San Juan's old, cobble-stoned downtown area is fairly compact and can be explored on foot (take comfortable walking shoes) or by bicycle. In fact, many attractions have no conveniently-located parking, which can make driving downtown frustrating.The Metropolitan Bus Authority (AMA) service covers most of San Juan. Several routes, including those between Old San Juan and the tourist districts, may be useful to visitors. To go farther afield, visitors can flag down one of the plentiful taxis or minibus taxis (publicos).There is a flat-rate system for most destinations in the city, which often makes getting around by taxi quite economical but most travellers who want to explore the rest of Puerto Rico opt to hire a car, with international car rental agencies well represented.