This study was carried out to examine the applicability of forest roads as emergency access and evacuation corridor for an alternative to motorways following a prospective earthquake in Istanbul. For this purpose, various disaster scenarios were created in the district of Beykoz and the shortest routes between critical points were determined through network analysis in Geographic Information System (GIS). Results indicated that access was possible between Beykoz city center and shelter, hospital, fire station, disaster management center, and military area via forest roads even if motorways became unusable. However, distance generally got longer and time of arrival increased on the routes of forest road. The increase in time of arrival was attributed to decrease in average cruising speed in addition to the increase in distance. This limitation can be overcome by enhancing the geometric standards of forest roads and completing superstructure operations. Results are important for revealing that forest roads can be used in other fields besides forestry activities, they can strengthen decision support system of managers, and enable first aid crew to reach the scene in the minimal time.