## 4 Results and Discussion  
To compare the values of LOS related to the scenarios of the examined bridge, the evaluation is focused on the estimation of the travel time which can be a good measure of estimation to compare the scenarios. In fact, the travel times are extracted for the destination of origin that has the highest number of requests in each scenario. The evaluation of the density and relative average speed is strictly connected to the service level of the bridge and its various parts (ramps and areas). The flow and capacity are highlighted by the LOS value from A to F values in accordance with the Fruin model as described in Table 7 below. Figure 3: Trajectories of pedestrians considering Viswalk trajectories output. In accordance with the LOS definition of Table 7, the pedestrian speed in the different scenarios can be inserted within the range 0.15-1.1 m/s as defined by the graph in Figure 4.  
In particular there is a reduced speed variation in normal scenario conditions with 1.500 ped/h all areas and ramps instead an incisive difference denotes maintenance and maintenance with evacuation as the areas of possible transit are covered. The density value according to the HCM standard, as shown in Table 5, is also estimated. Once the model has been calibrated it has been shown that the results obtained by micro-simulation reflect the realistic results for the basic scenario (daily situation) with 1.500 ped/h and maximum daily scenario with 3.000 ped/h. The other scenarios have been defined and simulated in order to prevent congestion and related problems. Considering the data obtained through the calibration and validation of the model, the micro-simulation results are defined in terms of the density (number of pedestrian/m\({}^{2}\)) as shown in Figure 5. It is possible to see that the scenario titled \"4 th\" relating to the partial maintenance activities increases the density to a value double compared to the flow conditions in daily conditions with 3.000 ped/h. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**LOS**} & **Density** & **Space** & **Flow Rate** & **Av. Speed** & **Capacity v/c** \\  & **(ped/m\({}^{2}\))** & **(m\({}^{2}\)/ped)** & **(ped/min/m)** & **(m/s)** & **Ratio** \\ \hline A & \(\leq\)0.27 & \(\geq\)3.24 & \(\leq\)23 & \(\leq\)1.3 & 0–0.3 \\ B & 0.43–0.31 & 2.32–3.24 & 23–33 & 1.27 & 0.3–0.4 \\ C & 0.72–0.43 & 1.39–2.32 & 33–49 & 1.22 & 0.4–0.6 \\ D & 1.08–0.72 & 0.9–1.39 & 49–66 & 1.14 & 0.6–0.8 \\ E & 2.17–1.08 & 0.46–0.93 & 66–82 & 0.76 & 0.8–1.0 \\  & \(>\)2.17 & \(\leq\)0.46 & variable & \(\leq\)0.76 & variable \\ \hline \hline \end{tabular}
\end{table} 
Table 7: LOS values in accordance with Fruin model. Figure 4: Speed results in accordance with different monitored scenarios. Figure 5: Density evaluation in accordance with different monitored scenarios. An increase of 10-15% of the density value compared to standard conditions is obtained in the case of evacuation. In literature it is found that the average speed of the elderly is 0.92 m/s [62] similar to that of a child accompanied by the mother or dragging the baby stroller. Generally and but adult has an average speed of about 1.6 m/s with a fast pace while the speed of a normal step is 1.2 m/s. These speeds are assumed in an unconfined space. In the case study it is necessary to consider the presence of the slope, the presence of steps and the presence of a geometry that limits the movements decreasing these values by about 20-25%. This reduction is justified by the evacuation scenario allowing escaping only in one direction along the bridge and therefore the accumulation of people does not allow moving faster than other cases in which there is the presence of more space for the movement of each walker. In the graph, it is possible to see a speed value between 0.4 and 0.6 m/s during the evacuation and maintenance phase with 3.000 ped/h. This value depends on the first case from the univocal escape direction and the accumulation effect of the people blocking the path by reducing speed.