Revoy, a San Francisco startup, has introduced a technology that could reshape the economics and environmental impact of heavy road transport. Rather than replace entire fleets, logistics companies can retrofit existing diesel trucks with a self-powered electric trailer, converting them into hybrids without modifying the engine. The detachable, battery-powered dolly connects between the tractor and trailer, letting fleets add electric assistance while continuing to use their existing tractors.
Central to Revoy’s solution is a 3.96-meter-long, 10-tonne electric module that fits between the tractor and the basic trailer. Inside, a 575 kWh lithium-iron-phosphate battery powers an electric lead axle and provides propulsion support. When the driver accelerates, the system senses the demand and the electric motor takes on some of the load, reducing the diesel engine’s workload. During braking, the motor switches to regenerative mode, recovering energy while helping slow the vehicle.
Revoy’s system is designed for speed and flexibility. The electric trailer can be swapped out in under five minutes at dedicated stations, avoiding lengthy charging stops. By supporting existing diesel equipment instead of requiring fleets to replace tractors, the approach addresses two major barriers to heavy-truck electrification: vehicle costs and charging infrastructure. The detachable module can also serve compatible vehicles on different routes.
Safety is a basic focus. The trailer has active systems intended to prevent rollovers and jackknifing, while helping prevent loss of control. It also includes blind-spot detection and automated reverse assistance. With the module installed, a standard articulated truck with a maximum authorized weight of 36 tonnes can travel 320 to 400 kilometers on electric power alone, information from figures in the company’s product description.
Revoy says fuel consumption for a hybrid truck using the system can fall from the typical 30 to 40 liters per 100 km to as little as 6.7 to 11.8 liters, or even 5.9 liters on trips under 240 km. The company also cites potential carbon-emissions reductions of up to 85%. Separately, a Portland Business Journal summary of the company’s claims says one dolly can move an 80,000-pound truck more than 200 miles. Revoy estimates annual fuel savings of around €21,000 per truck, based on figures cited by FleetOwner.
Revoy offers the electric trailer through a subscription service rather than selling the equipment outright. The company received regulatory approval from the US National Highway Traffic Safety Administration in 2023 and completed a year-long pilot with Ryder System Inc. in 2024. Its first commercial rollout is scheduled for 2026 in Oregon, where four trailers will operate on a 320-kilometer route near Portland with second-hand diesel trucks and specially trained drivers.
The company has also announced plans to expand its engineering operations into the Portland metropolitan area after raising a $27 million Series A. Revoy said it planned to launch commercial service on the Interstate 84 corridor between Portland and Boise, a defined regional freight route suited to testing the system in regular operations. The expansion points to a staged strategy, with corridor deployment and fleet trials before any broader adoption.
The scale of the chance is impressive. Bloomberg reports that the US has roughly 3 million heavy trucks, each averaging nearly 100,000 kilometers per year. The sector is responsible for about 300 million tonnes of CO₂ annually, or 6.7% of the country’s total greenhouse-gas emissions. Retrofit systems such as Revoy’s offer one possible way to cut freight emissions while keeping existing diesel tractors in service.
For readers interested in how other manufacturers are challenging the electric vehicle status quo, a recent analysis of new approaches in the sector is available in this feature on new electric car concepts.
The technology is still in its early stages. If the Oregon pilot succeeds, similar systems could appear on highways across the US and elsewhere.
