Docket No. 93978–Agenda 37–September 2002.

THE PEOPLE OF THE STATE OF ILLINOIS ex rel. JOSEPH E. BIRKETT et al., Appellees and Cross-Appellants, v. THE

								CITY OF CHICAGO, Appellant and Cross-Appellee.

Opinion filed October 18, 2002.

	JUSTICE THOMAS delivered the opinion of the court:

	Plaintiffs, Joseph E. Birkett, State’s Attorney of Du Page

County, on behalf of the People of the State of Illinois, the County

of Du Page, the Village of Bensenville, the City of Elmhurst, and

the City of Wood Dale, filed a two-count amended complaint

seeking (1) a declaration that the City of Chicago was constructing

certain improvements at O’Hare International Airport in violation

of the Illinois Aeronautics Act (Act) (620 ILCS 5/1 et seq. (West 2000)); and (2) an order enjoining the further construction of any

such improvements until such time as the City complied with the

Act. The circuit court of Du Page County entered summary

judgment in the City’s favor and denied plaintiffs’ motion for

partial summary judgment and injunctive relief. In addition, the

trial court denied the request of United States Congressman Henry

J. Hyde and State Senator James “Pate” Philip to intervene as

plaintiffs. Plaintiffs appealed, and the appellate court concluded

that entry of summary judgment in the City’s favor was erroneous.

329 Ill. App. 3d 477. We granted the City’s petition for leave to

appeal. 177 Ill. 2d R. 315(a). In addition, we allowed the

submission of several amicus curie briefs supporting both the City and plaintiffs. 155 Ill. 2d R. 345.

BACKGROUND

	Section 47 of the Act (620 ILCS 5/47 (West 2000)) prohibits

a municipality from making “any alteration or extension of an

existing airport *** for which a certificate of approval has not

been issued by the [Illinois Department of Transportation

(IDOT)].” As the owner and operator of O’Hare International

Airport, the City routinely undertakes a wide variety of projects

designed to improve airport facilities. These projects generally fall

into one of three categories: (1) “airfield” development, which includes runways, taxiways, aprons, hold pads, cargo areas,

hangars, and other areas designed to facilitate the movement of

aircraft; (2) “terminal” development, which includes terminals,

concourses, and other areas designed to facilitate the movement of

people through the airport; and (3) “landside” or “ground

transportation” development, which includes roadways, parking

facilities, mass transit, and other facilities designed to facilitate the

movement of vehicles to and from the airport terminals. The City

admits that it previously has undertaken extensive terminal and

ground transportation improvements at O’Hare without first

obtaining a certificate of approval from IDOT and that it intends

to continue undertaking such improvements in the future. These

improvements include new and renovated terminals, renovated

concourses, new and renovated roadways, and expanded parking

facilities.

	On December 22, 1995, plaintiffs filed a two-count amended

complaint against the City. Count I, an action in quo warranto, alleged that, in clear violation of section 47, the City was

undertaking substantial terminal and ground transportation

improvements at O’Hare without first obtaining a certificate of

approval from IDOT. Specifically, count I alleged that the City

“currently has under construction tens of millions of dollars of

physical alterations to [O’Hare]” and “in the past has constructed,

or plans to build several hundred million dollars of additional

construction projects at O’Hare.” Accordingly, plaintiffs sought

both a declaration that the City’s actions were without authority

and an order prohibiting the City from “constructing current and

proposed alterations at O’Hare” without first obtaining a

certificate of approval from IDOT. Count II, which was brought

specifically under the Act, incorporated all of the allegations of

count I, adding that “the intended primary purpose of much of the

recent, ongoing and planned construction at O’Hare Airport is to

incrementally expand the capacity of the airport” both to the

detriment of neighboring communities and without the approval

of IDOT. Count II sought an order prohibiting the “continued

construction of current and proposed piecemeal elements of

Chicago’s construction program at O’Hare” without first obtaining

a certificate of approval from IDOT.

