## 1 Introduction  
Earthquakes often trigger the closure of the road network, causing obstacles in rescue and evacuation procedures. Efficient mitigation strategies and appropriate emergency plans should consider the probability of road closures in order to ensure rapid emergency management, and to minimize the impact of disasters in terms of casualties, the disruption of activities, and economic losses. Although there are growing studies on the accessibility modeling of road networks for the essential elements of emergency management in earthquake cases, such as operational centers, hospitals, fire stations and emergency areas, the literature that incorporates road closure probabilities into the accessibility analysis is quite limited. An interesting integration can be found in [PERSON] et al. [1]. In the aftermath of a disastrous seismic event, road blockages can be direct or indirect (Figure 1). The former directly affects the road pavement due to ground failures from liquefaction, landslides, and fault ruptures, or through the structural damage of its additional components (bridges, tunnels, retaining walls, etc. ), while the latter are due to the debris distribution generated by the collapse of the surrounding environment. Generally, outside inhabited centers, this distributed debris is due to the collapse of elements in the natural environment (rockfalls and landslides), while inside inhabited centers, it is caused by the collapse of buildings adjacent to road edges (interfering buildings). In urban areas, road blockages due to collapsed buildings are the most important mobility limitation for the road network [2,3]. Therefore, the vulnerability of interfering buildings plays a key role in assessing the seismic risk of an urban road network. In [PERSON] et al. [4], a summary is provided of the different methodologies to develop fragility curves for transportation infrastructures subject to seismic activity; however, the authors focused on the geotechnical effects, and did not consider road blockages from damage to interfering buildings. Analyzing the collapsed buildings triggered by the earthquakes that occurred between 1988 and 2003 in Algeria, Armenia, India, Japan, Mexico, Romania, Taiwan and Turkey, researchers [5] considered ten different damage types categorized into the following five groups (Figure 2): (i) inclined layers; (ii) pancake collapses; (iii) debris heaps; (iv) overturn collapses; and (v) overhanging elements. In the group \"inclined layers\", the structure supporting a floor slab or a flat roof collapses on one side, generating an inclined plane that can affect one floor, several floors, or the whole building. \"Pancake collapses\" are due to the uniform collapse of the structural elements of a floor or of all or some floors (so-called soft storeys). These collapses are typical of reinforced concrete (RC) buildings. They generate modest debris areas on the road pavement. In the group \"debris heaps\", all or some of the structural elements are completely destroyed, generating significant debris areas. Commonly, such collapses are typical of masonry buildings. \"Overturn collapses\" are characterized by two types of damage, namely \"overturn collapse-separated\" and \"overturn collapse\". In the first damage type, the building footprint area is still recognizable, but a new structure (the upper part of the building) can be found nearby. In the second damage type, the building maintains a single body, but the inclination of its vertical axis is changed until the building is completely overturned (in urban areas, complete overturning is often prevented by the surrounding buildings or debris). For this damage type, soil conditions play an important role. Finally, in the \"overhanging elements\" group, the load-bearing external walls are destroyed, but the floor slab or the roof remains in its initial position. Depending upon the building type (RC, masonry, etc.