BEIJING - Beijing is scheduled to put four subway lines into operation on Sunday, part of the city's efforts to expand rail transit to ease severe traffic congestion.

The newly-opened lines include the new No. 6 Line, the southern section of the current No. 8 Line, the northern section of the current No. 9 Line and the southern and western stretches that complete a loop for the current No. 10 Line.

The new lines bring the number of subway lines in Beijing to 16, with a total length of 442 kilometers, the Beijing Municipal Commission of Transport said in a statement on Saturday.

The city has turned to public transport, especially rail transit lines, to tackle massive traffic jams on the city's vehicle-clogged roads.

The number of subway lines in Beijing will reach 19 by 2015, with a combined length of 561 km. By 2020, the total subway length is expected to increase to 1,000 km.

Beijing's public transportation system, including bus services, carried an average of 20.6 million people per day in 2012. About 44 percent of Beijing residents say they use public transport, the highest percentage of all cities nationwide.

Amid other measures to ease traffic, city authorities started limiting new vehicle registrations to 240,000 each year in 2011, slashing new car registrations by two-thirds from the 2010 level.

Vehicles are also banned from roads one day per week according to plate numbers.