so the distance of the ride makes no difference. You get on by the front door and pay the driver or the assistant. You never get a ticket.