The NHTSA has proposed updating its regulations to help support hydrogen fuel cell and mild hybrid vehicle development.
The regulations of most importance is a provision to protect high-voltage sources via "physical barriers," to prevent electrical shock and injuries to occupants or first responders in an accident. EVs currently have an electrical disconnect system that breaks the conductive link to the battery in an accident.
Toyota and the Alliance of Automobile manufacturers submitted a petition arguing that the regulations should not require a mechanical disconnect system to activate in low-speed accidents, as vehicles can be effectively disabled due to minor 'fender benders.' Furthermore the Alliance claimed that the NHTSA's high-voltage definition should be readjusted to 48-volts from its current definition of 30 volts. This is to remove a development barrier for the industry as modern 48-volt systems are needed to run electric compressors and other innovative technologies.
http://www.leftlanenews.com/nhtsa-proposal-aims-to-push-fuel-cell-technology-91159.html"Since these systems are grounded to the vehicle chassis, they cannot meet FMVSS No. 305's existing electrical isolation option," the automakers said. "While it is feasible to design a 48 volt mild hybrid system that is isolated from the chassis and meets FMVSS No. 305's electrical isolation requirements, such designs involve more complexity, higher consumer costs, and higher mass resulting in reduced fuel economy and increased emissions."
The NHTSA believes its relaxed rules will allow mild hybrid technology and hydrogen fuel cells to be used in a wider range of vehicles, simplifying development work and aligning US laws with global standards.