The A6 e-tron’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Mirai doesn’t offer pre-crash pretensioners.
Both the A6 e-tron and Mirai have child safety locks to prevent children from opening the rear doors. The A6 e-tron has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The Mirai’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.
In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the A6 e-tron are reminded to check the back seat when a sensor determines the back seat is occupied. The Mirai doesn’t offer a back seat reminder.
The A6 e-tron Quattro has all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Mirai doesn’t offer all-wheel drive.
Earlier warning of stopped traffic, traffic signals, dangerous road conditions, weather, or accidents, can keep driver's safer and prevent crashes. The A6 e-tron has Car-to-X Services, a system that seamlessly communicates important warnings to the driver about impending danger, if they're available. The Mirai doesn’t offer a system that can receive automated systems from infrastructure or other vehicles.
Both the A6 e-tron and the Mirai have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning, driver alert monitors and available around view monitors.
The Audi A6 e-tron weighs 694 to 937 pounds more than the Toyota Mirai. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.