State of Minnesota, Respondent, vs. Timothy Michael Kimbro, Appellant.

may not be cited except as provided by

Minn. Stat. §480 A. 08, subd. 3 (1996).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C3-97-1314

In the Matter of the Denial

of Outdoor Advertising Device Permits

to Lakehead Outdoor Advertising, Inc.,

910 Hammond Avenue,

Superior, Wisconsin.

 Filed March 3, 1998

 Affirmed

 Toussaint, Chief Judge

 Dissenting, Forsberg, Judge[*]

 Minnesota Department of Transportation

 OAH Docket No. 71-3000-10794-2

 Frederick A. Dudderar Jr., Mark D. Pilon, Hanft, Fride, O'Brien, Harries, Swelbar & Burns, P.A., 1000 First Bank Place, 130 West Superior Street, Duluth, MN 55802-2094 (for relator Lakehead Outdoor Advertising, Inc.)

 Hubert H. Humphrey III, Attorney General, John C. Jeppesen, Bobby J. Champion, Assistant Attorneys General, 525 Park Street, Suite 200, St. Paul, MN 55103 (for respondent Commissioner, Minnesota Department of Transportation)

 William P. Dinan, Duluth City Attorney, 410 City Hall, Duluth, MN 55802 (for Amicus Curiae The City of Duluth)

 Dennis J. Peterson, Fond Du Lac Band of Lake Superior Chippewa Legal Affairs Office, 1720 Big Lake Road, Cloquet, MN 55720 (for Amicus Curiae Fond Du Lac Band of Lake Superior Chippewa)

  Considered and decided by Randall, Presiding Judge, Toussaint, Chief Judge, and Forsberg, Judge.

 U N P U B L I S H E D O P I N I O N

 TOUSSAINT, Chief Judge

The deputy county commissioner of the State Department of Transportation denied relator Lakehead Outdoor Advertising, Inc., seven advertising device permits for directional signs pertaining to casinos owned by the Fond du Lac Band of Lake Superior Chippewa (the Band). Relator challenges this decision, arguing that the Band fits within the meaning of "local governments" mandated by Minn. Stat. § 173.02, subd. 6(d) (1996). Because the statute is clear, unambiguous, and does not reference Indian tribes, we affirm.

 FACTS

Relator applied to the Minnesota Department of Transportation's (the DOT) District One office for seven directional sign permits pursuant to Minn. Stat. § 173. These signs were to indicate the mileage to the Black Bear Casino in Carlton, Minnesota, and the Fond-du-Luth Casino in Duluth, Minnesota. Three of the signs were to be located along Interstate 35 in St. Louis and Carlton Counties, two along Highway 55 in St. Louis County, one along Highway 210 in Carlton County, and one along Highway 33 in Carlton County. Because the signs were to be located in nonbusiness/industrialized zoned areas, the proposed signs had to meet the requirements for "directional signs" set forth in Minn. Stat. § 173.02, subd. 6(d).

The DOT's district permits coordinator denied the permits, reasoning that the applications "do not meet the present criteria for directional signs." Relator appealed to the DOT's external sign variance committee. The committee chairperson informed relator that the committee had reservations about the coordinator's decision and, therefore, recommended that the permits be granted.

However, the DOT's deputy commissioner rejected the committee's recommendation, reasoning that, because tribal nations consider themselves to be sovereign nations, they do not qualify as federal, state, or local government within the meaning of the statute. Relator was granted a hearing before an administrative law judge (ALJ). The ALJ agreed with the commissioner and affirmed the denial of the permits. Relator requested and received oral argument before the DOT, which affirmed the ALJ's decision.

 D E C I S I O N

This court is presented with a legal question when an agency's decision turns on the meaning of words in a statute. St. Otto's Home v. Department of Human Servs., 437 N.W.2d 35, 39 (Minn. 1989). Furthermore, this court is not bound by an agency's decision when it comes to dealing with such questions of law. Id. at 39-40.