	On December 16, 1996, the trial court allowed Congressman

Hyde and State Senator Philip to intervene as plaintiffs. The trial

court later vacated this decision, concluding that Congressman

Hyde and Senator Philip did not have standing to intervene.

	On June 6, 2000, the City filed a motion for summary

judgment. Plaintiffs responded with a cross-motion seeking both

partial summary judgment and an injunction against “further

physical alterations at O’Hare until these alterations are submitted

to the State for a certificate of approval, and the State has issued

a certificate of approval.” After hearing arguments and reviewing

the parties’ briefs, the trial court entered summary judgment in the

City’s favor and denied plaintiffs’ motion in its entirety. In so

ruling, the trial court explained that the phrase “any alteration or

extension of an existing airport,” as set forth in section 47, is

ambiguous. After considering both the Act as a whole and the

IDOT regulation construing section 47 (see 92 Ill. Adm. Code

§14.640 (2000)), the trial court determined that section 47 requires

IDOT certification only for those alterations and extensions that

affect “flight safety, glide path, obstruction of approaches, and

things of that matter.” Because none of the projects targeted by

plaintiffs’ complaint in any way implicated such matters, the trial

court concluded that IDOT certification for those projects was

unnecessary.

	Plaintiffs appealed, and the appellate court affirmed in part,

reversed in part, and remanded. 329 Ill. App. 3d 477. Initially, the

appellate court agreed with the trial court’s conclusion that section

47 requires IDOT certification only for those projects that impact

runways or flight patterns. 329 Ill. App. 3d at 484-85. The

appellate court then held, however, that the City may not evade

compliance with section 47’s certification requirement by

segmenting a comprehensive project that includes alterations to

runways or flight patterns into a series of smaller pieces. Thus,

because there is evidence in the record to suggest that the

contested terminal and ground transportation improvements to

O’Hare are but one component of an overall plan that includes

new or reconfigured runways, the appellate court concluded that

the entry of summary judgment in the City’s favor was erroneous.

329 Ill. App. 3d at 485. The appellate court additionally held that (1) plaintiffs were not entitled to injunctive relief; (2) federal law

does not preempt section 47’s certification requirement; and (3)

the trial court’s refusal to allow Congressman Hyde and Senator

Philip to intervene was not an abuse of discretion. 329 Ill. App. 3d

at 486-491.

ANALYSIS

	Three issues are presented for our review: (1) whether section

47 requires the City to obtain IDOT certification before

undertaking the terminal and ground transportation improvements

at issue; (2) if so, whether section 47’s certification requirement

is preempted by federal law; and (3) whether the trial court’s

refusal to allow Congressman Hyde and Senator Philip to

intervene was an abuse of discretion. Before reaching these issues,

however, we must briefly consider whether this case is appropriate

for our review at this time.

Propriety of Supreme Court Review

	Plaintiffs argue that, due to certain changes in the City’s plans

for terminal and ground transportation improvements at O’Hare,

this case presently rests upon an uncertain factual foundation and

therefore is inappropriate for review at this time. Specifically,

plaintiffs point to a series of news reports suggesting that, since

the appellate court filed its judgment in this case, the City has

announced that the World Gateway Project, which encompasses

many of the terminal and ground transportation projects at issue in

this case, may not go forward as planned. According to plaintiffs,

in light of the uncertainty concerning which, if any, portions of the

World Gateway Project remain viable, any decision by this court

at this time would be purely advisory. Plaintiffs therefore urge this

court to dismiss this appeal and remand the cause for additional

fact finding in accordance with the appellate court’s opinion.

	We decline plaintiffs’ invitation to dismiss this appeal. First,

the issue in this case has never turned upon knowing with certainty

what terminal and ground transportation improvements the City

seeks to undertake at O’Hare. Plaintiffs’ complaint did not seek to

enjoin only those terminal and ground transportation improvements at O’Hare that are part of the World Gateway

Project, nor did plaintiffs’ complaint identify with any degree of

specificity what projects they were seeking to enjoin. Rather,

plaintiffs’ complaint sought to enjoin the City from “constructing

current and proposed alterations at O’Hare,” whatever those

alterations might prove to be.

