BEIJING, Aug. 13 (Xinhua) -- Beijing will continue to improve its public transport service by expanding transport networks while keeping fares low, a Beijing official said on Wednesday.

　　These measures are expected to encourage more Beijing residents to use public transport, which can help reduce road congestion and car emissions, said Zhou Zhengyu, deputy director of the Beijing Municipal Committee of Communications.

　　Beijing plans to build 11 more subway lines to create an underground transport network of 561 kilometers by 2015, compared with eight lines of 200 km at present, Zhou said.

　　"Meanwhile, the proportion of the usage of public transport will be raised to 45 percent from 35 percent at present. That's our major goal," Zhou said at a media briefing on the city's transport system during the ongoing Olympic Games.

　　Beijing has actually achieved this goal since the opening of the Games on Aug. 8, thanks to policies that encouraged the use of public transport, he said.

　　The government ordered about two-thirds of Beijing's 3.3 million cars off the roads on alternate days under an even-odd license plate system that is in effect from July 20 to Sept. 20, during the Olympics and the following Paralympics.

　　Many government cars have also been taken out of service. However, more buses, taxis and Olympic vehicles were put on the roads.

　　Zhou said the measures, although they inconvenienced many commuters who rely on private cars, paid off as more citizens opted for mass transit.

　　He said after the policy took effect on July 20, between 1.8 million and 2 million cars were kept off the roads daily, reducing emissions by at least 20 percent.

　　"As we can feel these days, air quality has improved and the roads are less congested," he said.

　　Zhou said although the odd-even license plate system was a temporary policy, decision makers and the general public weren't likely to ignore its obvious benefits.

　　The official also said that the low-fare policy would continue to get more people into public transport.

　　The subway fare was slashed from 3 yuan (0.44 U.S. dollars) to 2 yuan per trip, while bus fares were as low as 0.4 yuan.

　　Beijing has mobilized more than 22,000 buses while keeping the subway running late to cope with a surge in passengers since the Olympics opened on Aug. 8.

　　The subway system handled a record 4.1 million passengers on Tuesday, Zhou said.

　　He admitted that transport in Beijing, with a population of 17 million, has been under "tremendous" pressure due to population growth, rapid urbanization and the fast increase in private car ownership.

　　"The solution to these challenges must be continuous development of public transport," he said.