NEPA and Environmental Planning : Tools, Techniques, and Approaches for Practitioners - Chapter 7 docx

However, as discussed above, it is reasonably clear that a cumulative impact assessment CIA must be performed before an agency can conclusively determine that the impacts of an action ar

Assessments

In the early 1970s, federal agencies had no option but to prepare an environmental impact statement

(EIS) as many actions could not be immediately excluded as being clearly nonsignificant

Conse-quently, EISs were frequently prepared only to reach the conclusion that no significant impacts

existed In 1978, the Council on Environmental Quality (CEQ) responded to this problem by

creat-ing an environmental assessment (EA), the third level of National Environmental Protection Act

(NEPA) compliance designed to provide an efficient mechanism for bridging the gap between the

categorical exclusion (CATX) and EIS

When the CEQ created the EA, it believed that the EIS would still be the principal instrument

used for evaluating impacts Instead, EAs have become the principal instrument used for evaluating

impacts This observation is supported by the fact that, on an average, approximately 100 EAs are

prepared for each EIS Moreover, the CEQ estimates that 30,000–50,000 EAs are prepared each

year compared with just 300 to 500 EISs.1

This chapter describes the EA process and its documentation requirements For a more

in-depth discussion of the EA process, the reader is directed to the author’s companion book, Effective

Environmental Assessments.2

7.1 OVERVIEW

When challenged, an EIS is often easier to defend than an EA because an EA must prove that none

of the potential environmental impacts is significant or, if one is, that it can be adequately mitigated

In contrast, there is no such requirement for an EIS

Additionally, because of its smaller size, a judge is more likely to take personal interest in an EA

and actually read through it Thus, an EA may receive more rigorous judicial review than an EIS

Project advisories have taken note of this fact and have revised their strategies accordingly As a result,

in recent years agencies have witnessed a movement away from challenging EISs as many opponents

have refocused their efforts instead on EAs, considering them to be more vulnerable targets

Most agencies have not remained docile in the face of greater opposition Evidence suggests

that the quality of EAs has generally improved and, consequently, agencies have been become more

successful in defending their findings of no significant impact (FONSI)

As illustrated in Figure 1.1, the preparation of an EA is necessary for federal actions that cannot be

excluded under a CATX and for which the agency has not prepared an EIS An EA can serve any

one of the following three objectives (§ 1508.9):

1 Briefly provide sufficient evidence and analysis for determining whether to prepare an EIS

or a FONSI

2 Aid an agency’s compliance with NEPA when no EIS is necessary

3 Facilitate preparation of an EIS when one is deemed necessary

The most important function of an EA is, used as a screening device, to evaluate actions to

determine if they may result in a significant impact, requiring the preparation of an EIS To justify

issuing a FONSI, an EA must provide clear and convincing evidence that the proposal would not

result in any significant impacts or that any identified significant impacts can be mitigated to the

point of nonsignificance

Table 7.1 compares some of the basic traits and differences between EAs and EISs Three principal

reasons why EISs are longer and more complex:

EIS has more extensive documentation requirements It also requires more extensive cedures in preparation and issuance

pro-EIS public participation (scoping and reviewing the draft pro-EIS) usually raises issues and concerns that require more analysis and explanation

EIS must thoroughly describe and analyze the significant impacts (which by definition are not at issue in an EA qualifying for a FONSI) and show how decisions about the action are related to an understanding of these impacts

EIS must rigorously explore a range of reasonable alternatives, while an EA typically vides a more cursory review of these alternatives

Comparison of an EA with an EIS

The principal purpose is to determine if the proposed

action would result in a significant impact requiring

preparation of an EIS.

The question of significance is no longer at stake The EIS is prepared to support decision-making by identifying and evaluating alternative methods for meeting the purpose and need and mitigating the impacts.

The proposed action can only be pursued if its impacts are

insignificant or can be mitigated.

An agency may pursue any analyzed alternative regardless of the resulting impacts.

A substantial change in the project would normally

require preparation of a new NEPA document

An EIS reviews a range of reasonable alternatives A substantial change is therefore less likely to result in a delay since it may already be covered in one of the alternatives.

A different alternative may simply be chosen by supplementing the record of decision (ROD).

No restrictions exist regarding who may prepare an EA

(federal agency or a contractor).

A party may not prepare an EIS if it has a financial or other interest in the outcome (conflict of interest).

