Probabilistic and statistical relationships between number of vehicles and number of visitors at a geologic site in a National Park

The National Park Service needs to establish in all of the national parks how large the parking lots should be in order to enjoy and preserve our natural resources, for example, in the Delicate Arch in the Arches National Park. Probabilistic and statistical relationships were developed between the number of vehicles (N) at one time in the Wolfe Ranch parking lot and the number of visitors (X) at Delicate Arch 1.5 miles away in the Arches National Park, southeastern Utah. The value ofN is determined such that 30 or more visitors are at the arch only 10% of the time.