The passenger compartment of the Mercedes-Benz CLE Coupé remained stable in the frontal offset test.  Dummy readings indicated good protection of the knees and femurs of both the driver and the front seat passenger. Mercedes-Benz showed that a similar level of protection would be provided to occupants of different sizes and to those sitting in different positions.  Protection was good for all critical body areas of the front passenger.  Analysis of the deceleration of the impact trolley during the test, and analysis of the deformable barrier after the test, revealed that the Mercedes-Benz CLE Coupé would be a moderately benign impact partner in a frontal collision.  In the full-width rigid barrier test, protection was good for all critical body regions of the rear passenger and at least adequate for the driver.  In both the side barrier test and the more severe side pole impact, good protection was provided to all critical body areas and the Mercedes-Benz CLE Coupé 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 Mercedes-Benz CLE Coupé has a countermeasure to mitigate against occupant-to-occupant injuries in such impacts.  The airbag performed well in Euro NCAP’s tests with dummy readings indicating good protection for both the driver and passenger.  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.  Mercedes-Benz demonstrated that the doors would be openable to allow occupants to escape in the event of vehicle submergence.

In both the frontal offset and the side barrier tests, protection of all critical body areas was good for both the 6 and 10 year dummies, and the Mercedes-Benz CLE Coupé scored maximum points in this part of the assessment.  The Mercedes-Benz CLE Coupé senses when a child restraint has been put in the front passenger seat and automatically disables the airbag.  The system works robustly for various occupant and restraint system types, and was rewarded.  The Mercedes-Benz CLE Coupé 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.  Indirect systems are no longer rewarded by Euro NCAP. All of the child restraint types for which the Mercedes-Benz CLE Coupé is designed could be properly installed and accommodated in the car.

The Mercedes-Benz CLE Coupé has an 'active' bonnet.  Sensors in the bumper detect when a pedestrian has been struck and actuators lift the bonnet surface to provide more space to the hard structures underneath.  Mercedes-Benz showed that the system worked robustly over a range of speeds and for different statures.  Accordingly, the car was tested with the bonnet in the raised, deployed position.  Protection of the head of a struck pedestrian or cyclist was largely good or adequate, with poor results recorded only on the stiff windscreen pillars and at the base of the screen.  Protection of the pelvis, the femur and the knee and tibia was good at all test locations, and the CLE Coupé scored maximum points in these areas of the assessment.  The autonomous emergency braking system of the Mercedes-Benz CLE Coupé responds to vulnerable road users such as pedestrians and cyclists, as well as to other vehicles.  In tests of its response to pedestrians the system performed well, including protection for those to the rear of the car.  The system also performed well in tests of its reaction to cyclists.  A system to protect against ‘dooring’, where a door is opened into the path of a cyclist approaching from behind, is available as an option and is not included in this assessment.  The system’s response to motorcyclists was good.

Overall, the performance of the autonomous emergency braking (AEB) system was good in tests of its reaction to other vehicles.  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 and some types of distraction.  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.