Dockless bicycles in China have reduced inner-city car trips by more than 7 percent in some areas, easing gridlock and fighting smog, according to studies, the Canadian Broadcasting Corp. reported.

These bicycles have also cut total car trips by 3.8 percent in some cities, the CBC reported, citing mapping industry studies. Also, according to a Chinese technology institute, on a single day last year, 70 million people rode dockless bicycles in China, the CBC said.

While the bicycles appear to have made a rapid impact on air pollution and gridlock, they also have created pollution of another kind as users dumped them wherever they pleased. In some Chinese cities, officials have had to use bulldozers to clear them away.

Earlier this year, Washington, D.C., announced plans to expand dockless bikes and scooters while also imposing new rules to protect riders and pedestrians and prevent streets from becoming dumping grounds — an approach hailed by those who see them as a scourge and criticized by those who see them as a smart form of urban travel.

In China, the GPS-managed bike-sharing system, introduced last year, has proved to be much more popular than earlier systems that relied on docking stations, the CBC reported. The CBC article cited research by the China Institute of Information and Communications Technology (CIICT), which said that some dockless bicycles are used three to four times a day. CIICT credits the system for reducing carbon dioxide emissions last year to a number equivalent to taking more than 900,000 cars off the road that would have been contributing to China’s notoriously heavy air pollution.

“For years, we thought the way to cut traffic congestion in Beijing was to build more roads and parking lots,” Zhao Yixin, a planner with the Urban Transportation Institute who advises the city government, was quoted as saying. “We learned that doesn’t work. There’s always more cars and more traffic. But these bicycles are actually having an impact.”

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