The four main islands and all the towns and villages are linked by well-constructed roads. There were of roadways in 2002, of which were paved. A causeway stretching over , connect Manama with Muharraq Island, and another bridge joins Sitra to the main island. A four-lane highway atop a causeway, linking Bahrain with the Saudi Arabian mainland via the island of Umm an-Nasan was completed in December 1986, and financed by Saudi Arabia. In 2000, there were 172,684 passenger vehicles and 41,820 commercial vehicles.