In accordance with the Landslide Disaster Countermeasures for Landslide Disaster Prone Areas Act, which went into effect in April 2001, areas considered vulnerable to landslides are designated as a Landslide Disaster Alert Area and issuing warnings and evacuation recommendations is promoted when heavy rain is expected. Roads neighboring areas prone to landslide disasters may be designated as both a Landslide Disaster Alert Area and as a Road Zone. In such areas, both the warning and evacuation standards for landslide disasters and standards for expressway traffic regulation apply. And therefore, to satisfy both standards it is important for the road operator and government to work together and build an evacuation system considering the size of the damage and the features of the two standards. In this study we have indicated the points to note for road disaster prevention by studying expressway routes in six prefectures in Japan operated by the three companies of NEXCO (Nippon Expressway Company) and confirming how many areas fall under the two standards and how those areas will be affected by heavy rainfall, and by comparing and analyzing the effects of different precipitation patterns and other differences when rainfall and other criteria exceed both standards.