The Board of Adjustment for the City of Gastonia (“respondent”) appeals a judgment entered 10 May 2002 reversing the determination of respondent prohibiting Morris Communications Corporation (“petitioner”) from replacing a frame and advertisement, on one of their billboards. For the reasons stated herein, we hold respondent’s interpretation of the city code permissible but that the code is preempted by State law to the extent it conflicts, accordingly, we affirm in part, and reverse in part the judgment of the Superior Court.
Petitioner has a valid, unexpired permit for the erection and maintenance of the billboard. In January 2001, petitioner began changing the advertising sign on the billboard. After taking down the former sign-face-panel, but before replacing it with the new sign-face-panel, a zoning enforcement officer interrupted petitioner and explained that such work required a city zoning permit. Petitioner immediately applied for the permit, which was denied. Petitioner appealed, claiming changing both the frame and the advertisement were expressly permitted by North Carolina Department of Transportation (“DOT”) regulations. After a public hearing in March 2001, respondent upheld the denial of the permit finding petitioner’s actions constituted a replacement of a portion of the sign structure in violation of § 17-181 (c) of the local zoning ordinance.
Petitioner filed a writ of certiorari to the Superior Court pursuant to N.C. Gen. Stat. § 160A-388(e). The Superior Court reversed on the following bases: (1) state law preempts the city ordinance; (2) respondent committed an error of law in its interpretation of the ordinance; and (3) respondent’s decision was not supported by substantial evidence and was arbitrary and capricious. Respondent appeals.
Respondent asserts the Superior Court erred, inter alia, in: (I) its interpretation of the city zoning ordinance § 17-181(c); (II) holding state law preempts the city ordinance. Since we find the Superior *600Court correctly determined respondent committed an error of law, we need not reach respondent’s remaining assignments of error regarding the factual determinations.
“When the Superior Court grants certiorari to review a decision of the Board, it functions as an appellate court rather than.a trier of fact.” Hopkins v. Nash Cty, 149 N.C. App. 446, 447, 560 S.E.2d 592, 593-94 (2002). In reviewing a decision from a Board of Adjustment, the Superior Court must:
(1) review the record for errors of law; (2) ensure that procedures specified by law in both statute and ordinance are followed; (3) ensure that appropriate due process rights of the petitioner are protected, including the right to offer evidence, cross-examine witnesses, and inspect documents; (4) ensure that the decision is supported by competent, material, and substantial evidence in the whole record; and (5) ensure that the decision is not arbitrary and capricious.
Whiteco Outdoor Adver. v. Johnston County Bd. of Adjust., 132 N.C. App. 465, 468, 513 S.E.2d 70, 73 (1999). “When reviewing the trial court’s decision, this Court must determine: 1) whether the trial court used the correct standard of review; and, if so, 2) whether it properly applied this standard.” Hopkins, 149 N.C. App. at 447, 560 S.E.2d at 593.
The standard of review depends on the nature of the error of which the petitioner complains. If the petitioner complains that the Board’s decision was based on an error of law, the superior court should conduct a de novo review. If the petitioner complains that the decision was not supported by the evidence or was arbitrary and capricious, the superior court should apply the whole record test. The whole record test requires that the trial court examine all competent evidence to determine whether the decision was supported by substantial evidence.
Id., 149 N.C. App. at 448, 560 S.E.2d at 594 (internal citations omitted).
I. Ordinance Interpretation
[1] The first issue raised on appeal is whether, as the Superior Court found, respondent committed an error of law in its interpretation of the city zoning ordinance. Since we find no error of law, we reverse the judgment of the Superior Court.
*601“Questions involving interpretation of zoning ordinances are questions of law[,]” which we review de novo. Hayes v. Fowler, 123 N.C. App. 400, 404, 473 S.E.2d 442, 444 (1996). However, “[t]he Board [of Adjustment] is vested with reasonable discretion in interpreting the meaning of a zoning ordinance, and a court may not substitute its judgment for the board in the absence of error of law. ...” Rauseo v. New Hanover County, 118 N.C. App. 286, 289, 454 S.E.2d 698, 700 (1995).
