All transportation modes can be assessed in terms of their ability to transport people efficiently over long distance (throughput) and their ability to efficiently deliver people to a geographically disperse set of origins and destinations (accessibility). In highway transportation system planning the terms throughput and accessibility are used to describe the somewhat conflicting requirements of mobility for a system to provide high-speed movement across great distances as well as make land areas, and their associated housing and services, accessible to the largest number of people. The understanding of this interrelationship of throughput and accessibility as it applies to existing modes of transport, and as it applies to current market development forces is required to begin to identify the attributes needed for the next generation of innovative transport. The emergence and proliferation of new methods of transport and their associated infrastructures throughout history can be viewed as major strides forward in the throughput accessibility spectrum. New modes with greater efficiency of linking long distance trips to more limited access environments provide new paradigms for linking homes and services to the trunk of the existing networks. The developed infrastructure in North America exhibits the need for innovative improvement in the throughput-accessibility spectrum in activity centers such as retail, business, and housing districts as well as at university, hospital and airport campuses. In such places the current parking, pedestrian and vehicle congestion inhibit the efficient use of either vehicles, or existing transit options to service such environments. This paper identifies the mobility requirements of such environments, characterizes the properties of an innovative system to meet the demand, and provides evidence of such systems currently in development. An effective solution for these slower speed and smaller scale areas can provide synergistic benefits to the entire transportation system in North America, while also laying the ground work for a new growth pattern that takes advantage of the strengths of existing modes, while improving mobility, decreasing congestion, and addressing more long-term land development sustainability concerns.
Abstract