Fast, fashionable mode of transport for some, scourge of the cycle path for others: in bike-mad Amsterdam, complaints about "fatbikes" have driven authorities to impose an unprecedented ban in one of the city's top parks.
Hugely popular with children, fatbikes -- so called for their ultra-thick tires -- are electric bikes that look like squat motorcycles and can reach speeds of up to 60 kilometers (37 miles) per hour, said AFP.
Competing for space on busy cycle paths in the famously flat Netherlands, many classic cyclists see fatbikes as a menace due to their superior speed and size.
Complaints of "fatbike gangs" of youths tearing around Dutch cities and causing havoc are also commonplace.
A petition against "aggressive fatbikers" in Amsterdam has garnered 2,400 signatures, complaining: "Pavements are racetracks. Public space no longer feels safe."
So city authorities have decided to ban them in the Vondelpark, a busy park that attracts locals and hordes of tourists on hire bikes or roller skates.
"We get a huge amount of complaints," said Melanie van der Horst, the Amsterdam city official who introduced the ban.
"A few years ago, we only got around 20 complaints about fatbikes. Now we have more than 2,000," she told AFP in an interview in the park.
Aside from the nuisance value, there is a safety aspect, given the fatbikes' popularity among children, added the official.
Fatbikes are supposed to have a maximum speed of around 25 kph, but they are often illegally souped up to reach anywhere between 50 and 60 kph.
"Imagine an 11-year-old child driving around town at 50 kph on a big, souped-up fatbike. It's extremely dangerous," said van der Horst.
Children have been rushed to hospital with serious injuries after fatbike accidents, she said, including brain injuries and torn knee ligaments.
"Doctors say it is the same level of impact as a motorcycle accident."
- 'Goes very fast' -
Visitors to the Vondelpark generally welcomed the ban, with a healthy dollop of the liberal skepticism for which Amsterdam is world-famous.
"I don't think you should ban anything but I do believe that they should have started maybe by banning kids under a certain age... because I think that's the biggest issue," said Aleksandar Rankovic.
"For the park and the people who just want to have peace, I think it's a good thing," the 47-year-old football coach told AFP.
Tanja Meuris, who has recently moved into the area, also welcomed the ban, but admitted she didn't see the difference between a fatbike and a classic electric bike.
"I have an electric bike myself and I think that this thing goes very fast and it can be dangerous if not handled well," said Meuris, 27, a psychologist.
Officially introduced on May 11, the ban applies to all fatbikes with an electric motor and whose tires are more than seven centimeters (about three inches) wide.
From next week, anyone caught riding a fatbike in the Vondelpark will be hit in the wallet.
People over 16 will have to pay a fine of 115 euros ($133). Children between 12 and 15 pay half that.
Children under 12 get away without having to pay the fine, but their parents are informed.
Amsterdam authorities are keeping a close eye on the effects of the ban, which could potentially be extended to other parts of the capital.
Officials in Enschede, in the east of The Netherlands, have also taken action against fatbikes, banning them in the city center.
"We've never seen anything like this before. That's why, to protect our children, I would like to see a national law passed," said van der Horst.
"I would actually just like to get to a situation where children, especially the youngest ones, are simply not allowed to ride these bikes," she said.
