The relationships were analyzed among the factors affecting the travel mode choice between government vehicles and private vehicles used for the evacuation of people in areas experiencing floods and landslides. The relationships were developed using a utility function to predict the probability and proportion for selection of the travel mode in future evacuations based on binary logistic regression. Three models were developed using different analytical factors based on the survey data of a sample group of people in the Mae Pong watershed, Laplae district, Uttaradit province, Thailand. It was found that the factors affecting the selection of travel mode in all three models consisted of sex, household size, families with young members, education, car ownership, experienced a disaster, recognition of shelter location, safety of evacuees while evacuating, reaching the destination quickly, convenience of vehicle access, proportional family management for evacuation, ease of the evacuation procedures of mode, and difference between travel time and walking time to the assembly point. Models 1, 2, and 3 could predict with accuracies of 78. 40, 73.46, and 75.30 percent, respectively.

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Flooding and landslides have been a significant hazard in Thailand, especially in steep areas. This study aimed to find suitable evacuation routes for future disaster prevention planning and management by the local authority appropriate to the needs of affected people living in steep areas of Uttaradit province. Evacuation routes were analyzed using the trip assignment model with the optimization technique according to the shortest path and 20 vehicles (pickup trucks) used for organizational planning. The results showed evacuation with the group would take more time than for ungrouped people by almost half an hour, but the number of vehicles could be reduced by one. In addition, for both ungrouped and grouped types, increasing the number and speed of the vehicles decreased the evacuation time by about 20 minutes if the local authorities increased the number of existing vehicles from 20 to 30 and allowed a vehicle speed of 30 kilometers per hour. The information for evacuation management and period obtained in each simulation from this research would be beneficial for determining evacuation notification periods. The results could be used as guidelines for other local authority plans in steep or similar risk areas where efficient evacuation is necessary due to flooding and landslides. Important requirements can be added to facilitate evacuation, such as the road capacity during the evacuation, an alternative route during flooding even and a plan for clearing roads affected by landslides.