The i4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The MX-30 doesn’t offer pre-crash pretensioners.
The i4 has a standard PostCrash iBrake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The MX-30 doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
The i4 offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The MX-30 doesn’t offer all-wheel drive.
Both the i4 and the MX-30 have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, 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 BMW i4 weighs 898 to 1363 pounds more than the Mazda MX-30. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.

