The number of registered vehicles in Beijing topped four million this week, state media reported, meaning a quarter of the 16 million permanent residents in China's capital have a car.
The number of qualified drivers in the city, often beset by traffic jams and air pollution, reached 5.68 million, Xinhua news agency reported late Friday, citing figures from the municipal government.
About 13.6 million people used public transport every day, up 11.1 percent from last year, according to figures from the Beijing Public Transport Group.
"Compared with other metropolises in the world, the growth of vehicles in Beijing is dramatic," Guo Jifu, researcher with the Beijing Municipal Communication Research Centre, told Xinhua this week.
It took Beijing 48 years for the number of vehicles on its streets to increase from 2,300 in 1949 to the first one million in 1997.
It took six and a half years to register the second million, Xinhua said, and the pace of growth has continued to accelerate.
Last year government vehicles and all private automobiles were banned from Beijing's roads for one day each week, depending on their licence plate number in measures aimed at easing congestion and curbing emissions.
Beijing's air is among the most polluted in the world, and the problem is getting worse amid high demand for private vehicles from its increasingly affluent residents.
China's total car sales outstripped those of the United States for the first time in January to make the Asian giant the world's biggest auto market, helped by government efforts to stimulate domestic consumption.
Explore further: Halliburton pays $1.1 bn for Gulf of Mexico BP spill