## 6 Discussion  
Although there are few holistic studies on the impact of transportation vibrations on people in buildings, i.e., those receiving vibrations passively, articles in which only one type of passing vehicle is studied also allow for comparison of results. In article [27], the effect of heavy goods vehicles (HGVs) is examined, showing that different types of vehicles have varying impacts, similar to the discussion on metro trains, buses, and trucks. In [28], the impact of tram speeds passing near a residential building on the residents' perception of vibrations was studied. It was found that the speed of the tram does not necessarily translate into vibrational comfort in rooms located near the tramway. Similar conclusions can be drawn from our analyses when comparing the travel time of terms with the VDV or HPVI values. This suggests that tram speed, much like the tram type, has a complex relationship with the vibrational comfort experienced inside buildings close to tram lines. This nuanced understanding underscores the importance of considering various factors beyond speed alone in efforts to minimize the impact of vibrations on residents.  
A very interesting study can be found in [29], which is an in-depth analysis of the influence of tram traffic-induced vibration on buildings damaged by earthquakes, particularly in the context of the Zagreb 2020 earthquake. It explores various aspects of vibration impacts, including the tram type, velocity, and proximity to the buildings, and how these factors contribute to the propagation of existing cracks or cause new damage to the already earthquake-affected structures. Both our analysis and the document underscore the significant role of vehicle type in influencing vibration levels. Just as different types of vehicles (buses, metro trains, trams) were found to have varying impacts on HPVI and VDV, the document further specifies tram types, highlighting how specific tram models contribute differently to vibration levels and potentially to the damage extent of buildings.  
The metro train passage is always studied when complaints from residents appear, as occurred in [30]. Articles focus mostly on the diagnosis of noise and vibrations which appeared due to metro train passages. They focus on how to design buildings located near the metro.  
The document [31] focuses on a comprehensive study of how traffic-induced vibrations affect residential buildings and their occupants, with a specific case study in Istanbul, one of the world's most populous and traffic-congested cities. The research includes surveys of building occupants' perceptions of vibrations, measurements of ground vibrations induced by trains, and numerical modeling of typical residential buildings to assess their responses to these vibrations. Similar to our analysis, [PERSON]'s study highlights the significant role of vehicle type (especially trains) in influencing vibration levels and their perception by residents. This aligns with our findings on the variable impact of different types of vehicles on HPVI and VDV measurements.  
Although there are no comprehensive studies that consider various types of vehicles passing near buildings where people passively receive transportation-induced vibrations, it can be observed from many research results that the type of vehicle is not insignificant when considering vibrational comfort. In addition, a further investigation is planned by considering multi-hazard effects (i.e., wind-induced vibrations on high-rise buildings) estimated through CFD simulations of [32].