"The way a hybrid model earns the top rating in the frontal test is the same way any other car does. Its front structure has to crush to absorb crash energy, and it has to have a safety cage that stays intact so the safety belts and airbags can protect the occupants." says the Insurance Institute for Highway Safety's President Adrian Lund.
Additionally, they must meet FMVSS 305, Electric Powered Vehicles: electrolyte spillage and electric shock protection. This standard specifies limits for electrolyte spillage, battery retention, and post-crash electrical isolation of the chassis from the high voltage system in vehicles that use electricity as propulsion power.
In contrast to standard vehicles, which use the chassis as part of the 12-volt electrical circuit, hybrid-electric vehicles use heavily insulated wires for both the positive and return sides of the high voltage circuit. Automatic shutoff systems reduce the potential for post-crash electrical shock from the high voltage system.