The passenger compartment of the Lexus LBX remained stable in the frontal offset test.  Dummy readings indicated good protection of the knees and femurs of both the driver and passenger.  Structures in the dashboard were thought to pose a risk of injury to occupants of different sizes and to those sitting in different positions, and the score for this part of the body was penalised.  Protection of the driver’s chest was also rated as marginal, based on dummy readings of chest compression.  Analysis of the deceleration of the impact trolley during the test, and analysis of the deformable barrier after the test, revealed that the Lexus LBX would be a benign impact partner in a frontal collision. In the full-width rigid barrier test, protection of the head of the rear passenger dummy was rated as marginal, based on the extent to which the head travelled forward in the impact. However, in both the side barrier test and the more severe side pole impact, protection of all critical body regions was good, and the LBX scored maximum points in this part of the assessment. Control of excursion (the extent to which a body is thrown to the other side of the vehicle when it is hit from the far side) was found to be adequate. The Lexus LBX has a countermeasure to mitigate against occupant-to-occupant injuries in such impacts.  The performance of this countermeasure was not assessed, as it was considered to interfere with the results of the near-side pole test.  As a result, the score was penalised.  Tests on the front seats and head restraints demonstrated good protection against whiplash injuries in the event of a rear-end collision.  A geometric analysis of the rear seats also indicated good whiplash protection.   The car has an advanced eCall system which alerts the emergency services in the event of a crash, and a system to prevent secondary impacts after the car has been in a collision.  Lexus demonstrated that the doors and windows would be openable to allow occupants to escape in the event of vehicle submergence.

In both the frontal offset test and the side barrier impact, protection of all critical parts of the body was good or adequate for the 6 and 10 year dummies. The front passenger airbag can be disabled 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. The LBX is equipped with an indirect 'child presence detection' system, which issues a warning when it recognises that a child or infant may have been left in the car. All of the child restraint types for which the Lexus LBX is designed could be properly installed and accommodated in the car, apart from two belt-mounted restraints in the rear centre seat.

Protection of the head of a struck pedestrian or cyclist was predominantly good or adequate, with a few poor results recorded only on the stiff windscreen pillars.  Protection of the pelvis was good at all test locations.  Protection of the pelvis was not poor at any test point, and that of the femur was mixed.  Protection of the knee and tibia was good at all test locations.  The autonomous emergency braking (AEB) system of the Lexus can respond to vulnerable road users as well as to other vehicles.  The system’s response to pedestrians was good.  A system to protect pedestrians to the rear of the car is available as an option but was not included as part of this assessment. The system’s performance in tests of its reaction to cyclists was also good, but protection against ‘dooring’, where a door is suddenly opened in the path of a cyclist approaching from behind, is optional and not assessed here.  Performance of the AEB system was good in tests of its response to motorcyclists.

Overall, the performance of the autonomous emergency braking (AEB) system was good in tests of its reaction to other vehicles, with impacts being avoided in most tests.  A seatbelt reminder system is fitted as standard to the front and rear seats.  The car has an indirect driver status monitoring system as standard, detecting driver fatigue.  The lane support system gently corrects the vehicle’s path if it is drifting out of lane and also intervenes in some more critical situations.  The speed assistance system identifies the local speed limit.  The driver can choose to allow the limiter to be set automatically by the system.