China's two biggest cities have banned the use of electric scooters and segways on public roads because of safety concerns.
Beijing and Shanghai traffic authorities this week started issuing verbal warnings and fines of 10 yuan ($1.50; £1.1).
Modified bicycles, scooters and segways have been growing in popularity in China as a way to beat traffic jams.
However, many do not have proper brakes or lights, and can exceed speed limits.
Electric scooters and segways are supposed to have a maximum speed of 20km/h, but the Beijing Consumers' Association found that most of them are able to exceed that.
China's third-largest city Guangzhou is also reportedly considering a ban on electric scooters.
There are no national safety standards for such vehicles, which do not fall in the category of either motor vehicles or non-motorised ones according to Chinese law.
Analysis: Stephen McDonell, China correspondent
Though the ban on stand-up electric scooters is now in place in Beijing and Shanghai, you can still see plenty of them on the streets.
There are only three possibilities: people are not yet aware of the new rule changes, some have decided to risk being busted or riders will simply pay the small fine if they get caught.
If you talk to the mostly young people who own and love these scooters, they say they're cheap, convenient and easy to recharge. They also say that the problem instead lies with the sea of cars clogging up China's major cities every day.
The government response is that this may be the case, but it doesn't make the scooters any safer.
People - using all manner of vehicles - can been seen doing crazy, dangerous things every day on China's roads, so when cool kids were seen standing up on their electric scooters and whizzing through traffic, nobody thought it was in the slightest bit strange.
Transport officials didn't see it this way.
To them, these scooters move way too quickly and brake way too slowly.