EAs are normally substantially faster and cheaper to

prepare.

EIS are typically more complex, lengthy, and expensive.

The analysis normally focuses on the proposed action

Other alternatives are usually given only cursory review.

Substantial treatment must be devoted to each of the reasonable alternatives investigated.

While an EA is a public document, a formal public

scoping process is not normally required under the

regulations An EA is not normally required to be

publicly circulated for formal review and comment,

as is the case for an EIS (however, many agencies now

do this).

EISs require a much larger degree of public involvement.

A formal public scoping process is required EISs must be publicly circulated for review and comment.

EAs are not typically supplemented A substantial change

normally requires preparation of a new EA.

EISs may be supplemented if there is a significant change in the action, information, or circumstances.

EAs are often more susceptible to a successful legal

challenge.

If challenged, an EIS is frequently easier to defend.

No requirement exists to consider mitigation measures Mitigation measures must be analyzed.

7.1.3 T IME P ERIODS

Preparation of EAs must be so timed that they can be circulated at the same time as other

plan-ning documents (§ 1501.2[b]) The CEQ has advised agencies that an EA process should normally

require a maximum of 3 months to complete and generally need substantially lesser time.3 In

practice, however, many agencies report that the total process normally exceeds this time frame

The following section provides a thorough review of the process requirements governing the

prepa-ration, review, and approval of an EA and a FONSI

7.2 PREPARING AND ISSUING THE ASSESSMENT

Figure 7.1 depicts a generalized procedure for preparing an EA If the agency is uncertain whether

an action would result in a significant impact, it may choose first to prepare an EA to determine if

the action qualifies for a FONSI This is the course normally taken, since preparing an EIS requires

substantially more effort

In cases involving an applicant (i.e., a nonfederal entity applying for a federal permit, license,

or approval), preparation of the EA must begin early in the process and “no later than immediately

after the application is received” by the agency (§ 1502.5[b])

An EIS must be prepared either by the agency or by a contractor who has signed a

disclo-sure statement indicating that it has “no financial or other interest in the outcome of the project”

(§ 1506.5[b]) No such requirement exists for contractors assigned the responsibility of preparing

an EA (§ 1506.5[b]) The agency, however, is responsible for evaluating the environmental issues

involved in the project and also assumes legal responsibility for their scope and content

After a decision is made to prepare an EA, the most appropriate level of public involvement must

be determined The stage is now set for initiating internal (and if applicable, public) scoping

(see first box, Figure 7.1)

Consultations with outside authorities and agencies are also initiated, as warranted This step is

important, as revealed by a case in which an agency reported that the NEPA process was

particu-larly useful in helping the state and the Indian tribe concerned to resolve their differences about a

proposed action.4

While the CEQ NEPA Regulations (Regulations) do not specifically require an agency either to

incorporate or respond to public comments in an EA, such practice is highly recommended Where

appropriate, either public hearings or meetings should be conducted Criteria for determining if

these are warranted include (§ 1506.6[c]):

Circumstances where there is substantial interest in holding a hearing or where an mental controversy is involved

environ-A request for a hearing is made by another agency with jurisdiction over the action, ported by reasons why a hearing would be helpful

sup-The CEQ has stated that EAs are to be made available to the public and that agencies are to give

public notice of their availability (§ 1506.6[b]) The goal should be to notify all interested or affected

parties.5 Repeated failure to notify interested parties or the affected public could be interpreted as

a violation of the Regulations

A combination of methods may be used to notify the public For instance, appropriate notification

for proposals of national interest might involve publishing a notice of availability in the Federal

Register and national publications as well as mailing the notice to interested national groups

•

•

7.2.1.1 Public Notification

Identify a need for taking action.

Determine that an environmental assessment (EA) will be prepared.

Determine appropriate level of public involvement Initiate scoping Initiate any applicable consultation.

Define reasonable alternatives.

Integrate any other agency planning processes with the EA.

Proceed with the action.

Implement any applicable mitigation and/or monitoring.

Issue finding of no significant impact (FONSI).

Prepare environmental impact statement (EIS).

Significant impacts?

Mitigate impacts?

Investigate proposed action and alternatives Analyze impacts.

Finalize draft EA Perform internal review and incorporate comments.

Make EA publicly available.

Decision-maker reviews EA to determine if any impacts are significant.

