Modeling and Analysis of the Road Network Status in Gorgan City during an Earthquake

Abstract

The condition of transportation networks after an earthquake and the timing of emergency response are of paramount importance. It is necessary to consider the level of vehicle services in urban areas based on traffic networks and their constraints. The aim of this research is to provide a vulnerability analysis of the designed transportation networks in Gorgan City, which is a highly earthquake-prone city. In this study, after determining the influential criteria based on expert opinions through the collection of questionnaires that were prioritized by 20 specialists and after examining the questionnaire's reliability using Cronbach's alpha, a factor analysis was performed to identify the important factors affecting post-crisis service delivery to individuals. Additionally, a questionnaire was prepared for drivers who experienced earthquakes while driving, and their reactions to earthquakes were analyzed. In the factor analysis, factors such as access to the communication network with the performance of arterial roads grade 1, attention to bridges, compliance with distances and the protection of rivers and streams, access to the communication network with the performance of arterial roads grade 2, and others were prioritized. It was found that access and transportation networks had a significant impact on these factors.

Furthermore, since the research method is spatial and network analysis in a GIS environment, all influential factors (such as access to road networks with high penetration, road service levels in post-crisis conditions, travel time, route performance, network-related distances) in Gorgan City were analyzed using GIS network analysis. Finally, considering the recognition of various layers in the current network and access to emergency vehicle points, the status of road networks after a crisis was analyzed. In the final part of the study, to control appropriate access to various areas of Gorgan City regarding 11 emergency bases, network analysis tools and their criteria, such as travel time, road performance, distance, etc., were used to analyze the functional radius of these bases. The network analysis output showed that all stations are in desirable positions, with the difference that in some areas with a lack of service level in the city's road network, several fire stations, Red Crescent, etc., are needed for reinforcement.