To reduce the risk of injury in the result of a road accident to children travelling by cars many factors should be considered before installing a child's restraint system such as weight, height and method of installing the system. Experimental tests were carried out using child dummies (anthropomorphic test device ATD) under simulated conditions of real road conditions to understand the impact on both the dynamics and kinematics of the system involved. The dynamic tests where the likely child body's behaviour during a road accident was represented were carried out in two different versions; in the tests, anthropomorphic test device with a mass of 22 kg and 32 kg were used. The dummies were seated on booster cushions. In two tests, the likely child body's behaviour was represented for the safety belt having been correctly fastened. In another two tests, a situation was arranged that the shoulder belt part was situated behind child's back, in result of which the child's body was only restrained by the lap belt part during the accident. The results of the tests carried out with the safety belt straps being incorrectly placed have shown that the said incorrect use of safety belts may cause a greater hazard for child's safety. At the same time, for the child restraint systems to be used, the vehicle user should have elementary knowledge of the functioning of safety belts and child restraint systems.

The Rear Underrun Protective Device (RUPD) is a basic means to prevent a passenger car from running under the rear of a motor truck (also referred to as heavy goods vehicle or HGV) or a trailer in the case of a rear-end collision and thus to reduce deformations of the car’s passenger compartment (“survival space”). In many publications dealing with such devices, the increasing of RUPD stiffness by applying innovative design solutions or using high-strength materials has been considered; in some designs, additional RUPD components are introduced to absorb the impact energy. In this paper, a review of the RUPD designs is presented and some of them are analyzed, where their characteristics that are essential for the compliance with normative market requirements are indicated. Results of the authors’ research on the selection of an energy absorber incorporated in the rear impact guard bar of an HGV are presented as well.

Selected structures intended to absorb impact energy have been analysed in respect of their use in the rear underrun protective devices (RUPD) of motor trucks. The main purpose of the RUPD is to prevent a passenger car from running under the rear of a motor truck provided with such a device. From the point of view of the safety of the car occupants, it is important to take into account the components whose additional role would be to absorb a part of the impact energy so that the loads on the said occupants were minimised. This article presents experimental test results concerning selected energy-absorbing structures. Based on quasi-static strength tests, simplified material models were defined. As a result of experimental crash tests, the possible applications of selected energy absorbers to the RUPDs as their components accountable for the passive safety of passenger cars were indicated. Absorbers proposed in this paper can be considered effective energy-absorbing structures, e.g., in the case of the central impact of a medium-class car with a speed of about 40 km/h. They are relatively inexpensive in production and easily implementable to motor trucks, even taking into account some limitations related to the type-approval regulations on the European market.