In other cases, appropriate notification for a site-specific proposal, such as publishing notices in

local newspapers, may be sufficient

7.2.1.2 The Public Review Process

While EAs must be made publicly available, the Regulations require no public comment, review,

and incorporation period Thus, agencies neither are specifically required by the Regulations to

respond to public comments nor are EAs and FONSIs required to be filed with the U.S

Environ-mental Protection Agency (EPA)

From an agency’s standpoint, thoroughly involving the public in the review of an EA can be

distinctly advantageous For example, in some situations, courts have ruled that an agency cannot

be forced to prepare an EIS if the plaintiff has had ample opportunity to dispute the EA and FONSI

process but failed to do so

7.2.1.3 Consultation

As appropriate, agencies are required to consult with other agencies in preparing their NEPA

docu-ments Such consultation facilitates a more thorough analysis (§ 1501.1, § 1501.2[d], § 1502.25)

While the direction provided in § 1502.25 is directed at the preparation of EISs, it is also interpreted

to be equally applicable to EAs This is evidenced by the fact that an EA is required to list “…

agencies and persons consulted” (§ 1508.9[b])

Chapter 2 of the companion text Environmental Impact Statements provides additional

infor-mation that may be of use in promoting public involvement.6 The EA process is integrated with

other planning studies or analyses (see second box, Figure 7.1)

7.2.1.4 Case Law

A U.S Court of Appeals concluded that the Army Corps had complied with the NEPA regulatory

direction to involve the public in preparing an EA The court held that the agency met the “to the

extent practicable” requirement by issuing public notice of the proponent’s application, conducting

two public hearings, responding to public comments in the EA, and conferring with environmental

agencies The court did not agree with plaintiffs that the agency should have prepared a draft EA

for public comment This case is in contrast to a second case described below in which the agency

had a much more limited public involvement process

In the second case, a district court held that the Forest Service violated NEPA by failing to

provide for effective public involvement in the preparation of the EAs for four logging projects

In its defense, the Forest Service argued that issuing a scoping notice and releasing the final EA to

the public satisfied the mandatory public involvement requirements The court noted that while the

Regulations do not require the circulation of a draft EA, they require that the public be informed to

the extent practicable The scoping notices contained no analysis of the environmental impacts of

the projects Moreover, they failed to give the public adequate information to effectively participate

in the decision-making process.7

The Regulations are surprisingly silent when they come to providing direction for performing

an EA analysis Nonetheless, to ensure that it is adequate in substance and content, the EA must

provide an accurate, unbiased, and scientifically based study for determining the significance or

nonsignificance of potential impacts To the extent feasible, an effort should be made to quantify

and explain the probable intensity of potential impacts The results of the investigation should be

clearly documented, and the analysis should be based on professionally accepted technical and

scientific methodologies

Although the Regulations do not specifically state that an EA must consider the impacts of

con-nected, similar, or cumulative actions, it is obvious that it cannot adequately make a determination

of significance without considering them (§ 1508.27[b][7]) As illustrated by the following case, an

analysis should always consider and evaluate such impacts as appropriate

In one case, a plaintiff challenged the adequacy of an EA prepared for the importation of spent

nuclear fuel rods from Taiwan to the United States The court found the EA to be inadequate, noting

that the examination of alternatives was bound by the rule of reason and that the level of analysis

should commensurate with the severity of the impacts The court also found the agency’s choice of

alternatives and its analysis of the cumulative risks of radiation exposure to be inadequate.8

7.2.2.1 The Proposed Action

While an EIS must devote substantial consideration to each of the analyzed alternatives, the focus

of attention is predominantly on the proposed action Typically, reasonable alternatives are only

briefly described before being dismissed In these cases, the EA should clearly explain the reasons

for the dismissal of each alternative Such a practice is justified because the principal purpose of an

EA is generally distinctly different from that of an EIS While the principal purpose of an EIS is to

explore reasonable alternatives to proposed actions that could avoid or reduce significant impacts,

EAs are normally prepared to determine if an action would result in significant impacts Thus,

attention is normally focused on the proposed action with correspondingly lesser attention devoted

to the alternatives It is recommended that a sliding-scale approach be used in determining the

num-ber of alternatives as well as the degree to which the reasonable alternatives should be analyzed

