C. Braking test:


D.Open road test:


In general terms, it could be concluded that when the ChC is unrestrained and moving freely without the wheel brakes applied, it moves inside the bus, hitting the different parts of the passenger compartment (**Figure 7C**). In these tests it was found that if the ChC is not restrained by an adult or any other system, in the event of normal or emergency movement maneuvers of the vehicle, it tends to slip and hit the bus interiors, regardless of its orientation, even if the wheel brakes are applied (**Figure 7A** and **7B**). When wheel brakes are not applied, the ChC moves but has less tendency to overturn, and the resulting acceleration is somewhat lower.

Many of the ChCs in the current market have a tendency toward lateral overturning that can be easily achieved for vehicle maneuvers with accelerations of less than 5 m/s<sup>2</sup> (*0.5 g*) [12]. When the ChC hits the vehicle's interior without a direct impact of the child, the acceleration of the dummy's head and chest can be up to 10–20% of the ChC deceleration. In case of lateral overturn, in some models of

*Passive Safety of Children Carriages on Busses DOI: http://dx.doi.org/10.5772/intechopen.90613*

#### **Figure 7.**

*Examples of the dynamic behavior of the ChC unfolded during the closed-track tests developed in the ASUCAR project (source: [20]). (A) Circular test: wheel brakes applied. (B) Slalom test: wheel brakes applied. (C) Braking test: wheels spinning freely.*

ChC, the child could suffer an impact onto the head when hitting against other parts of the body. In these cases, the deceleration could generate a high risk of damage to the child head.

It was possible to verify that with ChC unrestrained, the safer position for traveling is to place it longitudinally in a rearward-facing direction, resting on the backrest installed in the area reserved for a wheelchair user, as recommended by the UNECE Regulation R107 [11]. However, this position could also be dangerous when the ChC is not restrained in any way to the backrest (as it is a passive safety

**Figure 8**.

*Most adequate position of unfolded ChC for traveling in M3 vehicles: (A) with space occupied by ChC; (B) with space unoccupied by ChC (source: [14]).*

system), so it can rotate and be launched toward the corridor with a relatively high deceleration (*2.5 g*) and jump to the front of the vehicle (*6.5 g*) during an emergency braking. In these cases, the ChC should be held by a restraint system such as the one shown in **Figure 8**, with a safety lap belt. The only drawback of this traveling position is that in case of an emergency braking or a frontal impact, the passengers of the bus, or other ChCs located in front of it, could be thrown against the carriage, causing physical damage to the child or baby. Finally, it should be noted that, for all tests, the transversal position of the carriage to the direction of travel is inadvisable.
