Civil Engineering Reference
In-Depth Information
economy. The expansion of the scope of EIS even risks shifting to economic
and social analyses (which are likely to be vastly simplified for the sake of
fulfilling legal requirements) the analytical time that should have gone into
studying true environmental consequences. The rest of this chapter eschews
these accretions to the EIS process. We focus on the core of the process,
the assessment of effects that are “environmental” in the ordinary sense.
ASSESSING ALTERNATIVES
When the need to consider every regulation is put aside, and the nonenvi-
ronmental requirements are stripped away, the EIS at its core presents a logi-
cal and comprehensive procedure for assessing environmental consequences
of civic projects. For a given bridge proposal, the EIS attempts, in effect, to
catalog all significant impacts.
The EIS begins by evaluating alternative alignments for the bridge.
What is more, it considers the possibility that the city would be better
off with no added bridge at all. Study of the “no bridge” alternative is
especially important in areas where the public's main motive is to reduce
traffic congestion. A new bridge would, after all, seem to promise that it
will speed up the traffic.
As we have already mentioned, however, much research in transporta-
tion planning has shown that, in congested cities, emptier roads and faster
travel times make more people decide to travel by car or make them take
more frequent or longer trips. This is known as
induced travel demand.
Instead
of resolving congestion, the added traffic lanes that a new bridge opens up
induce new travel, adding to the sum total of traffic in the area, eventually
restoring the congestion the new bridge was meant to solve. For this reason,
at the early stages of an EIS, environmentally aware transportation planners
should consider
travel demand management
policies instead of a new bridge.
For example, faster emergency response (to clear up traffic accidents and
clear away disabled cars) can do much to alleviate traffic congestion without
the need for construction, and at much less cost.
In Great Lake City the travel demand management option doesn't
apply. The city's downtown is not congested. The very purpose of the new
bridge to the promontory is to increase waterfront access, land development,
economic activity, and recreation around the harbor. Toward that goal (if
water taxis are shown to be inadequate for the purpose), there is no good
alternative to a new bridge. Early in our hypothetical EIS process, therefore,
the agencies conducting the EIS reject the “no bridge” option.
Now EIS planners must consider alternative alignments. It may seem
obvious that bridge planners, architects, and engineers would do so, whether
the EIS requires them to or not. They do, after all, have to find the location
