The historic centre of Rome is compact and manageable on foot and most of it is closed to normal traffic. Driving in Rome is an experience to be avoided so if arriving by car it's best to park it and use public transport to get around. The network of buses, trams, metro and trains covers the whole city from 5.30am to midnight (metro to 11.30pm) and night buses take over until about 5am covering the main routes. The metro only has two lines, but is the easiest and fastest way to get around and is convenient for several attractions. The bus service is cheap and reliable, albeit slow due to traffic congestion. Tickets cover all forms of transport and must be pre-purchased and validated at the start of every journey; there are daily tickets valid for unlimited rides, or standard tickets valid for one metro ride or 75 minutes on buses. Taxis are notoriously expensive and display a list of surcharges; they are difficult to find on the streets or even at taxi stands and are best ordered by the hotel concierge or at restaurants. Note that the meter gets switched on immediately so the time it takes to arrive is added to the bill. If hailing one on the street use only the official yellow and white taxis, make sure the meter is on and have small change handy. The 110 Open is a bus service that stops at all the city's main sights, departing from Termini Station square every 20 minutes.