The Minnesota Outdoor Advertising Control Act (the Act) generally prohibits erecting signs in areas adjacent to highways. Minn. Stat. § 173.01. There is, however, an exception for directional signs. Minn. Stat. § 173.08, subd. 1(a). The Act defines directional signs as:

signs containing directional information about public places owned or operated by federal, state, or local governments, or their agencies, publicly, or privately owned natural phenomena, historic, cultural, scientific, educational, and religious sites, and areas of natural scenic beauty or naturally suited for outdoor recreation, deemed to be in the interest of the traveling public.

Minn. Stat. § 173.02, subd. 6(d) (1996). Indian tribes are not mentioned in this section.

When a statute speaks for itself, the letter of the law must be followed, and there is no room for judicial construction. Green Giant Co. v. Commissioner of Revenue, 534 N.W.2d 710, 712 (Minn. 1995). Courts must give effect to the plain meaning of a statute when the language is clear and unambiguous. Id. We "cannot supply language that the legislature may have omitted or overlooked." State v. Hulst, 510 N.W.2d 262, 264 (Minn. App. 1984).

Relator argues that the Band is entitled to directional sign permits pursuant to Minn. Stat. § 173.02, subd. 6(d). We disagree. If the legislature had intended the exception to apply to Indian tribes, it would have included language to that effect. The plain meaning rule prohibits us from reading words into a statute that the legislature has omitted or overlooked. Id. Because Minn. Stat. § 173.02, subd. 6(d) does not mention tribal governments in its definition of directional signs, this court will not do so. The statute in question is not ambiguous. If relator wishes to include Indian tribes within the meaning of Minn. Stat. § 173.02, subd. 6(d), relator must seek redress from the legislature, not from this court.

In addition, none of the sign sites in question are within reservation boundaries. The locations of the signs are on land under the control of the DOT. Since this court is not ruling on whether the Band has a right to erect signs on its reservation, the Band's ability to govern itself is not called into question.

Based on our conclusion, we need not decide whether the commissioner's decision denies relator equal protection of the law, whether Indian tribes fit within the meaning of local government, or whether a casino is a public place.

  Affirmed.

 FORSBERG, Judge (dissenting),

I respectfully dissent because I consider the Band a form of local government within the meaning of Minn. Stat. § 173.02, subd. 6(d). I agree with the majority's assertion that, when the language of a statute is clear, there is no room for judicial interpretation. Green Giant Co. v. Commissioner of Revenue, 534 N.W.2d 710, 712 (Minn. 1995). I disagree, however, with the majority's conclusion that the language of the directional sign statute is clear, thereby warranting strict statutory construction. In this case, legislative intent controls whether the Band qualifies for directional sign permits.

When the language in a statute is ambiguous, it is the role of this court to "ascertain and effectuate the intention of the legislature." Stawikowski v. Collin's Elec. Co., 289 N.W.2d 390, 395 (Minn. 1979). According to Minn. Stat. § 173.02, subd. 6(d), directional signs are defined as "signs containing directional information about public places owned or operated by federal, state, or local governments, or their agencies." The term "local government," however, is not further defined in chapter 173. Thus, it is important to turn to the basic tenet of statutory interpretation, "legislative intent." It is well settled that statutes are to be interpreted as promoting, rather than defeating, the purpose of the legislature. Governmental Research Bureau, Inc. v. Borgen, 224 Minn. 313, 322, 28 N.W.2d 760, 765 (1947).

In this case, evidence of the legislature's intent comes from the statute itself, which states: "[i]t is the intention hereby to comply with the policies declared by Congress in United States Code, title 23, `Highways.'" Minn. Stat. § 173.01 (1996). According to Title XXIII, "public authority" is defined as "a Federal, State, county, town, or township, Indian Tribe, municipal or other local government * * *." 23 U.S.C. § 101 (Supp. 1997). The code also states that a `political subdivision of a State' includes an Indian Tribe." 23 U.S.C. § 402(b)(2)(i) (1996). While the directional sign statute does not contain the term "public authority," it does state that it is the intention of the legislature to comply with Title XXIII. Therefore, the language in these two code sections is relevant in discerning the intention of the Minnesota State legislature.

