The National Parks are becoming increasingly crowded and congested and the National Park Service is exploring ways to motivate visitors to use alternate forms of transportation (e.g., busses and trams). Visitors, however, are resisting this initiative. A recent survey of park visitors by WTI (Moore & Kelly, 2002) found that a significant percentage of visitor would be willing to ride on a more flexible system of transit busses in Yellowstone Park if it allowed riders to set their own itineraries and schedules. Advances in computer and display technology may also provide a path to this goal. Portable computing and display devices such as palm computers, notebook computers, global positioning system (GPS) receivers, and virtual reality goggles and headphones are becoming increasingly common for travel and tourism applications. These technologies are already frequently used for location, route selection, and identifying nearby destinations and attractions. Providing interactive information support concerning the flora, fauna, geography, geology, ecology, history, and culture of a tourism site is a logical extension of these functions. A current WTI project is exploring the features of an alternative transportation system, especially the information system component, for Yellowstone National Park. This project is an extension of that preliminary effort.During the initial effort, WTI is developing a low-level prototype of a candidate Yellowstone Park portable information system based on the results of the recently completed front-end analysis. This project continues that effort through at least one additional design-evaluate cycle to produce a higher quality and fidelity prototype based on Internet technology. It is expected that additional functionalities will be added to the Internet-based prototype as a result of further analysis and of the planned evaluations. In addition, the functionalities may be updated according to decisions made by the NPS on the operational philosophy of the alternative transportation systems.During the initial effort, WTI has become involved with the NPS alternative transportation process. As part of that effort, we participated in a national design charette that developed requirements for the new vehicles. During this project, we will maintain contact with NPS headquarters staff to remain abreast of design decisions that would affect the functional requirements for the portable information system. We will seek opportunities to provide design inputs, based on the surveys and focus groups completed this summer and to help guide design decisions.