7.2.2.2

The purpose of the EA is to provide decision-makers with facts about potential impacts Many EAs

have been successfully challenged because they either made or appeared to make a determination

that the impacts of a proposed action were nonsignificant.9 For this reason, precautions should be

taken to avoid any perception of such judgments made or giving the impression of partiality Any

actual judgment regarding the significance of an impact is reserved for the FONSI

Consistent with this direction, nonjudgmental terms such as consequential, inconsequential,

substantial, large, and small are generally considered acceptable Conversely, judgmental terms

such as significant, nonsignificant, acceptable, and tolerable should be avoided

While the Regulations require EISs address cumulative impacts, they are silent on this requirement

for EAs For this reason, claims have been made that analyses of cumulative impacts do not need to

be addressed in an EA However, as discussed above, it is reasonably clear that a cumulative impact

assessment (CIA) must be performed before an agency can conclusively determine that the impacts

of an action are nonsignificant (§ 1508.27[b][7])

In one case, a court found that while some individual projects had independent utility and thus

need not be considered together in the same NEPA document, the EAs prepared for each project did

not adequately consider their cumulative impacts as reasonably foreseeable actions.10

7.2.3.1 Cumulative Impact Study

A study has been carried out to determine the adequacy of cumulative impact analysis in EAs.11

This study reviewed 89 EAs prepared by 13 federal agencies that were announced in the Federal

Register during the first half of 1992 Based on certain criteria, each EA was examined to determine

if it adequately addressed cumulative impacts

Reserving Significance Findings for the FONSI

To begin with, of the 89 EAs examined, only 35 mentioned the term “cumulative impacts.”

Of these 35, 13 concluded that the cumulative impacts were insignificant without presenting any

analysis or evidence on which to base such a decision Of the remainder, 19 failed to discuss

cumulative impacts for all the resources that would be affected Of the three remaining EAs, only

two correctly identified all the past, present, and reasonably foreseeable future actions in their

analyses Table 7.2 summarizes the results of this study

Preparing a CIA that fully and rigorously satisfies the regulatory requirements set forth in 40 Code

of Federation Revolution (CFR) § 1508.7 (see Chapter 9) can be a daunting if not an impractical

task, particularly when preparing an EA As just witnessed, a close examination of CIAs in EAs

reveals that such analyses are frequently inadequate or insufficient to demonstrate that a rigorous

examination has been undertaken to prove that the cumulative impacts are nonsignificant pursuant

to regulatory requirements set forth in 40 CFR § 1508.7

NEPA is governed by the rule of reason, that is, reason should be applied when a regulatory

requirement results in an impractical, irrational, or absurd result Under some specific

circum-stances (described below), the author offers a streamlined approach referred to as the Cilix method

which provides a reasonable and practical method for demonstrating that a cumulative impact is

clearly nonsignificant.12 This technique can be used to demonstrate nonsignificance even in

situa-tions where the cumulative baseline has already sustained a significant impact

7.2.4.1 Standard Approach

Assessing cumulative impacts under the standard approach may require identifying and assessing

a potentially large array of past, present, and reasonably foreseeable future actions On a

resource-by-resource basis, analysts then need to evaluate and ‘add’ these impacts together to produce a

cumulative impact baseline In turn, the impact of the proposed action is also be ‘added’ to this

baseline If the baseline has already breached the threshold of significance, then from a strict,

absolute standpoint, any contribution beyond that point can be interpreted as significant and an EIS

would need to be prepared

7.2.4.2 Cilix Methodology

The concept behind the Cilix methodology is straightforward:

If a proposal is deemed eligible for a FONSI (i.e., the impacts are nonsignificant), the CIA need only

demonstrate that the cumulative incremental impact is clearly so small as to be negligible or

unimport-ant and therefore ‘nonsignificunimport-ant’ in terms of its contribution to the cumulative impact baseline.