Accordingly, we must review the Board’s interpretation of the ordinance to determine whether it is reasonable or whether an error of law exists. “The canons of statutory construction apply to the interpretation of an ordinance. . . .” Moore v. Bd. of Adjustment of City of Kinston, 113 N.C. App. 181, 182, 437 S.E.2d 536, 537 (1993) (internal citation omitted). “Unless a term is defined specifically within the ordinance in which it is referenced, it should be assigned its plain and ordinary meaning.” Ayers v. Bd. of Adjust. for Town of Robersonville, 113 N.C. App. 528, 531, 439 S.E.2d 199, 201 (1994).
Section 17-55 of the Gastonia City Code provides the following definitions:
Sign. Any object, display, or structure, or part thereof, situated outdoors, which is used to advertise, identify, display, direct, or attract attention to an object, person, institution, organization, business, product, service, event or location by any means, including words, letters, figures, design, symbols, fixtures, colors, illumination, or projected images. The term “sign” does not include the flag or emblem of any nation, organization of nations, state, political subdivision thereof, or any fraternal, religious or civic organization; works of art which in no way identify a product or business; scoreboards located on athletic fields; or religious symbols.
Sign, advertising (off-premise). A sign, other than a directional sign, which directs attention to or communicates information about a business, commodity, service, or event that exists or. is conducted, sold, offered, maintained or provided at a location other than the premises where the sign is located. Any off-premise advertising sign allowed under this chapter may display either commercial or noncommercial copy. An off-premise advertising sign shall also be known as a ‘billboard.’
Structure. A combination of materials to form a construction for use, occupancy, or ornamentation whether installed on, above, or below the surface of land or water.
*602Section 17-181 of the Gastonia City Code provides, inter alia:
(c) A nonconforming sign may not be moved or sign structure replaced except to bring the sign into complete conformity with this chapter. Once a nonconforming sign is removed (i.e., the removal of the structural appurtenances above the base or footing) from the premises or otherwise taken down or moved, said sign only may be replaced or placed back into use with a sign which is in conformance with the terms of this chapter.
(d) Minor repairs and maintenance of nonconforming signs necessary to keep a nonconforming sign in sound condition are permitted.
(f) Notwithstanding other provisions contained in this section, the message of a nonconforming sign may be changed so long as this does not create any new nonconformities.
At the public hearing, the zoning administrator asserted petitioner’s actions were more than minor repairs and changing of the message, as permitted by subsections (d) and (f). The zoning administrator contended petitioner’s actions constituted a replacement of a portion of the sign structure in violation of § 17-181(c). Respondent affirmed the zoning administrator’s interpretation.1 The Superior Court held respondent committed an error of law in its interpretation of the code, finding the term “sign” means the totality of the parts of a sign, “sign structure” means the elements necessary for the structure including the footings, poles, sign frame and sign-face-panels, and a “poster face panel”2 is not in-and-of-itself a sign or sign structure. Accordingly, the Superior Court held respondent committed an error of law in its interpretation of the statute.
*603Upon review, we do not agree respondent committed an error of law in its interpretation of the zoning ordinance. The essential term “sign structure” is not defined in the ordinance, but each individual word is broadly defined. Although the ordinance does not expressly include a list of all the parts of the “sign structure,” the broad language of the statute could reasonably be interpreted to include all those materials which form the constructed sign, including the sign frame. Moreover, section (f), which permits changing the message, could reasonably be interpreted to include only the message and not the frame. Since respondent’s interpretation is reasonable and is not the result of an error of law, we defer to their interpretation and reverse the Superior Court’s judgment.
II. Preemption
[2] Upon finding respondent’s interpretation of the statute is reasonable, we now address whether it impermissibly conflicts with, and is preempted by, State law. Accordingly, the second issue- raised on appeal is whether the Superior Court correctly held that respondent committed an error of law finding the city zoning ordinance was not preempted by State law. We review this determination de novo and find the Superior Court correctly determined the city ordinance is preempted by conflicting State regulations.
Generally, a city ordinance must be consistent with State and federal law. N.C. Gen. Stat. § 160A-174(b) (2001).
