In what the developer says is a world first, arms fitted underneath electric trucks, buses and light vehicles automatically connect with the rail when they drive above it.

When they move away from the rail – turning off the road or during overtaking manoeuvres, for instance – the arms automatically retract.

The rail is connected to the electricity grid and divided into sections that are only powered when vehicles move over them.

The system's able to calculate the electricity being used by each vehicle drawing power from the rail – so costs can be charged to the users.

Developer eRoadArlanda says that a beauty of the system is that the rails can be embedded in existing roads.

For the trial, a two-kilometre stretch of public road between the Arlanda Cargo Terminal and the Rosersberg logistics area outside Stockholm has been electrified – to be used by trucks converted to use the system as part of the project.

eRoadArlanda is already planning to electrify more roads around Sweden…and globally.

"One of the most important issues of our time is the question of how to make fossil-free road transportation a reality," says Hans Säll, eRoadArlanta chairman.

"We now have a solution that will make this possible, which is amazing."

The developers say that only major routes – around 3% of Sweden's total road network – would need to be modified to make a considerable cut in carbon emissions. Shorter journeys between the electrified major routes would be undertaken using vehicles' stored battery power.

Swedish PM Stefan Löfven announced three years ago that the country intends becoming "one of the first fossil fuel-free welfare states in the world."

The target is to make the country's transport infrastructure completely fossil fuel-free by 2030. Currently road transport accounts for a third of Sweden's carbon emissions.