The energy blockade imposed by US President Donald Trump in January has forced the country to ration gasoline to only 20 liters per vehicle through a cumbersome appointment process that can take weeks, or even months, halting public transportation. These days, the streets of Havana are almost empty of cars but teeming with thousands of bicycles and small electric motorcycles that have become the only way to get around.

"My husband owns a bicycle, so I'm riding as his companion," said Ingrid Quintana, a resident of East Havana, who works in the old part of Havana, while waiting for the tunnel bus. "It's an option we have, because there's no public transportation and we can't afford to pay for a private taxi, so we ride the Ciclobus."

The Ciclobus is the shortest public transportation route on the island, covering 3 kilometers in about 15 minutes.

After boarding near the Havana Bay Tunnel in Old Havana, passengers endure a rattling journey through the darkness of the underwater passage. They emerge in eastern Havana, a sprawling residential zone where hundreds of thousands reside. By contrast, the alternative land route must skirt the massive bay, a 16-km trek through sparsely populated and poorly paved industrial port areas.