An ordinance is not consistent with State or federal law when:
(2) The ordinance makes unlawful an act, omission or condition which is expressly made lawful by State or federal law;
(5) The ordinance purports to regulate a field for which a State or federal statute clearly shows a legislative intent to provide a complete and integrated regulatory scheme to the exclusion of local regulation. . . .
N.C. Gen. Stat. § 160A-174(b) (2001).
Petitioner asserts the North Carolina’s Outdoor Advertising Control Act (“OACA”), N.C. Gen. Stat. § 136-126 to -140.1, and OACA is a “complete and integrated regulatory scheme.” Petitioner contends since the ordinance conflicts with State law, the ordinance is *604preempted pursuant to N.C. Gen. Stat. § 160A-174(b)(5). However, this Court recently determined the OACA is not a complete and integrated regulatory scheme and “conclude[d] that the OACA does not preempt local regulation of outdoor advertising.” Lamar Outdoor Advertising v. City of Hendersonville Zoning Bd., 165 N.C. App. 516, 521, 573 S.E.2d 637, 642 (2002). Although petitioner urges this Court to reject the holding in Lamar, we decline to do so because “ ‘[w]here a panel of the Court of Appeals has decided the same issue, albeit in a different case, a subsequent panel of the same court is bound by that precedent, unless it has been overturned by a higher court.’ ” State v. Roach, 145 N.C. App. 159, 161, 548 S.E.2d 841, 844 (2001) (quoting In the Matter of Appeal from Civil Penalty, 324 N.C. 373, 384, 379 S.E.2d 30, 37 (1989)). Accordingly, we are bound by this Court’s decision in Lamar and hold petitioner’s assertion is without merit.
[3] Petitioner also asserts the ordinance is preempted by State law because it conflicts with an act which has been expressly permitted by State law, in violation of N.C. Gen. Stat. § 160A-174(b)(2). Petitioner argues the DOT Regulations for Outdoor Advertising, expressly permit petitioner’s actions, and accordingly, the city ordinance prohibiting such actions are preempted.3
DOT regulation § 2E.0225 provides:
(c) Alteration to a nonconforming sign ... is prohibited. Reasonable repair and maintenance are permitted including changing the advertising message or copy. The following activities are considered to be reasonable repair and maintenance:
(1) Change of advertising message or copy on the sign face.
(2) Replacement of border and trim.
(3) Repair and replacement of a structural member, including a pole, stringer, or panel, with like material.
(4) Alterations of the dimensions of painted bulletins incidental to copy change.
19A N.C.A.C. 2E.0225(c) (2003). Both the ordinance and regulation permit changing of the advertisement message. However, the ordi*605nance prohibits replacement of any portion of the “sign structure” which respondent interprets broadly to include all structural parts of the sign. The regulation expressly permits the repair or replacement of a structural member. Accordingly, under North Carolina law, petitioner may repair or replace any structural member of the billboard, and the ordinance is preempted to the extent it conflicts. Therefore, we affirm the Superior Court’s judgment that respondent committed an error of law in failing to conclude this portion of the ordinance is preempted to the extent of the conflict.
We note the OACA requires the payment of just compensation when a “municipality, county, local or regional zoning authority, or other political subdivision . . . remove[s] or cause[s] to be removed any outdoor advertising ... for which there is in effect a valid permit issued by [DOT] . . . .” N.C. Gen. Stat. § 136-131.1 (2001). However, in the present case, the City did not “remove or cause to be removed” the sign, and accordingly this provision is inapposite.
Respondent also asserts on appeal the Superior Court erred in finding respondent’s findings of fact were not supported by substantial evidence and were arbitrary and capricious. However, we need not reach this assertion because, assuming arguendo respondent is correct, respondent found petitioner replaced a portion of the sign structure and this action is expressly permitted by DOT regulations.
In conclusion, although we find respondent’s interpretation of the city ordinance was not an error of law, we find the ordinance impermissibly conflicts with State regulations.
Affirmed in part, reversed in part.
Judge McGEE concurs.
Judge TYSON concurs in part and dissents in part in a separate opinion.