There are many different types of benefits related to
transportation improvements. Part One of this manual focuses on
user benefits, or benefits that are enjoyed by travelers
that are directly affected by a transportation improvement. User
benefits are determined by travel costs in three distinct areas:
travel time costs, operating costs, and accident costs. Taken
together, the total of these costs is essentially the price that
travelers must pay to travel. When a comparison is made between the
costs of traveling and the number of trips taken at each price
level, a relationship is determined between the cost of travel and
the demand for trips. When all users are aggregated together, the
difference between the travel "price" that travelers are required
to pay and what they would have been willing to pay is the user
benefit affiliated with the trip. Any reduction in travel costs
(i.e., trip price), then, will result in a benefit to the traveler.
For example, with a cost reduction, users who were already making
the trip receive the benefit of making the same trip at a lower
Focusing first on user benefits is appropriate because most of
the economic benefits of transportation projects come from the
reduction in user costs. When trips in a particular corridor are
perceived as costly, perhaps due to long travel times or high
accident rates, travelers sacrifice taking some trips in that
corridor, and the economic activity associated with those trips is
lost. Reducing user costs makes the perceived cost of travel
cheaper, and facilitates trip making and the accompanying economic
activities. By balancing these accompanying user benefits against
project costs, we can determine which projects will provide the
optimal level of net benefits to society.
Obviously, however, a project will also impact people other than
direct users of the facility. These effects are referred to as
indirect benefits or non-user benefits. Examples of
indirect benefits include environmental impacts, effects on urban
growth, economic influences, and the distribution of costs and
benefits attached with the project. The methods for measuring
non-user benefits are different in some ways from the methods used
to measure user benefits. To facilitate exposition of those
differences, non-user benefit measurement is discussed in Part 2 of
this manual, beginning at Chapter 8.
Regardless of whether one examines a project's benefits from the
user or non-user perspective, the general framework for measuring
project benefits is similar. Project benefit estimation requires
that each project being evaluated be compared against some
alternative outcome. The alternative outcome could be a "Base Case"
or "No-Build Scenario" that maintains current facility conditions
into the future. The alternative scenario could also be a different
improvement project. In either case, to conduct the project benefit
analysis, benefit levels are estimated for two different scenarios.
When measuring user benefits, for example, the difference in user
costs (that is, the combined effect on user benefits due to changes
in travel costs, operating costs, and accident costs) is the impact
to the users linked to the project. Since an improvement should
result in a reduction in these costs, the difference in
these cost levels is used to determine the total user benefit of
the project. Measurement of non-user benefits also requires a
comparison of the project outcome with some alternative outcome.
The non-user project benefits are also measured as the difference
of the two outcomes.