TABLE 7.2

Reasons for Inadequate Cumulative Impact Analysis in EAs

Reasons for Inadequate Cumulative Impact Analysis Percentage (%)

Did not even mention cumulative impacts 61

Concluded that cumulative impacts were insignificant without presenting

any analysis of evidence

14 Failed to address cumulative impacts on all resources 21

Failed to adequately address all past, present, and reasonably foreseeable

future actions

1 Adequately addressed cumulative impacts 3

Thus, the method is applicable to proposals for which the environmental contribution, when

‘added’ to the impacts of other past, present, and reasonably foreseeable actions, is so small as to

constitute no appreciable increase in the cumulative effect Because the contribution is negligible,

it would not affect, influence, or contribute to any significant change or increase in the cumulative

impact on an environmental resource

With respect to cumulative impacts, in such instances, neither there is a rational justification to

forego the proposed action nor a rational justification for preparing an EIS A FONSI or a CATX

can thus provide an appropriate mechanism for NEPA review The significance factors (40 CFR

§ 1508.27) should be used in assessing and demonstrating that the incremental impact is trivial, but

instead of considering the significance factors from an absolute value (total impact), they can be

assessed in terms of the relative change in the impact

In essence, the Cilix method can be summarized as follows Rather than preparing what may

be highly detailed and complex assessment of a cumulative impact, the Cilix method simply

dem-onstrates that, regardless of what the cumulative baseline is, the incremental impact is too small

to have an appreciable effect upon it Therefore, the cumulative impact is nonsignificant (negative

declaration statement), consistent with the purpose of a FONSI

The beauty of the Cilix method is that one does not necessarily have to undergo an exhaustive

analysis of the environmental baseline Such an analysis is unnecessary since the proposal will have

a negligible effect on the baseline, regardless of its state This is consistent with the purpose of an

EA, since the intent of a FONSI is to demonstrate that there will be no significant impact (i.e.,

nega-tive declaration statement)

7.2.4.3 Restrictions

Application of the Cilix method is restricted to the following two circumstances:

1 Where an area has not been significantly affected, and where the direct and indirect impacts

of the proposed action are clearly so small as to have no appreciable incremental effect

2 Where an area has already sustained a significant environmental impact but the direct

and indirect impacts of the proposed action are clearly so small as to have no appreciable incremental effect

Application of the Cilix method is invalid where

the direct and indirect impacts (i.e., the incremental contribution) may result in some

appreciable incremental effect on the cumulative impact baseline

As described above, the Cilix method is restricted to cases where the incremental contribution

of the proposed action is clearly trivial or unimportant Moreover, it cannot be used in the rare

circumstance where a trivial incremental impact of a proposal could provide the final contribution

necessary to breach the threshold of significance

7.2.4.4 Application Scenarios

The following three hypothetical scenarios are presented to demonstrate the logic behind the Cilix

method as well as circumstances under which its application is valid These cases are provided for

illustrative purposes only

Case 1: Assume a situation in which a particular water resource has a water quality

environ-mental baseline (provided by considering past, present, and reasonably foreseeable future actions)

with a fictitious value of 70 units Further, assume that a federal project adds 40 units to the baseline,

resulting in a total impact of 110 units The legal (significance) limit is 100 units The cumulative

impact of the proposal would therefore breach the threshold of significance In this case, application

of the Cilix method would be invalid as the incremental impact is clearly significant, requiring the

preparation of an EIS

Case 2: Assume the same problem, but this time, using a different set of numbers to depict

significance conditions Again, the threshold of significance (maximum legal limit) is assigned

a value of 100 units But in this case, the cumulative impact baseline has already sustained a

significant impact of 110 units The proposed action would add 0.00002 units, resulting in an impact

of 110.00002 Thus, this proposal would add to the significant impact but only infinitesimally so

A strict interpretation of the CIA leads to the conclusion that once the significance threshold has

been breached, any additional impact should likewise be considered significant—clearly an

imprac-tical result in this case

Recall that NEPA is governed by the rule of reason The Cilix method provides a practical

solution to this second scenario because it considers such an increase not from an absolute value

but instead from its relative contribution, that is, the increase is so small (0.00001%) as to have no

appreciable effect on water quality In this case, the Cilix method can be used to demonstrate that

the degradation is clearly so small as to be deemed nonsignificant

Case 3: Finally, assume the same problem, but this time, using a different set of significance

conditions As with the previous cases, the threshold of significance (maximum legal limit) is

100 units Again, the environment baseline has already sustained a significant impact accruing to

