The eHighway built by Siemens and SCAQMD is for now just a test road. It’s only one mile long, and the system only has three freight trucks that can pair with the catenary system—a battery electric truck, a natural-gas hybrid-electric truck, and a diesel-hybrid truck. The battery-electric and natural gas trucks were developed by a company called TransPower, and the diesel hybrid was developed by Volvo-owned Mack Trucks.
Each truck is able to connect to the electric wires above the highway with rooftop rods just like a trolley car (the riser on top of the trucks and trolleys is called a “pantograph”). According to a Siemens press release, “The pantograph can connect and disconnect automatically with the contact line via a sensor system while the trucks are moving. This allows the eHighway trucks to easily switch lanes or pass other vehicles without being permanently fixed to the overhead systems like a streetcar.”
Source: One way to curb freight emissions: Put trucks on an electric catenary system