	Second, in the course of this appeal, this court allowed the

City to file an affidavit from John F. Harris, the first deputy

commissioner of the City of Chicago department of aviation. In

that affidavit, Harris testifies that, notwithstanding the World

Gateway Project’s uncertain future, the City still intends to

undertake substantial improvement projects at O’Hare without

seeking IDOT’s approval, including the construction of a new

terminal and the extension of an existing concourse. Thus, we

know with certainty that the City still intends to undertake at least

some of the improvements that plaintiffs’ complaint seeks to

enjoin.

	Finally, if plaintiffs genuinely believed that the City no longer

intends to undertake the terminal and ground transportation

improvements targeted in plaintiffs’ complaint, then plaintiffs

need only dismiss their complaint to end this litigation. The fact

that plaintiffs are instead seeking a dismissal of this appeal–and

with it the preservation of the appellate court’s decision on the

merits–suggests that plaintiffs fully expect the City to proceed

with at least some terminal and ground transportation

improvements at O’Hare. For these reasons, we decline to dismiss

this appeal.

Necessity of IDOT Certification

	The central question in this case is whether the City must

obtain IDOT certification before undertaking the terminal and

ground transportation improvements at issue. This question is one

of statutory construction, and our analysis is guided by familiar

principles.

	The fundamental rule of statutory construction is to ascertain

and give effect to the legislature’s intent. Michigan Avenue National Bank v. County of Cook, 191 Ill. 2d 493, 503-04 (2000). The best indication of legislative intent is the statutory language,

given its plain and ordinary meaning. Illinois Graphics Co. v. Nickum, 159 Ill. 2d 469, 479 (1994). Where the language is clear and unambiguous, we must apply the statute without resort to

further aids of statutory construction. Davis v. Toshiba Machine Co., America, 186 Ill. 2d 181, 184-85 (1999). If the statutory language is ambiguous, however, we may look to other sources to

ascertain the legislature’s intent. People v. Ross, 168 Ill. 2d 347, 352 (1995). A court will give substantial weight and deference to

an interpretation of an ambiguous statute by the agency charged

with administering and enforcing that statute. Bonaguro v. County Officers Electoral Board, 158 Ill. 2d 391, 398 (1994). Indeed, a reasonable construction of an ambiguous statute by the agency

charged with that statute’s enforcement, if contemporaneous,

consistent, long-continued, and in concurrence with legislative

acquiescence, creates a presumption of correctness that is only

slightly less persuasive than a judicial construction of the same act.

People ex rel. Watson v. House of Vision, 59 Ill. 2d 508, 514-15 (1974). A statute is ambiguous if it is capable of being understood

by reasonably well-informed persons in two or more different

ways. People v. Jameson, 162 Ill. 2d 282, 288 (1994). The construction of a statute is a question of law that is reviewed de novo. In re Estate of Dierkes, 191 Ill. 2d 326, 330 (2000).

	The statute at issue in this case is section 47 of the Illinois

Aeronautics Act, which states:

			“It shall be unlawful for any municipality or other

political subdivision, or officer or employee thereof, or for

any person, to make any alteration or extension of an

existing airport or restricted landing area, or to use or

operate any airport or restricted landing area, for which a

certificate of approval has not been issued by the

Department.” 620 ILCS 5/47 (West 2000).

Plaintiffs argue that section 47 unambiguously requires the City to

obtain IDOT certification before undertaking the substantial

terminal and ground transportation improvements at issue. The

City, by contrast, argues that section 47 is ambiguous because, as

plaintiffs concede, not every “alteration or extension of an existing

airport” necessitates IDOT’s approval. Instead, an alteration or extension of an existing airport must cross some threshold of

significance before IDOT certification becomes necessary, and

section 47 offers no guidance whatsoever as to when that threshold

is crossed.

