Commuters in central Barcelona have had the opportunity to ride a bus free of charge this week—but with one notable difference: there’s no driver behind the wheel.

The autonomous mini-bus starts and stops on its own, braking when changing lanes and smoothly cruising down one of the city’s most popular boulevards.

Renault is conducting tests of its new driverless mini-bus in Barcelona, operating it on a 2.2-km (1.3-mile) circular route with four stops in the city center. Adventurous passengers can ride the bus for free during the trial.

The French automaker has partnered with WeRide, an autonomous vehicle company, to develop the prototype. After unveiling it at the French Open last year, Renault is now testing the vehicle on public roads in Barcelona. Additional tests are taking place in Valence, France, and at Zurich airport.

Pau Cugat, a curious 18-year-old student, took a short ride along Passeig de Gracia and compared the futuristic bus to a traditional city bus. “We just passed by a regular combustion-engine bus, and I thought, ‘Look, there is a bus of the past, and right behind it you have the bus of the future,’” he said.

Driverless vehicles, including taxis and buses, are being tested in cities like San Francisco and Tokyo, but Europe has generally lagged behind the U.S. and China in autonomous vehicle development, where companies are aggressively competing.

“The US and China are doing a lot of experimentation with autonomous vehicles,” said Patrick Vergelas, head of Renault’s autonomous mobility projects. “Until now, Europe hasn’t seen much of this, and that’s why we want to demonstrate that this technology works and prepare Europe for this type of public transportation.”

The electric bus can travel up to 120 kilometers on a single charge and reach speeds of 40 km/h (25 mph). It’s equipped with 10 cameras and eight lidar sensors to navigate through the busy streets of Barcelona, filled with cars, motorcycles, and pedestrians. According to Renault, the bus can operate safely in such a high-traffic environment.

Carlos Santos from Renault’s autonomous driving team noted the range of reactions from passengers. “We’ve seen people smiling, others taking photos, and some even trying to open the doors,” he said. Despite the mixed reactions, he assured that the ride was safe.

City officials in Barcelona reported no accidents involving the experimental bus.