System dynamics simulation for park management A case study of Glacier National Park, Montana

National park management encounters the challenge of conserving the park unimpaired for the enjoyment of future generations. Many national parks in the world are faced with resource degradation due to overcrowding on roads and trails. The Going-to-the-Sun Road of Glacier National Park in Montana has undergone the same situation, especially after the high increase in visitation over the years since its first completion in 1932. During the rehabilitation project of the road starting from 2007, a free shuttle system was introduced to reduce road congestion. The operation of the shuttle system has received contrasting feedbacks from users, park staff and researchers. The continuation of the shuttle is best considered within the larger context of planning for the Going to the Sun Road corridor. Planning issues, including questions on the shuttle, can be addressed through the use of System Dynamics simulation. In order to evaluate the effect of the shuttle system on road and trail use, a System Dynamics model was built for a typical busy day in July. The model helps reveal visitor behavior and explore possible policies to improve road and trail management. Three sub-models are linked together including the Traffic sub-model, Shuttle sub-model and Trail sub-model. Results suggest that the shuttle helps reduce traffic congestion but does not lessen parking lot congestion. The main reason is because a significant number of cars fail to park and the number highly exceeds parking lot capacity. The shuttle also puts more people on trails and the Logan Pass Visitor Center. The increase ranges from 18 to 22%. Further analysis reveals that when there are more annual visitors, major parking lots will become full earlier and stay full longer during the day. Increased annual visitation will add more people on trails but the increase is minimal due to limited parking space at Logan Pass. In addition, making the Logan Pass Visitor Center more attractive to lengthen visiting time would indirectly reduce the number of car people on surrounding trails.