*3.1. Bus Comfort Level*

Onboard bus comfort is an essential aspect of the satisfaction perceived by bus passengers. The quality of the bus transit in terms of passenger comfort is usually an extensive set of partial

influence factors, which are very difficult to quantify. Hence, this is usually the reason why they are not included in the various indicators for assessing the quality of public transport. Therefore, the group of indicators describing the comfort of travel include the inconvenience of travel resulting from the limited availability of seats or even standing in the vehicle. The literature most frequently mentions the nuisance ratio, and the nuisance ratio or seat occupancy rate, for different reference levels in the form of standards for the number of seats in a vehicle. The driving discomfort coefficient μ*j* determines how many times a journey by public transport in specific conditions is more onerous in comparison with a journey where the passenger sits and the filling of standing places is small (0.5 passenger/m2). The driving discomfort μ*j* is calculated from the following formula (based on [39]):

$$
\mu\_j = 0.8 + 3.6 \times (q - 0.15)^2 \tag{1}
$$

where *q* is the relative onboard occupation calculated as:

$$q = \frac{N}{\mathbb{C}\_N} \tag{2}$$

where *N* is the absolute onboard occupation (number of passengers in the vehicle), and *CN* is the nominal capacity of the vehicle (using the area of standing places as 0.15 m<sup>2</sup>/person).

The onboard comfort level can be defined based on the calculated value of the driving discomfort μ*j*, and it could be one of the below possibilities [39]:

