BEIJING -- Three more urban rail sections are expected to open in Beijing this year, the city's acting mayor said in a government report Wednesday.

The total length of metropolitan rail in the Chinese capital will exceed 630 kilometers by the end of the year, Chen Jining said at the opening of the first annual session of the 15th Beijing Municipal People's Congress.

At the end of 2017, three subway lines, including one using driverless trains, started operation, bringing the total length of metro rail lines to 608 kilometers across the capital's 22 metro lines.

Beijing has been taking measures to ease traffic congestion in the city.

A total of 40 kilometers of bus lanes will be added in the city this year, with 40 bus routes being increased or optimized in operation, Chen said in the report.

Other means to bolster public transport include the renovation of bike lanes and optimization of traffic light operations based on traffic flow data, according to the report.

With more bus lanes, new subway lines and the emergence of shared bikes, traffic congestion in Beijing has eased.

According to traffic statistics, the average traffic index in the first half of 2017 was down 3.8 percent from the same period in 2016.