Paris (AFP) - Emerging from the tunnel of a former highway along the River Seine in Paris, bikes zip past the cars caught in traffic on a road just next to them.
"It's great for cyclists, it's safer," says Kolestin Onaindia, though he is one of just a handful of riders taking advantage of the car-free thoroughfare on a weekday afternoon.
Onaindia knows his perk comes with a price.
Before he retired, driving to work along the same stretch of the riverbank near the Louvre museum was a quick 25-minute commute. Now he says the same drive would take twice as long.
"For people who come and have to get across Paris, it's a catastrophe," he says.
At least Onaindia had his own wheels.
Tens of thousands of Parisians who use the city's popular Velib bicycle-hire service have been forced off the roads since January by a shambolic rollout of new bikes that is not expected to be completed until this summer.
Bike-sharing and car-free riverbanks were supposed to be flagships of Mayor Anne Hidalgo's pledge to tackle smog in the French capital, which can get so bad that children's football matches are cancelled.
She says her policies, first implemented while she was deputy mayor, have cut car traffic in Europe's most densely populated city by 30 percent in the past 10 years.
And she wants to go further, imposing stricter pollution rules with the goal of phasing out diesel vehicles by 2024, when Paris is set to host the Summer Olympic Games, and gasoline-powered cars by 2030.
But the Velib fiasco and simmering resentment among drivers have turned up the pressure on the mayor, who now appears increasingly vulnerable to a 2020 election challenge despite her Socialist party's nearly 20-year grip on the city.
- 'Misguided ecological utopia' -
Hidalgo was dealt a setback last month when a court overruled the riverside road closures she imposed in 2016.
The court accused her office of "inaccuracies" and "omissions" -- or as her critics put it, false claims on supposed pollution benefits.
A regional air pollution monitor recently gave a "mixed" review of the "pedestrianisation" of the 3.3 kilometres (two miles) of highway, saying the benefits were offset by increased congestion and higher emissions elsewhere in Paris.
And the move infuriated the roughly five million drivers who commute to Paris, who scoffed at Hidalgo's claims that road closures would encourage them to use public transport -- an impractical option for many living in the suburbs.
A committee set up to evaluate the plan's effects found in November that there had been no meaningful decline in traffic, while jams on nearby routes had increased rush-hour travel times by up to 70 percent.
"The reality is that 30 more minutes are being lost during rush hour," said Pierre Chasseray of the 40 Million Drivers advocacy group, which has denounced Hidalgo's "misguided ecological utopia".
Hidalgo rushed out another decree after the court ruling to keep the riverside roads closed, citing a poll which found 55 percent of Parisians in favour of the measure.
But Chasseray's group is preparing a fresh legal challenge along with business associations.
- #Velibgate -
Hidalgo's other big headache is the overhaul of Velib, hailed as a model for major cities when it was rolled out 10 years ago, but which has basically been out of service since the start of the year.
Critics say her administration made a huge miscalculation by thinking a system handling some 20,000 bikes for an estimated 300,000 users could be ripped out and replaced in just a few months.
According to the Paris En Selle (Paris in the Saddle) association, just 80 of the promised 1,450 new stations are reliably working since the system's new operator took over, because they are the only ones hooked up to the city's electrical grid.
A few hundred more work in theory, but are being temporarily powered by batteries prone to failure -- so even if the Velib app says a station is available, users often find it's impossible to take a bike.
"If you have to take a gamble on whether or not the system is working, then it's clearly not working," said Paris En Selle spokesman Simon Labouret.
City hall has had to deploy its own engineers to help install the new stations for Smovengo, an upstart operator whose previous bike-sharing programmes were limited to much smaller schemes in cities like Vancouver or Moscow.
Smovengo, which has been fined three million euros ($3.7 billion) over the delays, has for its part lashed out at city officials for "serious shortcomings" in managing the handover.
For riders, higher prices for the service are salt in the wound over what has been dubbed #Velibgate on Twitter.
"We're waiting for serious action to get out of this mess, to restore a public service that is absolutely essential for Paris," Labouret said.