Robostreet Flow: A Lightweight, Ultra-Low-Drag Electric Tractor and Four-Truck Hybrid Convoy Architecture for Minimum-Cost Point-to-Point Freight

# Robostreet Flow: A Lightweight, Ultra-Low-Drag Electric Tractor and Four-Truck Hybrid Convoy Architecture for Minimum-Cost Point-to-Point Freight
Source: [https://arxiv.org/abs/2607.26250](https://arxiv.org/abs/2607.26250)
[View PDF](https://arxiv.org/pdf/2607.26250)

> Abstract:Line\-haul trucking costs are dominated by three comparably sized components: energy, driver labor, and equipment\. Most efficiency technologies address only one component at a time\. This paper presents Robostreet Flow, a freight architecture that jointly optimizes the vehicle, convoy formation, and operating model to minimize cost per ton\-mile on high\-volume point\-to\-point corridors\. The Flow platform is a battery\-electric 6x4 tractor with a teardrop single\-seat cab and a drag coefficient of 0\.35, approximately 40% below that of conventional Class 8 tractors\. A carbon\-composite monocoque and structurally integrated batteries reduce net vehicle weight by 50%\. A 513 kWh tractor battery and a 340 kWh powered trailer battery provide a 500\-mile single\-charge range\. Four Flow trucks operate as a coordinated convoy with a safety driver only in the lead vehicle, while three followers operate in SAE Level 4 automated mode\. Computational fluid dynamics simulations show that close following at an 8 m gap reduces follower drag coefficients by 42\-48% and follower peak frontal pressure by approximately a factor of four relative to the exposed lead vehicle\. A longitudinal energy model calibrated to these results predicts fleet\-average consumption of 1\.27 kWh/mi in convoy, compared with 1\.60 kWh/mi for an isolated vehicle, for a 20\.5% energy saving\. Electricity cost is approximately 17% of the equivalent diesel fuel cost\. Amortizing one driver across four trucks and accounting for the additional payload enabled by lightweighting reduce operating cost from 9\.4 to 4\.1 cents per ton\-mile, a 56% reduction relative to a diesel baseline\. Sensitivity analysis, a hub\-to\-hub operating concept, and regulatory implications are also presented\.

## Submission history

From: Wei Wang \[[view email](https://arxiv.org/show-email/a0586529/2607.26250)\] **\[v1\]**Tue, 28 Jul 2026 20:33:08 UTC \(805 KB\)