## 3 Results
Figure 2: Clusters (inputs sorted by overall importance). Figure 2 summarizes the outputs from the two-step cluster analysis. This figure shows that the fourth cluster includes 147 drivers; this group has the largest representation in the comparison, unlike the third group. The color scale demonstrates that the three most important factors in differentiating the drivers into the four groups are a lack of jobs, loading/unloading problems and traffic congestion. In addition, some boxes show which category of a given variable has the most frequent representation in a given cluster. In other words, we find that drivers in the third cluster do not violate social legislation when loading/unloading goods or due to traffic accidents or traffic jams, as well as when returning home. However, all these drivers experience problems due to the lack of free parking spaces. The fourth cluster consists of almost 50% of truck drivers from domestic road freight transport. This group does not violate the social legislation at all due to a lack of free parking spaces or parking areas. Moreover, the majority of truck drivers do not violate social legislation for several reasons, such as traffic accidents (almost 67%), complications in meeting the loading or unloading deadline (less than 88%), poorly planned transport routes (more than 90%) and driving home (almost 80%). These drivers do not reduce their daily or weekly rest times. Finally, less than 65% of the truck drivers paid the highest fine for the violation of traffic regulations or social legislation, which was up to EUR 100 (if at all). The first cluster consists mainly of truck drivers from international road freight transport (more than 50%). These truck drivers violate social legislation for several reasons, such as traffic accidents or traffic jams (more than 92%) and a lack of free parking spaces or parking areas (more than 95%). On the other hand, these drivers mostly do not violate social legislation due to complications in meeting the loading or unloading deadline (100%), driving home (almost 60%) and the poor planning of traffic routes (more than 95%). Moreover, these drivers rarely cut their daily or weekly rest times. Finally, these drivers pay fines of up to EUR 100 (if at all) (54 respondents) or from EUR 101 to EUR 500 (49 respondents). The second cluster consists mainly of truck drivers from domestic and international road freight transport. These drivers violate social legislation for several reasons, such as complications in meeting the loading or unloading deadline (more than 85%), driving home (almost 52%), a lack of free parking spaces or parking areas (more than 88%) and traffic accidents or traffic jams (almost 76%), compared to the poor planning of traffic routes. The results show that almost 71% of the drivers do not violate social legislation due to poor travel planning. As in the previous clusters, this cluster demonstrates that the drivers do not reduce their daily or weekly rest times. Finally, these drivers pay fines of mostly EUR 101 to EUR 500 (more than 41%). This group represents the most dangerous group of truck drivers. The third cluster, as with the second, is mainly composed of international road haulage drivers (almost 47%). These drivers violate the social legislation for free parking spaces or parking areas (100%). On the other hand, the social legislation is not violated at all due to traffic accidents or traffic jams (100%), driving home (100%), complications in unloading or loading deadlines (100%) and the poor planning of traffic routes (almost 100%). Moreover, these drivers do not reduce their daily or weekly rest times. Almost 60% of these drivers paid the highest fines of up to EUR 100 (if at all). This group consists of considerate drivers with no tendency to violate the social legislation, except in the case of a lack of free parking spaces. Figure 3 compares all four clusters.