The passenger compartment of the IS 300h remained stable in the frontal impact. Dummy readings indicated good protection of the knees and femurs of both the front seat occupants. Lexus showed that a similar level of protection would be provided to occupants of different sizes and to those sat in different positions. The car scored maximum points in the side barrier test, providing good protection to all parts of the body. Even in the more severe side pole test, protection of the chest was adequate and that of other body regions was good. The seat and head restraint provided good protection against whiplash injuries in the event of a rear-end collision.
Based on dummy readings and measurements in the dynamic tests, the IS 300h scored maximum points for the protection it provided to both the 18 month and 3 year infants. In the frontal impact, forward movement of the head of the 3 year dummy, sat in a forward-facing restraint, was not excessive. In the side impact, both dummies were properly contained by the protective shells of their restraints, minimising the likelihood of dangerous head contact with the car interior. The front passenger airbag can be deactivated to allow a rearward-facing child restraint to be used in that seating position. Clear information is provided to the driver regarding the status of the airbag and the system was rewarded. All categories of child restraints for which the car is designed could be safely installed in the vehicle.
The IS 300h has an 'active' bonnet which provides additional head protection for struck pedestrians. Sensors in the bumper detect when a pedestrian has been struck and actuators lift the bonnet to provide greater clearance to the hard structures underneath. Lexus showed that the system could detect pedestrians of different statures over a range of speeds. Accordingly, the car was tested with the bonnet in the deployed position and provided good or adequate levels of protection over most of the bonnet surface. The bumper and the leading edge of the bonnet also performed well, the car scoring maximum points for the protection it offered to the legs and pelvis of a struck pedestrian.
Electronic stability control is standard equipment on the IS 300h and met Euro NCAP's test requirements. A seatbelt reminder is standard for the front and rear seats. The IS 300h does not have a speed limitation device.