## 3 Results and Discussion  
### Digital Map of Public Transport  
The transport lines and stations were georeferenced in relation to the street layer [51] extracted from OSM and correlated with the information found on the operator's website [54] about the lines and the approximate positions of the stations' locations on the city map.  
The map in Figures 5 and 6 confirms that the Bucharest city area and, especially, the residential areas are well covered by the surface public transport.  
The tram network (density: 1.18 km/km\({}^{2}\)) has a radial network consisting of only one circular line (inner ring) and is remarkably extensive (Figure 7), but it is discontinuous in the central area of the city. Based on the present map, a fast decision on reconnection may be taken by the public transport operator when referring to the redesign of the tram transport schedule.  
Since the accessibility of the public transport network influences travel demand and urban development [58], its evaluation is necessary for determining the performance of the public transport system. In Figure 8, we show the determination of the isochrones at a walking distance of 400 m (5-min isochrones) from each stop/station using the buffer feature of QGIS based on a fixed distance, considering an average pedestrian speed of 4.8 km/h. For the present research, we used radial isochrones, taking into consideration the fact that Bucharest has a plain topography, does not change much in elevation, has facile connections between main roads and public transport, and has dense residential areas.  
Figure 4: Previewing the vehicle position in stations. (**a**) In DB Manager. (**b**) In pgAdmin using the Geometry Viewer.  
Figure 5: Administrative area and public transport network in Bucharest (blue line—bus network; green line—trolleybus network; red line—tram network) (© OpenStreetMap contributors).  
Figure 6: Residential areas and public transport network (© OpenStreetMap contributors).  
Based on the map above, we concluded that, in general, public transport stations can be accessed relatively easily by the populations living in the residential areas, but there are neighborhoods, especially those with low density (single-family homes in the residential area).  
Figure 8: Accessibility of public transport stations (isochrone 400 m) (© OpenStreetMap contributors).  
Figure 7: Tram network and tram stations (© OpenStreetMap contributors).  
neighborhoods of the South-Western and North-Western areas of the city or in newly developed districts on the outskirts of Bucharest), where the distance to the nearest station is more than a 400 m walking distance.  
To increase the accessibility of the main public transport network and the sustainability of last-mile transport, we recommend a future study for the introduction of additional services. The latest research studies [59; 60; 61] reveal that new forms of shared e-mobility services are attractive for people in EU cities with similar socio-demographic characteristics, and are well received in remote areas with limited possibilities for reaching the main public transport network. Therefore, e-micro-mobility services, on-demand e-transport services, or services based on the use of autonomous and connected vehicles can be used. Thus, the use of sustainable means of transport could be encouraged to the detriment of transport by personal cars.