Two recent laws are having major impacts on transportation planning and
travel forecasting. Both the Clean Air Act amendments and the 1991
Intermodal Surface Transportation Efficiency Act (ISTEA) emphasize the role
transportation systems play in attaining federally mandated air quality
standards. These two pieces of federal legislation are among the most
important landmarks in a decade-long shift of emphasis in regional
transportation planning. The acts require new, detailed, accurate analyses
of the potential impacts of transportation improvements on congestion,
travel, and land use. What is more important, the strategies developed
to help meet regional air quality standards will affect public
investments in the transportation network and public transit, which in
turn will affect future regional development.
The Clean Air Act was enacted to protect and enhance the quality of the
nation's air resources, to prevent and control air pollution, and to
provide technical and financial assistance to state and local governments
to develop pollution control programs. Congress recognized that the growth
and complexity of air pollution due to urbanization, industrial
development, and the increasing use of motor vehicles posed a danger to
public health and welfare. The act sets national air quality standards and
requires states to curb pollution from stationary and
transportation-related sources. The 1990 amendments significantly expand
the transportation planning requirements previously contained in the 1977
Clean Air Act. ISTEA is intended to develop an economically efficient and
environmentally sound national intermodal transportation system. It gives
state and local governments greater flexibility in addressing
transportation issues and provides funding for transportation programs that
contribute to meeting air quality standards.
Recent litigation in the San Francisco Bay Area pointed up many
deficiencies in the current state of travel modeling and analysis,
particularly in assessing air quality impacts from transportation projects.
Environmental groups challenged the adequacy of transportation planning in
the Bay Area even though the Metropolitan Transportation Commission (MTC),
the regional transportation planning agency, was at the time a national
leader in transportation planning methods. The lawsuit nevertheless
contended that planners had failed to consider the potential land use
implications of new freeway construction and funding decisions, failed to
implement transportation control measures included in the regional
transportation plan designed to reduce traffic and achieve cleaner air, and
failed to meet other federal requirements of the 1977 Clean Air Act linked
to the urban transportation planning process.
Besides challenging the planning process as inadequate, the plaintiffs also
contended its content was flawed—that the standard models being used were
inappropriate to the task assigned them—and therefore the result could
not be relied on for accurate assessments of the air pollution impacts from
freeway construction. The federal court ruled in favor of the plaintiffs
based on the defendants' own planning commitments, and after a couple of
years of legal wrangling over how the defendants would comply with the
court's order, the parties reached a settlement in which the regional
transportation planners agreed to modify their procedures to better address
air quality concerns.
The Bay Area case, which is the subject of this book, is frequently cited
as a threat to the current standard approach to regional transportation
planning, because it holds planners to a heightened standard in meeting
national air pollution goals. Although the case arose before the new
legislation took effect, the court did address the impact of the 1990 Clean
Air Act Amendments, particularly on existing pollution control strategies.
Even prior to the amendments, the 1977 Clean Air Act required regional
planners to incorporate air quality goals into their transportation
planning process to receive federal highway project funding. The court
ruled that the 1990 amendments reinforced those requirements and did not
permit the agencies to relax their pollution control efforts. In brief, the
decision held that existing planning methods failed to satisfy the 1977 act
and by extension would also not be adequate to comply with the 1990
amendments.
The decision has major implications for future planning practice under the
1990 amendments and ISTEA because the court held the defendant
transportation planning agencies responsible for greater proficiency in
predicting regional impacts from freeway construction and upgrading than
most current modeling practice allows. This higher level of analysis has
become mandatory for all states under the new legislation and the EPA
regulations designed to implement it. The lessons drawn from the Bay Area
litigation should serve as a guide to other jurisdictions that do not
presently comply with the federal clean air standards. Unless better
techniques can be devised to assess potential air quality impacts of new
freeways and added traffic, we may expect increasing challenges in court to
slow or halt new highway and mass transit projects.
The case also raised a number of important questions concerning the
relationship between transportation system investment and regional growth.
Plaintiffs argued that when new highways are planned to respond to
forecasts of future land development, their eventual construction will
itself change those land use patterns and that this feedback loop must be
incorporated into the modeling process. Although the court ruled that it
has never been shown that highway construction causes growth in a region
that would not otherwise have occurred, it did hold that highway
construction may indeed affect the distribution of economic development and
residential population within a region. Regional planners in the Bay Area
were required to consider these form-inducing effects of highway
construction, a practice that may well be required elsewhere under the new
acts.
[pp. 1-3]
- Between 1970 and 1974, the EPA tried to implement transport control
measures like mandatory parking fees, HOV lanes, bike paths and gasoline
rationing. Congress curtailed this in 1974. (Refs: 38 Fed. Reg. 30,626,
30,629-30 (November 6, 1973); Donnellan, supra note 24, at
729-732; Battle supra note 24, at 13-16; Energy Supply and
Environmental Coordination Act of 1974, Pub. L. No. 93-319, sec.
4(b), 88 Stat. 247 (1974) (adding sec. 110(c)(2)(B) to the Clean
Air Act, codified at 42 U.S.C.A. sec. 7410(c)(2)(B) (West
1995))).
- There were two lawsuits: one from Citizens for a Better Environment,
focused on stationary sources; and one from the Sierra Club, focused
more on transportation pollution sources.
The basis for the plaintiffs' lawsuit was that the various defendants all
had some degree of responsibility for developing, approving, and
implementing the SIP [State Improvement Plan] for the Bay Area but had failed to achieve the
reductions in air pollution called for in that plan and had failed to carry
out specific portions of the plan designed to improve air quality.