110 units but in this case the proposed action would add a further 20 units, resulting in a total impact

of 130, a relatively large (18%) contribution to the environment baseline Since the Cilix method is

valid only for circumstances in which the environmental contribution is clearly nonsignificant, such

a large increase in a value that has already been significantly affected would provide a basis for a

rational decision-maker to conclude that the additional units represent a significant increase

requir-ing preparation of an EIS

7.2.4.5 Advantages

Under the Cilix method, it is not necessary to prepare what might be a highly complicated and

expensive analysis of cumulative impacts so long as the incremental impact is so trivial as to be

unimportant What is needed here is the ability to demonstrate that the incremental increase is

clearly an unimportant contribution in terms of the cumulative baseline The Cilix method is

there-fore invalid in any circumstance where this cannot be done

Beyond providing a more practical approach to the assessment of cumulative impacts in EAs,

the Cilix method has a second important advantage: Even if the cumulative impact baseline of the

applicable resource is significantly affected (or could be in the future), a FONSI can still be issued

with respect to the CIA as long as the incremental contribution from the proposed action relative to

the baseline is so small as to constitute no appreciable environmental change to the resource This is

because, from an environmental quality standpoint, it would make no practical difference whether

the proposal is implemented or not, since there would be no substantial cumulative change in the

affected environmental resources

7.2.4.6 Example

The following abbreviated example is provided for illustrative purposes only This example

dem-onstrates how the Cilix method can be applied to evaluate the cumulative impacts involved in the

proposed construction of a federal building in the crowded downtown business center of a large city

The area has already sustained a significant cumulative impact For instance, virtually all of it has

been filled with buildings and paved over with concrete The streets that run in every direction are

crowded with commuter traffic, and there is a high level of associated traffic noise Because of all

the other high-rise construction, the proposed building is practically unviewable from more than a

block away

The cumulative impact descriptions presented below assume that a rigorous analysis of the

direct and indirect impacts of the proposed building have already been performed in the EA In

addition to the CEQ’s 10 intensity factors for assessing significance, the setting (context) may also

need to be considered since the impacts of a building located in a crowded downtown area can be

quite different from those of exactly the same structure sited inside a nature preserve.13

The example described below considers two different alternatives: (1) no-action alternative and

(2) proposed action It also considers an abbreviated Cilix analysis of cumulative effects on the

following environmental resources: (1) visual quality, (2) noise, and (3) traffic congestion

Cumulative Visual Resource Impacts The following example demonstrates how the Cilix

method can be used to assess cumulative impacts on visual resources within an EA:

Alternative 1 (No-Action): As the no-action alternative would not directly result in any

measurable change in visual resources, this alternative would not contribute to any lative effect on them

cumu-Alternative 2 (Building): Existing buildings currently surround the proposed site, and future

buildings are proposed for the surrounding area Because of the limited amount of area that would be affected, the proposed construction is considered to be small-to-negligible and would therefore contribute little or no incremental increase in visual impairment when combined with other past, present, and reasonably foreseeable projects Consequently, there would be no substantial change in cumulative visual resources within the surround-ing area

Cumulative Noise Impacts The following example demonstrates how the Cilix method can be

used in an EA to assess cumulative impacts on noise:

Alternative 1 (No-Action): As the no-action alternative would not directly result in any

measurable incremental impact, this alternative would not contribute to any cumulative effect on noise levels

Alternative 2 (Building): The construction and operational noise level resulting from

exist-ing activities is deemed to be high Construction and operational noise levels associated with reasonably foreseeable projects will add to those already existing However, the incremental increase in noise level construction will be both temporary and negligible when compared with the total ambient noise level The long-term incremental increase in operational noise level will be negligible when compared to the total ambient noise level

Because the proposed project would contribute little or no incremental increase in noise when combined with other present and reasonably foreseeable projects, there would be no substantial change in cumulative noise levels within the surrounding area

Cumulative Traffic Congestion Impacts The following example demonstrates how the Cilix

method can be used in an EA to assess cumulative impacts on traffic congestion:

Alternative 1 (No-Action): As the no-action alternative would not directly result in any

mea-surable change in traffic congestion, this alternative would not contribute to any tive effect on traffic levels

cumula-Alternative 2 (Building): The traffic congestion resulting from existing construction and

operational activities is deemed to be substantial Traffic congestion impacts from ably foreseeable activities will add to the existing congestion However, the incremental increase in traffic congestion would be negligible when compared with the total current and future congestion levels Because the proposed project would contribute little or no incremental increase in traffic when combined with other present and reasonably foresee-able construction projects, there would be no substantial cumulative change in congestion levels