Driving in Rio is not recommended for overseas visitors due to the chaotic nature of the traffic. But driving is usually not necessary as the public transport system in Rio is cheap and efficient, and most places can be reached by metro or bus. By far the quickest and easiest way to get around is by the efficient metro, but with only two lines, there are limits to its coverage. Walking around is generally safe as long as there are crowds of people, although walking in the centre of the city is not recommended after the shops close and their security guards go home.The most inexpensive form of transport is the local buses, which travel all over the city as fast as the traffic will allow. Buses are privately operated, so services and costs will vary. Unfortunately, they are often badly driven, crowded, and the scene of petty theft. Special care should be taken on buses known to be used by tourists, such as those to the Sugarloaf.Most public transport stops around midnight, with some buses operating twenty-four hours, but it is safer to hire a taxi late at night. Radio taxis can be ordered and are said to be safer and more reliable, usually with air-conditioning, but they are more expensive than regular taxis. Drivers may add a surcharge for extra luggage. Most taxi drivers speak only Portuguese, so visitors should have their destination written down.