Robostreet Flow cuts freight cost 56% with electric convoy of four trucks
A single driver pilots four electric trucks, slashing cost to 4.1 cents per ton-mile
Robostreet Flow, a new freight architecture from a research team led by Wei Wang, combines a purpose-built electric tractor with a four-truck hybrid convoy to tackle the three biggest line-haul costs: energy, driver labor, and equipment. The Flow platform features a teardrop single-seat cab with a drag coefficient of just 0.35 (40% lower than standard Class 8 trucks), a carbon-composite monocoque that cuts net vehicle weight by 50%, and a total battery capacity of 513 kWh on the tractor plus 340 kWh in a powered trailer—good for a 500-mile single-charge range.
In operation, four Flow trucks form a coordinated convoy with a safety driver only in the lead vehicle, while the three followers operate in SAE Level 4 automated mode. Computational fluid dynamics simulations show that following at an 8-meter gap reduces follower drag coefficients by 42-48% and peak frontal pressure by roughly fourfold. A calibrated longitudinal energy model predicts fleet-average consumption of 1.27 kWh/mi in convoy, compared with 1.60 kWh/mi for an isolated Flow vehicle—a 20.5% energy saving. Electricity costs are about 17% of equivalent diesel fuel costs. By amortizing one driver across four trucks and adding payload from lighter components, the team projects operating cost drops from 9.4 to 4.1 cents per ton-mile, a 56% reduction versus a diesel baseline. The paper also discusses hub-to-hub operations, sensitivity analysis, and regulatory implications for deploying such autonomous convoys.
- Electric tractor with 0.35 drag coefficient (40% lower than conventional Class 8 trucks) and 50% lighter carbon-composite body
- Four-truck convoy with 8m gap: followers achieve 42-48% drag reduction and operate at SAE Level 4 autonomy
- Operating cost drops 56% from 9.4 to 4.1 cents per ton-mile by combining lightweighting, one driver for four trucks, and low electricity costs
Why It Matters
This architecture could fundamentally reshape long-haul trucking economics, cutting per-mile costs by more than half while reducing energy use and driver dependency.