The world's longest automated driverless train system was inaugurated in Dubai on Wednesday. The city has seen much fanfare over the past week ahead of the metro launch, with the ruler of Dubai Muhammad Al-Maktoum taking a ride on Saturday and promoting the network all week. The metro, set to open to VIPs on Wednesday and to the general public on Thursday, is part of a integrated mass transit system that aims to carry 4.5 million passengers annually by 2020. It is hoped the Metro will cut traffic congestion by 17 percent and save $1.7 billion lost each year by people being stuck in traffic jams. Initial plans for the metro were drawn up in 1992 but building did not begin until May 2005. Some 30,000 workers from five major contractors and hundreds of smaller companies have been involved in the construction, which has been reworked several times to accommodate for the sprawling growth of the city. The social networking site Twitter was rife with excitement about the launch, with comments such as "First in the Gulf", "good for the environment" and "wirhed." Many residents decided to wait until some of the excitement and crowds has died down. "Not today but perhaps on the weekend," Dubai resident Sam Gad told The Media Line. Dubai was nothing more that small fishing harbor at the bottom of a calm bay until oil was discovered in the region in the 1950s. While many of Dubai's neighbors such as Abu Dhabi came to depend almost exclusively on oil as a source of income, with its much smaller oil reserve Dubai was the first to try diversify its economy by focusing on trade and tourism. That led to a huge influx of both foreign companies and people, some for work and others as tourists. But Dubai's growth has made the city highly vulnerable to changes in the global economy, and the current global economic crisis has hit the emirate hard. In a sign of resilience, a Lebanese construction firm was announced as the master contractor for a news super tower on Monday. The building puts Dubai well on track towards becoming the city with most skyscrapers. The most famous is the Burj Dubai, which once completed will have 168 floors. It is already the tallest building in the world, having surpassed the Taipei 101 in July 2007.