Incremental high-speed rail is an intercity passenger transportation c
oncept that has grown from the combined pressures of increasing airpor
t and highway congestion, of fiscal constraints on the construction of
new transportation infrastructure, and of sensitivity to environmenta
l concerns. Incremental high-speed rail has a strong potential role in
the new era of intermodal transportation planning heralded by Intermo
dal Surface Transportation Efficiency Act (ISTEA) of 1991. There are c
urrently six designated incremental high-speed rail corridors each add
ressing the unique issues associated with such projects.