The Toyota Mirai has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The ID.4 doesn’t offer knee airbags.
The Mirai has standard Whiplash Injury Lessening Seats (WIL), which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the WIL system moves the headrests forward to prevent neck and spine injuries. The ID.4 doesn’t offer a whiplash protection system.
The Mirai offers an optional Bird’s Eye View Monitor to allow the driver to see objects all around the vehicle on a screen. The ID.4 only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
Both the Mirai and the ID.4 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front and rear 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 and driver alert monitors.