Medium- and Heavy-Duty Electric Vehicle Charging Infrastructure: Policy, Technology, and Deployment Considerations
The electrification of medium- and heavy-duty (MHD) vehicles—DOT vehicle classes 4 through 8— represents one of the most significant infrastructure challenges in the transition to zero-emission transportation. Unlike light-duty electric vehicles, MHD EVs introduce substantially higher power demands, more diverse duty cycles, and tighter operational constraints for fleets and drivers.
In September 2024, the Federal Highway Administration (FHWA), in coordination with the Joint Office of Energy and Transportation, issued a Request for Information (RFI) to gather input on how charging technologies, standards, and infrastructure must evolve to support this rapidly growing segment. This article synthesizes key policy and technical themes emerging from that RFI and examines their implications for infrastructure planning and deployment.
1. Unique Charging Station and Site Requirements
Physical design and layout
MHD EV charging sites must accommodate large vehicle envelopes and operational patterns. Pull-through or drive-through configurations are essential for Class 7–8 vehicles, reducing maneuvering complexity and improving throughput. Turning radii, lane widths, and overhead clearances must be designed for tractor-trailers rather than passenger cars.
Vehicle Geometry
Site geometry should support long wheelbases, trailers, and articulated vehicles without requiring backing maneuvers.
Operational Flow
Clear separation between charging lanes, staging areas, and pedestrian access improves both safety and efficiency.
Scalability
Early-stage sites should be designed for future expansion, even if initial charger counts are limited.
Power delivery and grid considerations
Power requirements for MHD EV charging range from several hundred kilowatts to megawatt-scale levels for long-haul freight applications. As a result, grid interconnection timelines and distribution system capacity are often the primary constraints on deployment.
Coordinated planning between charging developers, utilities, and public agencies is therefore critical. In some cases, on-site energy storage or managed charging strategies may be required to bridge near-term grid limitations.
2. Vehicle Charging Patterns and Operational Needs
Charging patterns for MHD EVs vary widely by vocation and duty cycle. Urban delivery trucks and buses often return to centralized depots with predictable schedules, allowing for longer dwell times and lower charging power. By contrast, regional and long-haul trucks may require rapid, high-power charging along freight corridors to minimize downtime.
Reliability and uptime
For commercial fleets, charger availability alone is not sufficient. Reliability must be defined in terms of delivered performance, including the ability to sustain rated power, complete charging sessions successfully, and maintain interoperability across vehicle platforms.
3. Charging Technology and Standardization
The emergence of the Megawatt Charging System (MCS) reflects the need for a dedicated standard capable of supporting heavy-duty applications. While multiple connector types may coexist during a transition period, long-term interoperability will be essential to reduce fragmentation and investment risk.
In parallel, cybersecurity considerations take on heightened importance at megawatt power levels, where chargers become grid-interactive assets rather than standalone devices. Alignment with established cybersecurity frameworks and secure update mechanisms will be critical.
4. Workforce, Supply Chain, and Manufacturing
Deploying MHD EV charging infrastructure at scale will require a workforce skilled in high-voltage systems, utility coordination, and heavy-equipment installation. Supply chains for power electronics, transformers, and high-capacity cable assemblies must also scale rapidly to avoid bottlenecks.
Federal and state programs that support training, domestic manufacturing, and standardized certification pathways can play a decisive role in accelerating deployment while maintaining safety and quality.
Conclusion
Medium- and heavy-duty EV charging infrastructure is a cornerstone of freight decarbonization and commercial vehicle electrification. The FHWA RFI highlights the need for solutions that are scalable, performance-driven, and aligned with real-world fleet operations.
By balancing standardization with flexibility, coordinating grid and transportation planning, and investing in workforce readiness, policymakers and industry stakeholders can enable a charging ecosystem capable of supporting the next generation of zero-emission trucks and buses.