	We agree with the City. As used in section 47, the phrase “any

alteration or extension of an existing airport” is ambiguous. As

both parties acknowledge, strict enforcement of the statute’s plain

language leads to patently absurd results, such as requiring IDOT

certification for the installation of a new drinking fountain or the

replacement of worn carpeting in any O’Hare facility. At the same

time, neither party disputes that the phrase “any alteration or

extension of an existing airport” includes the construction of a new

runway. The difficulty lies in discerning the point in this

continuum at which a project becomes less like a drinking fountain

and more like a runway–in other words, the point at which IDOT

certification becomes necessary. Unfortunately, the plain language

of section 47 offers no guidance on this point.

	Because strict application of the phrase “any alteration or

extension of an existing airport” leads to patently absurd results,

and because nothing in section 47 narrows the reach of this phrase,

we are compelled to look beyond section 47 for assistance in

construing this statute’s scope. Fortunately, we need not look far,

as IDOT has issued a regulation specifically construing the

ambiguous language at issue. Enacted in 1985, the regulation

provides:

		“The phrase, ‘alteration or extension’, shall include any of

the following: 	a) Any material change in the length, width or direction

of runways or landing strips;

			b) Construction or installation of any building or other

structure on the airport property which would extend

above an approach slope or a transition slope or turning

zone;

			c) Planting or permitting to grow any growth or

placement of any other obstacle on the airport property

which would extend above an approach slope or a transition slope or turning zone.” 92 Ill. Adm. Code

§14.640 (1998).

Unlike section 47, this regulation provides clear and unambiguous

guidance as to the types of improvements for which IDOT

certification is necessary. The regulation itself informs us that the

phrase “alteration or extension” includes any improvement that (1)

materially alters the length, width, or direction of a runway or

landing strips; or (2) extends above an approach slope, transition

slope, or turning zone. And established rules of statutory

construction inform us that, when a statute provides a list that is

not exclusive, as section 14.640 does (“[t]he phrase, ’alteration or

extension,’ shall include ***”), the class of unarticulated things will be interpreted as those that are similar to the named things.

Zekman v. Direct American Marketers, Inc., 182 Ill. 2d 359, 369 (1998); see also Northern Illinois Automobile Wreckers & Rebuilders Ass’n v. Dixon, 75 Ill. 2d 53, 58 (1979) (administrative rules and regulations are construed under the same standards that

govern the construction of statutes). Clearly, the common feature

of the alterations and extensions identified in section 14.640 is the

direct impact that each of them has on runway layout and/or flight

paths. Stated differently, IDOT requires certification only for those

alterations or extensions on the ground that materially alter runway

size or layout and/or interfere with or otherwise obstruct an

approach slope, transition slope, or turning zone.

	Of course, the mere fact that IDOT construes section 47 in

this manner does not end our inquiry. While courts afford

considerable deference to an agency’s interpretation of a statute

that it administers, that interpretation is not binding and will be

rejected if erroneous. Denton v. Civil Service Comm’n, 176 Ill. 2d 144, 148 (1997). That said, we conclude that IDOT’s construction

of section 47 is entirely reasonable and not the least bit erroneous.

	As noted above, section 47 is silent as to the types of

alterations or extensions that require IDOT certification. However,

in ascertaining the meaning of a statute, a court should not read

that statute in isolation but in the context of the Act as a whole.

People v. Trainor, 196 Ill. 2d 318, 322 (2001). When section 47 is considered in the context of the Act as a whole, it becomes clear that IDOT’s construction of that section is sound. Section 25 of the

Act, for example, sets forth the purpose of the Act as a whole:

