It is rush hour in Havana and the queue at the bus stop is longer than ever. Then a fleet of electric motorcycles appears, beeping their horns.
Surprised and relieved, passengers jump on the backs of the 50 or so electric mopeds.
It is a new solution for Cubans struggling with fuel shortages driven by US sanctions that have curbed oil imports.
Cuba has long been known for the classic American cars that people here lovingly maintain decades after they stopped being built.
But urban transport on the communist island is evolving.
The bikes' horns beep and some of the riders play reggaeton music -- but, being electric, their motors make hardly any noise.
A Chinese-made electric motorcycle costs between $1,800 and $2,300 in Cuba. A basic petrol-powered bike on the island can cost up to six times that.
- Volunteer riders -
The electric bikes -- with a maximum speed of about 50 kilometers (30 miles) per hour -- were first licensed for import in 2013.
They have multiplied in the streets since then -- and have come into their own with the recent fuel shortages.
"I really like this initiative, it helps a lot with the economy," says passenger Yanet Figueroa, 42, sitting on the back of one of the bikes.
"It really helps people who have great need of it."
Cuba plunged into a fuel crisis in September after Washington imposed restrictions on fuel shipments from Cuba's top ally Venezuela.
Cuba had to make do in September with just 30 percent of its usual fuel supply and the level has still not recovered -- it is forecast to reach no more than 80 percent this month.
With the public transport network badly hit, President Miguel Diaz-Canel has called on drivers to pick up passengers voluntarily.
The owners of electric bikes known as "motorinas" answered the call.
"We have volunteered to do this as a service to society," says one of the drivers, Javier Capote, 33.
"It is going very well. We are very happy about it."
The president himself during a televised address mentioned "those famous... what do you call them, the bikes? The 'motorinas', that have come out to help."
- Electric bike era -
Cuban authorities estimate there are 210,000 electric motorcycles currently in use on the island.
That figure is expected to rise as the government in late October began to sell them with the price capped at $1,700.
Those who make a living servicing the bikes are pleased by that move as it will bring down costs.
"It seems like a very good idea to us mechanics," says one, Enrique Alfonso, 47, in his workshop.
He recalls the economic crisis of the 1990s that followed the end of cheap imports from the Soviet Union.
"That was the era of (affordable) Chinese bicycles. Now we are in the era of electric motorcycles," he says.
"With everything that is going on the country, they have become obtainable for a lot of people."
- Accidents -
The electric bikes had a mixed reception at first. Silent and often inexpertly ridden, they are often involved in accidents in a country that already suffers from thousands of crashes a year.
Officials say that of the 7,000 road accidents recorded so far this year, a third have involved electric motorcycles.
Authorities have responded by insisting riders have a license and register their vehicles.
The flourishing of electric bikes follows several years of gradual opening-up of Cuba's state-run economy. It has also coincided with a digital mini-revolution.
Thanks to the availability of 3G-standard internet connections since last year, riders can network more easily.
The 3G connections helped spawn the Electric Motorbikes of Cuba online group, a club with more than 80 members.
It started out as a club for enthusiasts seeking to have "healthy fun and share the passion we all have for electric motorcycles and road safety," says its president Osdany Fleites, a 37-year-old taxi driver.
"The motorcycles do not pollute the environment, they do not make a noise," he says.
Now the club has evolved to have an environmental and "social purpose."
Along with another club, Eracing, its members take part in rescuing bus passengers stuck due to the fuel shortages.
They have also taken part in environmental clean-up jobs, helping eradicate an infestation of troublesome giant snails in Havana, donated blood and visited children in a cancer ward.