**Abstract**

The safe mobility of young children traveling with carriages in public transportation vehicles is a problem that has not yet been satisfactorily resolved. The lack of national and international standards in this area in the past led to the development of a research developed jointly by the Universitat Politécnica Valencia and the Universidad Politécnica Madrid (Spain). This book chapter shows the results of a research program developed to evaluate the dynamic behavior of occupied children carriages (ChC) during typical driving maneuvering—sudden braking, acceleration and cornering—and in case of low-g accidents reproducing frontal impacts resembling real traffic events (deceleration 2 g, ΔV 20 km/h). In the dynamic trials, three ChC-restraint prototypes and a typical wheelchair (WhCh) back-restraint system combined with two representatives of up-to-date ChC models in misuse and correct use configurations were tested. The results demonstrated the need for preventing children injuries as a consequence of low-g accidents.A Code of Good Practice was proposed jointly with the use of a new ChC-restraint system considering R 107–06 series of amendments. The new design improves the latest revision of regulation R107 regarding the use of back-restraint systems for the transport of WhCh and ChC passengers traveling on busses.

**Keywords:** transportation safety, children carriages, children injury, restraint system, public transport

### **1. Introduction**

The proper use of public transport systems is currently a vital need that must be pursued by public administrations to maintain quality standards that facilitate the adequate mobility of the majority of the population. These minimum standards should include both accessibility, comfort, and safety when traveling, so that their use can be extended to groups with disabilities or reduced mobility. Among these groups, we must not only include people with physical disabilities but also those who suffer from cognitive or sensory disabilities—auditory or visual. In the same way, accessibility and safety problems were important for passengers traveling in road transport vehicles without leaving their wheelchairs; there are actually passenger groups that experience similar difficulties at the time of using bus transport systems. This is the case of passengers traveling accompanied by children's carriages.

There are not many statistical studies that analyze the accident rate related to the transport of children's carriages (ChC) on busses, but their behavior, from the

transport safety perspective, is very close to that suffered by passengers traveling without leaving their wheelchair (WhCh). In this sense, the scientific community has introduced the term *incident* in accident studies, more in line with the interaction of the passenger—with/without reduced mobility—with the transport vehicle environment, considering the source of the accident, not only the vehicle's own impact but also other causes such as the boarding-disembarking action, the use/misuse of restraint systems, or the vehicle's critical or emergency maneuvers.

Most studies related with the concurrence of *incidents* in bus transport have shown that these occurred without impacts and in most cases in urban areas [1, 2]. Some studies have concluded that the injuries produced during these incidents were due to sudden changes in speed (60% in braking and 25% in acceleration) [3] or when the vehicle is stopped, during the boarding/disembarking phases [4], affecting the elderly and the disabled to a greater extent. Most of the damage suffered occurs as a combination of a WhCh overturning and the occupant's fall, followed by incidents without falls and situations in which the occupant falls from the WhCh [5]. In [6] the behavior of WhCh passengers who suffered incidents (with or without vehicle impact), through in-depth analysis of real accident reconstructions, were analyzed. Results showed that the greater severity damages suffered by WhCh users were caused due to the inefficient or nonexistent use of the restraint systems by the WhCh and his occupant, without disregarding the influence of the vehicle's driver when performing emergency maneuvers during normal traffic. The driver's training whose collaboration will be fundamental, both to perform adequate assistance and to ensure boarding-disembarking safe operations, is also important [7].

Taking into account the results obtained in all the aforementioned previous research, it is clear that the transport service operating agencies are aware of the risk that these passengers suffer under normal vehicle conditions. Some data recorded by the EMT Madrid operator during the last 18 months (since April 2018 to date) indicated the occurrence of about 10 incidents with ChC, that is, one every 2 months, in which the baby or child was dropped from the carriage. Most of the incidents were due to sudden braking or closed curve driving, and others due to ChC badly positioned [8]. The EMT Madrid has a fleet composed by approximately 2300 low-floor vehicles.

It should be noted that mobility problems generated by the transport of ChC not only affect the user groups themselves but also the transport service operators, which must face situations of social rejection due to the refusal to accept admission to the transport services of certain types of busses, either due to the absence of specific regulations or due to the ignorance of the possible solutions to the problem generated with this type of users.

The absence of specific standards that regulate the accessibility of ChC to the vehicle constitutes one of the most common difficulties. **Figure 1** shows some examples of typical cases of the troubles that users traveling with ChC in road public transportation vehicles have faced up to. To overcome some difficulties related to access to vehicle interior, some carriage must do so through the front door with the folded carriage (**Figure 1A**). If the carriage cannot be folded, access must be made through the central door to overcome the difference height between the bus stop and the floor of the vehicle (**Figure 1B**). Finally, the maneuverability of the ChC itself inside the transport vehicle constitutes another one of the barriers to mobility that will have to be faced (**Figure 1C**). Another common problem that users' groups and transport operators have had to face consists of the absence of safety systems to hold the ChC during transport (**Figure 2A**), as well as compatibility between market types of ChC and WhCh models, when sharing the space reserved (**Figure 2B**).