			“It is hereby declared that the purpose of this Act is to

further the public interest and aeronautical progress by

providing for the protection and promotion of safety in

aeronautics; by cooperating in effecting a uniformity of

the laws relating to the development and regulation of

aeronautics in the several states; by revising existing

statutes relative to the development and regulation of

aeronautics so as to grant to a state agency such powers

and impose upon it such duties that the state may properly

perform its functions relative to aeronautics and

effectively exercise its jurisdiction over persons and

property within such jurisdiction, may assist in the

promotion of a State-wide system of airports, may

cooperate with and assist the political subdivisions of this

State and others engaged in aeronautics, and may

encourage and develop aeronautics; by establishing

uniform rules and regulations, consistent, so far as

practicable, with Federal rules and regulations, in order

that those engaged in aeronautics of every character may

so engage with the least possible restriction, consistent

with their safety and with the safety and the rights of

others; and by providing for cooperation with the Federal

authorities in the development of a national system of

civil aviation and for coordination of the aeronautical

activities of those authorities and the authorities of this

State by assisting in accomplishing the purposes of federal

legislation and eliminating costly and unnecessary

duplication of functions properly in the province of

federal agencies.” 620 ILCS 5/25 (West 2000).

Nothing in these declarations evinces any degree of legislative

concern with an airport’s terminal or ground transportation

facilities. However, phrases such as “safety in aeronautics,” “the

development and regulation of aeronautics in the several states,”

“a State-wide system of airports,” “the development of a national

system of civil aviation;,” and “eliminating costly and unnecessary

duplication of functions properly in the province of federal agencies” reveal a clear legislative interest in maintaining a safe,

uniform, and coherent system of flight patterns and air traffic.

	Similarly, section 48 of the Act, which enumerates the

standards for issuing certificates of approval under section 47,

reveals that runway layout and flight patterns–not terminal and

ground transportation facilities–are the primary legislative

priorities underlying the certification requirement:

			“In determining whether it shall issue a certificate of

approval for any airport or restricted landing area, or any

alteration or extension thereof, the Department shall take

into consideration its proposed location, size and layout,

the relationship of the proposed airport or restricted

landing area to the then current national airport plan, the

then current Federal airways system, the then current State

airport plan, and the then current State airways system,

whether there are safe areas available for expansion

purposes, whether the adjoining area is free from

obstructions based on a proper glide ratio, the nature of

the terrain, the nature of the uses to which the proposed

airport or restricted landing area will be put, the

possibilities for future development, and such other

factors as, under the circumstances, it regards as having

an important bearing thereon.” 620 ILCS 5/48 (West

2000).

Again, nothing in the preceding language reflects any degree of

legislative concern with an airport’s terminal or ground

transportation facilities. By contrast, the legislatively mandated

considerations of “the then current national airport plan, the then

current Federal airways system, the then current State airport plan,

and the then current State airways system,” “proper glide ratios,”

and “the nature of the terrain” make sense only in the context of

maintaining a safe, uniform, and coherent system of flight patterns

and air traffic. Thus, to the extent that IDOT’s interpretation of

section 47 requires certification only for those alterations or

extensions that materially alter runway size or layout and/or

interfere with or otherwise obstruct an approach slope, transition

slope, or turning zone, that interpretation dovetails perfectly with the public policy considerations identified in other relevant

portions of the Act.

	Plaintiffs maintain, however, that IDOT’s interpretation

conflicts with the definition of “airport” as set forth in section 6 of

the Act and therefore is not entitled to deference. Section defines

“airport” as:

			“any area of land, water, or both, except a restricted

landing area, which is designed for the landing and take-

off of aircraft, whether or not facilities are provided for

the shelter, servicing, or repair of aircraft, or for receiving or discharging passengers or cargo, and all appurtenant

areas used or suitable for airport buildings or other

airport facilities, and all appurtenant rights of way, whether heretofore or hereafter established.” (Emphasis

added.) 620 ILCS 5/6 (West 2000).

According to plaintiffs, section 6 specifically defines “airport” to

include terminals. Thus, if section 47 requires IDOT certification

for “any alteration or extension of an existing airport,” then IDOT certification must be required for any alteration or extension of a

terminal. Under IDOT’s interpretation, however, certification is

not required for alterations or extensions of terminals but only for those alterations or extensions that materially alter runway size or

layout and/or interfere with or otherwise obstruct an approach

slope, transition slope, or turning zone. Because IDOT’s

interpretation of section 47 defines “airport” more narrowly than

does the Act itself, plaintiffs insist that IDOT’s interpretation is

not reasonable and therefore not entitled to deference.

