The i5’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The ES doesn’t offer pre-crash pretensioners.
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 i5 are reminded to check the back seat if they opened the rear door before starting out. The ES doesn’t offer a back seat reminder.
The i5’s standard pretensioning seatbelts also sense rear collisions and remove slack from the front seatbelts to help protect the occupants from whiplash and other injuries. The ES doesn’t offer a whiplash protection system.
To help make backing out of a parking space safer, the i5 has standard Cross Traffic Warning with Brake Intervention, systems which detect vehicles approaching from the sides and can automatically apply the brakes to prevent a collision. Rear Cross-Traffic Braking costs extra on the ES.
Both the i5 and the ES 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, 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 BMW i5 weighs 1136 to 1557 pounds more than the Lexus ES. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.