In 2016, Sweden debuted the world’s first “electric highway.” Basically, it’s a stretch of highway that has a series of wires hanging overhead that a cargo truck equipped with a pantograph can connect to. When the truck connects to it, the vehicle can deactivate its fuel-burning engine and coast along on that delicious, dirt-cheap electricity, switching back when the wires stop.

The electric highway has been out of the news for the last couple years, but now it’s making a return as Germany has started real-world tests of an eHighway system on a 3.1-mile stretch of the Autobahn between Frankfurt and Darmstadt, with an electric-diesel hybrid truck merging into everyday traffic while it received power from the overhead cables.

The system won’t have a major impact for a while. Just five trucks will run the electrified stretch each day where roughly 10 percent of the road’s 135,000 daily vehicles are heavy trucks. That reduced emissions footprint could scale up as more trucks support the system, though, and could encourage trucking companies to go electric knowing that their cargo haulers could drive longer on a charge.