	Plaintiffs’ argument is flawed in two respects. First, contrary

to plaintiffs’ reading, IDOT’s interpretation of section 47 does not exempt terminal and ground transportation projects from the

certification requirement. On the contrary, IDOT interprets section

47 as requiring certification for any alteration or extension of an

existing airport that materially alters runway size or layout and/or

interferes with or otherwise obstructs an approach slope, transition

slope, or turning zone. While plaintiffs apparently believe that

only runway projects could have any of the prohibited effects, this

simply is not the case. For example, if the City set out to build a

20-story terminal facility at O’Hare, that project would be subject to IDOT certification, as it would undoubtedly interfere with an

approach slope, transition slope, or turning zone. Similarly, if a

new O’Hare access road required construction of an overpass that

would compromise an existing approach slope, that project too

would require IDOT certification. Thus, plaintiffs’ assertion that

IDOT’s interpretation of section 47 conflicts with section 6’s

definition of “airport” rests upon a fundamental misreading of

IDOT’s regulation.

	This misreading, in turn, leads to the second flaw in plaintiffs’

argument. Rather than settling the question at hand, knowing that

section 6’s definition of “airport” specifically includes terminals

merely gets us back to square one. Again, plaintiffs concede that

not every alteration or extension of an existing airport–including

alterations to existing terminals–requires IDOT certification. Thus,

knowing that the Act’s definition of “airport” specifically includes

terminals tells us nothing, as the critical question remains: What types of alterations or expansions to an existing airport require certification? IDOT’s interpretation of section 47 answers this

question quite reasonably, requiring certification only for those

alterations or extensions–whether to runways, terminals, ground

transportation facilities, or whatever–that materially alter runway

size or layout and/or interfere with or otherwise obstruct an

approach slope, transition slope, or turning zone.

	Finally, we note that IDOT’s interpretation of “alteration or

extension of an existing airport,” as set forth in section 14.640, has

remained on the books continuously and unaltered since 1985.

More importantly, although the General Assembly has enacted

numerous amendments to the Act since section 14.640 was issued

in 1985 (see, e.g., Pub. Act 84–1473, eff. January 26, 1987; Pub. Act 87–232, eff. September 3, 1991; Pub. Act 89–345, eff. January

1, 1996; Pub. Act 91–712, eff. July 1, 2000), sections 47 and 48 of

the Act have remained perfectly intact. In fact, sections 47 and 48

read exactly the same today as when originally enacted in 1945. As

this court explained almost 50 years ago:

		“That the statute has remained unaltered through

successive sessions of the General Assembly ***

indicates legislative acquiescence in the contemporary and continuous administrative interpretation.” People ex rel. Spiegel v. Lyons, 1 Ill. 2d 409, 414 (1953).

Here, IDOT’s construction of section 47 has stood undisturbed by

legislative intervention for more than 17 years, a clear indication

that the General Assembly fully acquiesces in that construction.

	In sum, as used in section 47, the phrase “any alteration or

extension of an existing airport” is ambiguous. IDOT, the agency

charged by the General Assembly with the enforcement of that

section, has issued a regulation specifically construing the

ambiguity at issue. IDOT’s interpretation is reasonable on its face,

consistent with related portions of the Act, and has been in force

continuously for more than 17 years without any intervention from

the legislature. In light of these facts, we choose to defer to

IDOT’s construction of section 47, which requires certificates of

approval only for those alterations or extensions that materially

alter runway size or layout and/or interfere with or otherwise

obstruct an approach slope, transition slope, or turning zone.

	Having concluded that IDOT’s interpretation of section 47 is

reasonable and entitled to deference, we now must decide whether

the trial court properly entered summary judgment in the City’s

favor. We hold that it did.

