The passenger compartment of the C5 X remained stable in the frontal offset test. Dummy numbers demonstrated good protection of the knees and femurs of both the driver and passenger.  Citroën showed that a similar level of protection would be provided to occupants of different sizes and to those sitting in different positions.  Analysis of the deceleration of the impact trolley during the test, and analysis of the deformable barrier after the test, revealed that the C5 X would be a moderately benign impact partner in a frontal collision. In the full-width rigid barrier test, protection of the chest was rated as marginal both for the driver and the rear passenger, based on dummy readings of compression. In the side barrier test, protection of all critical body areas was good and the car scored maximum points.  In the more severe side pole impact, protection of the chest was rated as marginal, based on rib compression. 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 marginal. The C5 X has no counter-measure to mitigate against occupant to occupant injuries in such impacts. 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 C5 X has an advanced eCall system which alerts the emergency services in the event of a crash.   The car also has a system which applies the brakes after an impact to avoid secondary collisions.

In the frontal offset, protection was good or adequate for all critical body areas of both child dummies.  In the side barrier test, protection of all critical body areas was good for both the child 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.  All of the restraint types for which the C5 X is designed could be properly installed and accommodated.

The C5 X has an ‘active’ bonnet for pedestrian protection.  Sensors in the bumper detect when a pedestrian has been struck and actuators lift the bonnet to provide greater clearance to hard structures in the engine compartment.  Citroën showed that the system recognised a variety of pedestrian statures over a range of speeds and the car was tested with the bonnet in the raised, ‘deployed’ position.  The protection of pedestrians’ heads was almost completely good..  The bumper offered good protection or adequate to pedestrians’ legs but protection of the pelvis region was entirely poor.  The autonomous emergency braking (AEB) system of the C5 X can respond to vulnerable road users, as well as to other vehicles.  The system performed adequately in tests of its response to pedestrians and well when tested with a cyclist target, with collisions avoided or mitigated in most scenarios.

The C5 X’s autonomous emergency braking (AEB) system performed marginally in tests of its reaction to other vehicles.  A seatbelt reminder system is fitted as standard to the front and rear seats and the car is equipped with a system to detect 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 detects the local speed limit and the driver can choose to allow the maximum speed of the car to be automatically set by the system.