Furthermore, under the federal highway regulations, states are required to involve tribal governments in the statewide transportation process, to cooperate with tribal governments in matters affecting tribes, and to coordinate state transportation plans with tribes. 23 C.F.R. § 450.208(a)(23) (1996) (requiring each state to consider, analyze, and reflect on concerns of Indian tribal governments having jurisdiction over lands within boundaries of state); 23 C.F.R. § 450.214(c)(2) (1996)(requiring states to cooperate with Indian tribal governments on plans affecting area of state under jurisdiction of Indian tribal government). Once again, while these regulations deal with statewide transportational planning, they are still applicable to the present case. Since the directional sign statute does not define local government, this court must look to other sources for guidance, especially those that assist in ascertaining the intent of the legislature.

Finally, sovereign immunity supports approval of the permits. In this case, the sovereignty doctrine is relevant, not because it defines the term "local governments," but because it provides a "backdrop" against which Minn. Stat. § 173.02, subd. 6(d) must be interpreted. See McClanahan v. State Tax Comm'r of Arizona, 411 U.S. 164, 172, 93 S. Ct. 1257, 1262 (1973). Absent federal authorization, states are prohibited from diminishing any fraction of tribal sovereignty. Three Affiliated Tribes of Fort Berthold Reservation v. Wold Eng'g, 476 U.S. 877, 891, 106 S. Ct. 2305, 2313 (1986). The State of Minnesota must grant Indian reservations the same privileges it grants to other comparable governing entities:

(a) if to do so otherwise would significantly dilute the effectiveness of the governmental authority exercised, and (b) if there are no considerations of a substantial character which would justify or require denial of such equal treatment by the State of Minnesota.

 Red Lake Band of Chippewa Indians v. State of Minnesota, 248 N.W.2d 722, 725 (Minn. 1976).

Here, the commissioner's interpretation of the term "local governments" treats the Band's property as less worthy of directional signs than that of a city or county of Minnesota. In his decision, the commissioner failed to articulate any reasons justifying the denial of equal treatment by the DOT. Furthermore, the restriction on the use of directional signs for casinos owned by tribal governments intrudes on the Band's ability to govern itself according to its own laws. After all, a tribe's ability to govern itself is diluted when it is treated differently from similarly situated governments. Id. at 725 (holding to allow residents of other governmental entities certain privileges under statute while denying equal treatment to Red Lake Reservation would "dilute the effectiveness of the governing authority of the Tribal Council" and thus violate sovereign immunity). The commissioner's decision violates Minnesota's policy of recognizing tribal sovereignty because of the disparate treatment in excluding tribal governments from the term "local governments."

The Fond du Lac Band of Lake Superior Chippewa is a form of local government within the meaning of Minn. Stat. § 173.02, subd. 6(d).

The intent of the legislature is not to be defeated by placing a narrow or technical construction on words if the context and the purpose of this statute, as a whole, indicate that they were used in a popular sense with a broader meaning.

 Governmental Research Bureau, Inc., 224 Minn. at 322, 28 N.W.2d at 765. In this case, the statute at first blush is all-inclusive. The statute, by its own language, does not restrict itself to political subdivisions of the state. The statute includes publicly and privately owned natural phenomena as well as places owned by the federal government. Minn. Stat. § 173.02, subd. 6(d). Accordingly, I would reverse the commissioner's decision and grant appellants' permits for the construction and maintenance of its directional signs.

[*] Retired judge of the Minnesota Court of Appeals, serving by appointment pursuant to Minn. Const. Art VI, § 10.