	Summary judgment is proper where, when viewed in the light

most favorable to the nonmoving party, the pleadings, depositions,

admissions, and affidavits on file reveal that there is no genuine

issue as to any material fact and that the moving party is entitled

to judgment as a matter of law. 735 ILCS 5/2–1005(c) (West

2000); Ragan v. Columbia Mutual Insurance Co., 183 Ill. 2d 342, 349 (1998). Like the construction of a statute, the entry of

summary judgment is a question of law that is reviewed de novo. Ragan, 183 Ill. 2d at 349.

	Plaintiffs’ complaint raises one central issue–whether the City

must obtain IDOT certification before undertaking the substantial

terminal and ground transportation improvements at issue. As to

this issue, no genuine issue of material fact exists, and the City

unquestionably is entitled to judgment as a matter of law.

Plaintiffs do not argue, and there is nothing in the record to

suggest, that the City’s proposed terminal and ground transportation improvements themselves will either materially alter runway size or layout and/or interfere with or otherwise obstruct

an approach slope, transition slope, or turning zone. On the contrary, plaintiffs’ position throughout this litigation has been

that IDOT certification is required because the proposed terminal

and ground transportation improvements are part of a larger plan that ultimately will include material changes in O’Hare’s runway

configuration. And while the City concedes that plaintiffs’

characterization of the City’s long-term plan for O’Hare is

accurate, our analysis of section 47 demonstrates that the City’s

long-term plan for O’Hare is irrelevant to the question of whether

IDOT certification is required for the improvements at issue.

Again, the only relevant question under section 47 is whether the

proposed improvements themselves will either materially alter

runway size or layout and/or interfere with or otherwise obstruct

an approach slope, transition slope, or turning zone. Nothing in the

record suggests that any of the proposed improvements will have

that effect, and the circuit court therefore properly entered

summary judgment in the City’s favor.

	In reaching this result, we necessarily reject the appellate

court’s theory of segmentation, which formed the basis for its

determination that a remand for additional fact finding was

necessary. Under the appellate court’s analysis, although the City

is required to obtain IDOT certification only for those projects that

either materially alter runway size or layout and/or interfere with

or otherwise obstruct an approach slope, transition slope, or

turning zone, the City “cannot evade statutory requirements by

segmenting an overall project into smaller pieces.” 329 Ill. App.

3d at 485. Thus, because there is evidence in the record suggesting

that the proposed terminal and ground transportation

improvements are but one component of a larger plan that also

includes new or reconfigured runways, the appellate court

concluded the entry of summary judgment was erroneous.

	Although we have no quarrel with the appellate court’s

characterization of the evidentiary record in this case, we

nevertheless must reject the appellate court’s analysis, as it rests

upon a faulty premise, namely, that by segmenting the O’Hare

expansion project into a series of smaller projects, the City somehow could evade IDOT certification for material changes to

O’Hare’s runway system or improvements that obstruct or

otherwise interfere with an approach slope, transition slope, or

turning zone. One simply does not follow from the other. Assume,

for example, that the City undertakes every conceivable terminal

and ground transportation improvement–e.g., a new terminal, new parking facilities, new rail service, and new western expressway

access–and that all of these projects are explicitly undertaken with

runway expansion in mind. The City still would have to obtain IDOT certification before initiating the actual runway expansion.

And IDOT still would have to assess the propriety of the proposed runway expansion in light of the factors set forth in any relevant

portions of the Act and/or IDOT regulations. And, on

administrative review, this state’s courts still would have to review the propriety of IDOT’s determination solely in light of the

relevant legal and statutory standards. Simply put, and contrary to

the appellate court’s analysis, nothing that the City undertakes in anticipation of new or expanded runways can relieve the City of its obligation to obtain IDOT certification for the construction of new or expanded runways.

	As a final note on the question of IDOT certification, we wish

only to direct the City’s attention to the counsel offered by the

circuit court upon the entry of summary judgment in the City’s

favor:

			“In making these findings the Court will note that any

construction that is made by the City of Chicago it

undertakes at its peril unless and until the certificate is

received from the Department of Transportation ***. The

issue of runways is not before the court and is not

germane. So, in short, if the City goes ahead and builds

and doesn’t ultimately get a certificate of approval for

extending runways or doesn’t apply for one, then that is

the concern only of the City of Chicago.”