**Figure 1.**

*Examples of the challenges faced by ChC in the access to public transportation vehicles: (A) access with the ChC folded through front door, (B) access with the ChC unfolded thorough central door, (C) difficulties in the* maneuverability *inside the vehicle for accessing to the space reserved to ChC (source: EMT Madrid).*

#### **Figure 2.**

*Examples of the safety conditions in the mobility of ChC in passenger public transportation vehicles: (A) absence of safety systems to hold the ChC unfolded during travel, (B) compatibility of ChC with the WHCHs' space occupied (source: EMT Madrid).*

There have not been many studies related to the problem of transporting ChC in urban busses. One of the few and most prominent has been the ASUCAR<sup>1</sup> research project. In the first phase of this project were analyzed the accessibility and safety conditions which ChC had to face up to in this type of mobility. The study was based on a survey of companies operating public and private transportation services in Spain, mainly in urban areas, with the collaboration of the Association of Urban and Road Transports (ATUC) [9]. Of the more than 70 surveys launched in 2008, the responses of 44 companies were analyzed. The results obtained showed that companies used to regulate the access of ChC to urban transport vehicles by applying internal, local, or regional regulations in 70% of cases; the rest, 30%, did

<sup>1</sup> The research project, *Determination of accessibility and safety requirements in the use of children's carriages in public transport vehicles (ASUCAR)*, was funded by the Spanish Ministry of Science and Innovation during the period 2008–2010, within the Program PETRI (REF No. PET2008\_0328\_01 and PET2008\_0328\_02), coordinated by the Polytechnic University of Valencia (UPV-IDF), and participated by the Polytechnic University of Madrid (UPM-INSIA) and the Municipal Transport Companies of Madrid (EMT Madrid) and Valencia (EMT Valencia).

not apply any rule or left the final decision at the discretion of the driver. Eighteen percent of the companies did not allow access to tandem-type ChC (twin). Only 45% allowed access to unfolded ChC, which should be located in the area reserved for WhCh (34%), of which only 23% established the preference of WhCh over ChC. Only 25% of companies' limited access to one ChC and 34% facilitated the transport of a maximum of two ChC. Only 25% of them forced the ChC to apply their brakes during transport.

At present, there are companies in Spain that operate urban public transport services that have implemented their own accessibility policy and have regulated access to the different vehicle configurations of their fleet to all types of passengers with reduced mobility, including WhCh, electric scooters, ChC, passengers with walkers or suitcases, bicycles, etc. Such is the case, for example, of the Municipal Transport Company of Madrid (EMT Madrid), which developed in 2015 is an internal regulation that facilitates the mobility of different passengers with reduced mobility with different configurations of transport vehicles [10]. In the case of ChC, and depending on the type of vehicle and the existence or not of other PMR users, access of up to four single or double ChC (tandem) is allowed.

#### **1.1 Legal framework for children carriages' travel mobility**

Currently, one of the few international regulations that states the mobility of ChC in road transport vehicles is the UNECE Regulation R107 [11], which explicitly establishes the technical requirements that the spaces reserved for the displacement of ChC in M2 and M3 vehicles must comply. In the UNECE Regulation R107, it is established that transport vehicles legalized according to these regulations must allocate at least one space reserved for unfolded ChC, with minimum dimensions of 1300 mm in length and 750 mm in width. The area reserved for the ChC may be the same as that occupied by a WhCh (if a single reserved space is available), or adjacent to it, in which the carriage must travel in a plane parallel to the longitudinal axis of the vehicle, but without specifying, explicitly, if the orientation of the ChC must be forward or rearward facing. UNECE R107 [3] does not explicitly require the use of any safety system to prevent the carriage and its occupant from being damaged due to sudden maneuvers of the transport vehicle (turning, braking, or accelerating), or in worst-case scenarios, when an impact as a result of an accident occurs. The approach established in this transport configuration, therefore, is based on the use of passive safety systems for the transport of ChC based on backrestraint walls, as due for WhCh.

The accessibility conditions of the ChC must be the same as those necessary for a WhCh, that is, there must be at least one door that allows access to this area, and the carriage must be able to maneuver and move through the interior without problems and without any steps, holes, or uprights that make it difficult to access the reserved place. To prevent the ChC from moving inside the passenger compartment, conditions similar to those required for a WhCh are established when traveling with an orientation rearward facing, that is, the reserved area must be contiguous to one side or the wall of the vehicle, while on the other side, a retractable bar—or equivalent rigid device—that limits the lateral displacement of the ChC must be allocated. At the front end of the area reserved for the ChC, a backrest perpendicular to the longitudinal axis of the vehicle shall be placed, which must meet the same structural and resistant requirements required in the case of WhCh transport.

In addition, the companion person must be able to be attached during the trip to a bar or handle, anchored to the side or wall of the vehicle. The reserved area must have a pictogram indicating that the area is reserved, as well as pictograms on the vehicle access doors through which the ChC has to enter and exit. The reserved area will be completed with a warning device (button or similar), which allows the passenger to request the driver of the transport vehicle to stop at the next stop.
