Mercedes-Benz is driving three B-Class fuel-cell vehicles around the world in 125 days to show governments the technology is ready and only the lack of infrastructure is preventing the market from developing.

“The aim of the tour is to demonstrate the technical maturity and suitability for everyday use of electric vehicles with fuel cells, and at the same time highlight the need for a comprehensive hydrogen infrastructure,” Mercedes-Benz Australia says in a statement.

The cars already have crossed Europe and traveled 6,250 miles (10,000 km) in the U.S. and Canada, but to date public fueling stations only have been available at the starting point in Stuttgart, Germany, and in Los Angeles.

Precise refueling procedures were scheduled in advance to take the vehicles’ 238-mile (380-km) operating range into account. Two refueling teams are accompanying the tour to ensure a mobile fueling station is available for the cars at midday and in the evenings.

The hydrogen required is transported to each fueling point, where it is fed into the mobile fueling unit and compressed to the nominal 10,150 psi (700 bar) pressure under which it is filled into the cars.

Some 59 days after setting off from Stuttgart, the F-Cell World Drive has reached Australia, with the cars traveling from Sydney to Melbourne and then Adelaide before starting a 6-day run through the sparsely populated Outback to Perth.

From Perth, the cars will be flown to China. After spending several days at the Shanghai auto show, their route will then take them more than 8,750 miles (14,000 km) through the Eurasian continent and back to Stuttgart.

The preparations for the epic road trip began months in advance. All the routes in Europe, the U.S., Australia, China, Kazakhstan and Russia were surveyed beforehand in order to take into account local conditions and plan refueling locations.

During their 18 days in North American, the cars were able to reduce their average fuel consumption from 2.6 lbs. (1.18 kg) of hydrogen per 62 miles (100 km) achieved in Europe to 2.5 lbs. (1.15 kg).

The fuel consumption record for the U.S. was 1.9 lbs. (0.88 kg) per 62 miles, corresponding to a diesel equivalent of 78.3 mpg (3 L/100 km).

The Mercedes B-Class F-Cell vehicles will pass through 14 countries and four continents to drive around the globe once. When they return to Stuttgart, they will have covered a total of 18,750 miles (30,000 km).