Plaintiffs argued that the court should require the planning agencies to
implement all the components of their regional air quality plan. The
defendants argued that the plan's provisions were advisory and should be
treated with flexibility and should not be literally or rigidly
interpreted. The district court, although flexible and interpretive in some
ways, held that the plan constituted a set of relatively firm commitments
that the state and local defendants would have to follow.
Specifically, the court ruled that the defendants had to implement all the
control measures listed in the SIP and also had to identify and adopt
additional contingency measures when it became clear that the Bay Area
would not achieve the federal air quality standards. In addition, the court
decided that the MTC [Metropolitan Transportation Commission]'s methods for ensuring that highway projects in its
regional transportation plans and programs conformed to the SIP were
insufficient and ordered the MTC to delay work on some existing projects
and postpone decisions on any significant new projects until adequate
procedures were developed. These rulings have already caused planners all
over the country to be much more circumspect about the provisions they
include in their transportation plans. Before turning to the specific legal
issues raised in the case, it will be useful to review the background
leading up to the adoption of the air quality plan that was under attack
and to describe some of its key elements.
[pp. 40-41]
Given the national interest sparked by this decision, what, on a practical
level, can be said to be its impact? By holding that the plaintiffs could
not enforce specific contingency provisions and conformity procedures, it
certainly lends support to efforts by environmentalists and federal
regulators to force states to clean up their air. An opinion by a federal
district judge, though, has limited value as a precedent value. Although it
is binding between the parties to the case, and it can have some persuasive
force in other similar litigation, other state and federal courts are not
bound to follow it. It can, however, affect the direction of federal
regulatory policy. For the EPA, it confirmed that SIP commitments are
enforceable, which will add some leverage to their rule making and
oversight responsibilities. Perhaps buoyed by the success in the Bay Area
lawsuit, shortly after passage of the 1990 Clean Air Act Amendments,
several national environmental organizations notified a number of
metropolitan planning organizations and most state governments
demanding a larger role in the planning process and warned them to
comply with the new transportation requirements or face lawsuits. More
immediately, the decision certainly did have a dramatic impact on
transportation planning in the Bay Area, as the following chapters
illustrate. It forced planners in various state and regional agencies
to seriously consider the relationship between transportation and air
quality. It also pushed them to develop new analytical techniques.
[p. 71]
- In the aftermath, the MTC continued to insist that "highway
construction would, if anything, be neutral or have a net beneficial impact
on air pollution by reducing congestion. Delaying or even stopping highway
construction would have little, if any, positive effect on regional air
quality and could even be detrimental." [p. 93] They viewed stop-and-go
traffic as the primary problem, and presumed that increasing supply to meet
demand was possible.
- One of the main arguments: Sierra Club's expert (Peter Stopher)
argued that the Bay Area was capacity-constrained, with people avoiding
trips or chaining them due to peak hour congestion, while the MTC's
expert (Greig Harvey) argued against this, claiming that users of new highways
were simply shifted from other routes, times or destinations.
- Many of the final results were in favour of the MTC. In 1995, the Bay
Area attained ozone and carbon monoxide standards. In the period since
1965, the population as risen from 4 million to 6 million and the number of
motor vehicles has doubled from 2 million to 4 million, while VMT have
increased from 48 million to 123 million. Data over the 1982 to 1995 period
is notably absent in the book. [p. 197]
- The Transportation Research Board (TRB) appointed a panel of 16
experts in transportation planning, environmental science and air quality
policy to examine the question of whether expanding metropolitan highways
generally contributes to improved air quality by eliminating bottlenecks
and congestion, or generally contributes to worsened air quality by
inducing increases in travel, motivated in part by the Bay Area lawsuit.
Unfortunately, the panel came to no definitive conclusion on this question
[pp. 198, 207]. [3]
- There's a strong need for better understanding of the data
requirements for feedback between the submodels of a typical transportation
model. It's also important to understand the parameter range for which the
model was calibrated: extrapolation will always be speculative, and many
common desirable forecasting operations will be extrapolations into
unknown policy conditions [pp. 200-201].
- The models are often highly precise (decimal places) but have poor
accuracy (often only the order of magnitude is about right). Court
interpretations have often been heavily based on the model numbers, since
they're the only quantitative estimate available. There are many further
implications on the process of transportation planning stemming from this
decision. For example, it may limit planners' willingness to experiment
with untried (and unquantifiable) policy options.
- Modeling urban form is very, very difficult, especially when ethnic
and class differences, etc. are included. See [2].
- Generally, urban modeling has experienced a huge decline of interest
during the Reagan period of the 1980s, with the removal of most public research
funding. Most research retreated to small academic groups, with private
companies' products stagnating. The state-of-the-art at the time of writing
is pitifully inadequate and outdated. The TRB has started on a new line of
research in the wake of this lawsuit, including the Travel Mode Improvement
Program (TMIP) and the controversial TRANSIMS project. [pp. 220-222]
- 1
-
Mark Garrett and Martin Wachs.
Transportation Planning on Trial: The Clean
Air Act and Travel Forecasting.
Sage Publications, Thousand Oaks, CA, USA, 1996.
- 2
-
R.E. Klosterman.
An introduction to the literature on large-scale urban models.
Journal of the American Planning Association, 60(1):41-44,
1994.
- 3
-
Transportation Research Board.
Expanding metropolitan highways: Implications for air quality and
energy use.
Special Report 245, Transportation Research Board, Washington, D.C.,
USA, 1995.
David Pritchard
2007-12-10