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New performance and risk mitigation regulations for light- and heavy-duty electric vehicles

The National Highway Traffic Safety Administration (NHTSA) has proposed updated regulations that build on the current federal safety standards for electric vehicles and promote alignment between U.S. domestic regulations and Global Technical Regulations (GTRs) on EV safety. The proposed standard, , would cover light and heavy vehicles and set new performance and risk reduction requirements for EV propulsion batteries. 

The new standard would effectively replace FMVSS No. 305 — extending and enhancing many of its provisions — and create new rules for specific vehicle types and rechargeable energy storage system (REESS) safety. It would also outline the vehicle safety information provided by manufacturers to first and second responders related to EV crash or fire events and other factors. 

NHTSA has issued a request for feedback and comments to their proposed rule by June 14.

FMVSS No. 305a standards for light and heavy vehicles

Harmonized with GTR No. 20, FMVSS No. 305a expands the reach of FMVSS No. 305 to heavy vehicles (with a gross weight greater than 10,000 lb), including heavy school buses. Once published, FMVSS 305a will replace FMVSS 305. Vehicle-specific provisions of the proposed standard include:

• Light vehicles: enhanced requirements for electrical system safety during operation and post-crash, in addition to new REESS requirements
• Heavy vehicles: requirements for electrical system safety during operation and additional REESS requirements, but exempt from post-crash requirements
• Heavy school buses (with gross weight greater than 10,000 lb): enhanced requirements for electrical system safety during operation, additional REESS requirements, and post-crash requirements related to unreasonable risk of electric shock and fire

Rechargeable energy storage system mandates in FMVSS No. 305a 

Importantly, for the first time in an FMVSS standard, a portion of the proposed rule addresses safety concerns for EV REESS, including "comprehensive performance requirements and risk mitigation strategies." While these new requirements are structured to facilitate future updates as battery technologies and charging systems evolve, in the immediate future they would:

• Establish REESS protection levels regarding external fault inputs
• Ensure manufacturer-specified REESS operational thresholds
• Increase REESS and electrical system operational safety in the event of water exposure

FMVSS No. 305a safety provisions for EV crash and fire responders

Under the proposed new standard, EV manufacturers would be mandated to provide standardized emergency response safety information (guides and rescue sheets for each vehicle make, model, and model year) for first and second responders to EV crashes and fires and for this information to be made publicly available on the NHTSA website.

NHTSA public comment window and compliance timeline

NHTSA has additionally proposed a compliance date of two years after the final rule is published in the Federal Register for stakeholders to meet the new requirements. However, small-volume manufacturers, final-stage manufacturers, and alterers will be granted an additional year to comply. As with the current FMVSS No. 305, the revised standard will adopt a "self-certification" process for implementation.