The transportation system in Malta is small but extensive, and the islands' domestic system of public transportation is reliant on buses and taxis, although there were both a railway and a tramway in the past. Traffic in Malta drives on the left, as in the UK. Car ownership in Malta is exceedingly high given the very small size of the islands. The country has the fifth-highest number of vehicles per capita in the world as of 2009, with 607 motor vehicles per 1,000 people. The number of registered cars in 1990 amounted to 182,254, giving an automobile density of 582 per km². Buses are the primary method of public transportation for the Maltese Islands and have been in operation there since 1905, offering a cheap and frequent service to many parts of Malta and Gozo. The vast majority of buses on Malta depart from a terminus in Valletta. Malta's buses carried over 40 million passengers in 2015.