PREFACE
The purpose
of this analysis is to examine some of the many energy consumption
patterns for urban passenger transportation which are conceivable
for the last quarter of this century. No attempt is made to predict
what transportation will be like in the future; rather, we
lay out a spectrum of possibilities (called options) and estimate
the energy consumption which would result from the policies,
preferences, and living patterns assumed for each of the options.
No option is viewed as more likely than another, and some
possibilities—such as telecommunications, whose impact on
transportation is totally uncertain—are not included.
It is
important for the reader to understand which parts of the analysis
are rigorous and which are not. The analysis was carried out in
three stages: (1) qualitative development of the options; (2)
quantitative evaluation of the energy consumption resulting from
each option; and (3) assessment of the results. While we have
attempted to be as objective as possible, the set of options chosen
here certainly does not exhaust the range of possibilities.
Obviously the choice is subject to individual judgment.
The first
stage—the construction of the options—is the least
rigorous. Even the most sophisticated modeling cannot estimate with
certainty how people's travel habits will be affected by fuel price
increases, legislative actions, and so on. For each option we
discuss how the exact quantities (trip length, fraction of trips by
auto, etc.) which define the option might represent people's travel
habits in the future. Common sense was often the best tool
available to make the quantitative travel estimates consistent with
the qualitative assumptions of each option.
The most
rigorous part of the analysis is the calculation of
the