Dubai: The Dubai government has decided to expand the city's metro network by adding a fourth line that will serve new communities along Al Khail Road.

The Purple Line - an express line between Dubai International Airport and Jebel Ali Airport - will open by 2012 and will be in addition to the Blue Line that will run on Emirates Road and also connect the airports.

Both lines will be linked to the Red and Green lines currently under construction. "There will be a complete network of metro services ... there are plans to add more lines in future," said Abdul Majid Khaja, CEO of Dubai Metro at the Roads and Transport Authority (RTA).

The RTA will also extend tram services from Al Sufouh Road to Jumeirah Road and it will be linked to metro stations on Shaikh Zayed Road.

The total length of the Dubai metro system is estimated to be 318km by 2020, including 69.7km of the Red and Green lines. "We are expanding because we want people to leave their cars and use the metro once it is ready," said Al Khaja.