The fundamental purpose of the National Park System is resource preservation. Visitors can experience and learn about their natural and cultural heritage in parks. Most visitors arrive by private auto and, in some cases, this has begun to threaten the very resources parks were created to protect.

Congestion in many national parks causes lengthy traffic delays and noise and air pollution that substantially detract from the visitor's experience and overall resource protection. Recognizing that more park roads and more parking lots are not the solution, the introduction of visitor transit systems help to alleviate traffic problems and make parks more accessible. Park roads and visitor transit systems are intended to enhance visitor experience while protecting park resources. Transportation is, in many ways, the connection between the National Park Service mission of resource protection and visitor enjoyment.

Since the 1920's, the National Park Service has developed transportation systems in the national parks primarily for the private auto. The distinct character of a park road or parkway play a basic role in setting this essential unhurried pace. Consequently, park roads are designed with extreme care and sensitivity with respect to the terrain and environment through which they pass -- they are laid lightly on the land. There are currently over 8,055 miles of roads and parkways, 1,252 bridges, 60 tunnels and extensive parking facilities. To solve the growing congestion problem throughout the Service, there are 110 visitor transit systems in 98 parks that vary in size ranging from single vehicle and bus fleets to water transit.