Preemption

	In light of our conclusion that IDOT certification is

unnecessary for the proposed terminal and ground transportation improvements at issue in this case, we need not decide whether

section 47’s certification requirement is preempted by federal law.

Dismissal of Intervening Plaintiffs

	The final issue is whether the trial court erred in vacating its

decision to allow U.S.nited States Congressman Henry J. Hyde and

State Senator James “Pate” Philip to intervene as plaintiffs in this

litigation. We hold that it did not.

	Intervention in civil proceedings is governed by section 2–408

of the Code of Civil Procedure (735 ILCS 5/2–408 (West 2000)),

which provides in relevant part:

			“(a) Upon timely application anyone shall be permitted

as of right to intervene in an action: (1) when a statute

confers an unconditional right to intervene; or (2) when

the representation of the applicant’s interest by existing

parties is or may be inadequate and the applicant will or

may be bound by an order or judgment in the action; or

(3) when the applicant is so situated as to be adversely

affected by a distribution or other disposition of property

in the custody or subject to the control or disposition of

the court or a court officer.

			(b) Upon timely application anyone may in the

discretion of the court be permitted to intervene in an

action: (1) when a statute confers a conditional right to

intervene; or (2) when an applicant’s claim or defense and

the main action have a question of law or fact in

common.” 735 ILCS 5/2–408(a), (b) (West 2000).

The purpose of this section is to liberalize the practice of

intervention so as to avoid, upon timely application, the

relitigation of issues in a second suit which were being litigated in

a pending action. Caterpillar Tractor Co. v. Lenckos, 84 Ill. 2d 102, 111-12 (1981). Although a party need not have a direct

interest in the pending suit, it must have an interest greater than

that of the general public, so that the party may stand to gain or

lose by the direct legal operation and effect of a judgment in the

suit. Caterpillar Tractor Co., 84 Ill. 2d at 112. The decision to allow or deny intervention, whether permissively or as of right, is a matter of sound judicial discretion that will not be reversed

absent an abuse of that discretion. In re Application of the County Collector of Du Page County  Collector for Judgment for Delinquent Taxes

for the Year 1992, 181 Ill. 2d 237, 2487 (1998).

	Here, we find no basis for reversing the trial court’s decision

denying Congressman Hyde and Senator Philip’s request to

intervene. First, Congressman Hyde and Senator Philip have failed

to identify any statute that either conditionally or unconditionally

confers upon them a right to intervene in this litigation. Although

they point to section 33 of the Act, that section applies only to

“State, county and municipal officer[s] charged with the

enforcement of State and municipal laws.” (Emphasis added.) 620 ILCS 5/33 (West 2000). As members of the legislative branch,

Congressman Hyde and Senator Philip are not charged with the

enforcement of Sstate or municipal laws. Consequently, section 33

does not apply to them. Second, Congressman Hyde and Senator

Philip argue that they should have been allowed to intervene

because they “are both residents of the communities adjacent to

O’Hare,” “are personally affected by noise and air pollution from

O’Hare,” and “have personal interests in the welfare of the

constituencies they represent.” While we have no reason to doubt

any of these assertions, Congressman Hyde and Senator Philip

overlook the fact that State’s Attorney Birkett filed this action on

behalf of the citizens of Du Page County, including Congressman

Hyde, Senator Philip, and all of their respective constituents. More

importantly, Congressman Hyde and Senator Philip do not

anywhere suggest that State’s Attorney Birkett’s representation of

their interests may prove inadequate or that their interests do not

coincide with those of Birkett or any of the other named plaintiffs.

	In light of the forgoing, we conclude that the trial court’s

denial of Congressman Hyde and Senator Philip’s request to

intervene was not an abuse discretion.

CONCLUSION

	For the foregoing reasons, the judgment of the appellate court

is affirmed in part and reversed in part, and the judgment of the

circuit court is affirmed.

Appellate court judgment affirmed

in part and reversed in part;

circuit court judgment affirmed.