The X4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 4Runner doesn’t offer pre-crash pretensioners.
The X4 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 4Runner 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.
Over 200 people are killed each year when backed over by motor vehicles. The X4 offers an optional Active Park Distance Control that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The 4Runner doesn’t offer backup collision prevention brakes.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the X4. But it costs extra on the 4Runner.
For better protection of the passenger compartment, the X4 uses safety cell construction with a three-dimensional high-strength frame that surrounds the passenger compartment. It provides extra impact protection and a sturdy mounting location for door hardware and side impact beams. The 4Runner uses a body-on-frame design, which has no frame members above the floor of the vehicle.
Both the X4 and the 4Runner have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, plastic fuel tanks, 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.

