The passes must be used within 30 days of purchase and are valid from the first day of use to the last day at 2400. Major privatisation programmes have resulted in many trunk roads being upgraded. Expect tolls on motorways. Rural roads, composed of packed dirt, become impassable after rain. Nonetheless, buses are considered to be a more reliable form of long-distance transport than trains.
Traffic drives on the right.
International Driving Permit is required and this must be stamped at the offices of the Autom vil Club Argentino. Buenos Aires is generally well served by public transport. The city's underground, the subte , was the first to be constructed in Latin America. There are extensive bus services in other towns, including trolleybuses in Rosario. They are usually recognisable by their yellow roofs.