FAY, Circuit Judge:

This is an appeal from an adverse summary judgment ruling, in which the district court refused to declare O.C.G.A. § 33-34-5(b) (1982) (the Georgia No-Fault Act) unconstitutional on due process, equal protection and other constitutional grounds. We affirm. Although appellant's argument is extremely persuasive, after full consideration, we conclude that we should not use the statute's "tortured history" of interpretation in the Georgia courts as a basis for holding it unconstitutional.

A. COLLATERAL ESTOPPEL

As an initial matter, we must dispose of the question, raised by the appellee State of Georgia for the first time at oral argument, of whether appellant is collaterally estopped from raising these constitutional objections to the No-Fault Act. Appellee grounds this objection on the fact that appellant had raised almost identical arguments in prior litigation before the Georgia courts, and those issues were decided adversely to the appellant. See Cotton States Mutual Insurance Co. v. McFather, 251 Ga. 739, 741, 309 S.E.2d 799, 801-02 (1983) (hereinafter McFather). Although appellee's collateral estoppel argument is a formidable one, we will exercise the discretion available to us, see Parklane Hosiery Co. v. Shore, 439 U.S. 322, 331, 99 S.Ct. 645, 651, 58 L.Ed.2d 552 (1979), and reach the merits of this case.

We recognize that appellee did not raise this issue at the trial level; nevertheless we also recognize that appellee was unable to do so because of the parallel progression of the two cases in which the constitutional objections were made. The parties at bar filed their briefs in the instant case prior to the time that the state court decision, which held adversely to appellant on the constitutional claims, was issued. Under these circumstances, we hold that the collateral estoppel issue, though not raised in the district court, was not waived.

Collateral estoppel is properly invoked "if the issue in the subsequent proceeding is identical to the one involved in the prior action, the issue was actually litigated, and the determination of the issue was necessary in the prior action." Williams v. Bennett, 689 F.2d 1370, 1381 (11th Cir. 1982) (upholding the offensive use of collateral estoppel with regard to constitutional claims). It is clear that these three criteria are met in the case at bar. The constitutional issues raised in the McFather litigation were virtually identical to those raised in the instant case. Though the Georgia Supreme Court's treatment of those issues was admittedly cursory, they were specifically addressed and decided by that court. Furthermore, a litigant may assert collateral estoppel, though he was not a party to the prior suit. Bank of Heflin v. Landmark Inns, 604 F.2d 354 (5th Cir. 1979). Therefore, the State of Georgia is free to invoke collateral estoppel offensively against appellant.

The offensive use of collateral estoppel raises particular judicial concerns; it is governed by slightly different principles than the historic defensive use of the issue preclusion claim. See Nations v. Sun Oil Co., 705 F.2d 742, 744 (5th Cir. 1983) ("Collateral estoppel is an equitable doctrine. Offensive collateral estoppel is even a cut above that in the scale of equitable values."); Johnson v. United States, 576 F.2d 606, 614 (5th Cir. 1978), cert. denied, 451 U.S. 1018, 101 S.Ct. 3007, 69 L.Ed.2d 389 (1981). The Supreme Court has only recently approved the offensive use of collateral estoppel. Parklane Hosiery Co. v. Shore, 439 U.S. 322, 99 S.Ct. 645, 58 L.Ed.2d 522 (1979). Moreover, the Court has cautioned that fairness to both parties must be considered when it is applied. Id. at 331, 99 S.Ct. at 651. Of primary importance is whether the opposing party had an adequate incentive to litigate vigorously in the previous proceedings and whether he received a full and fair hearing in that proceeding.

Once, however, the litigant has had a full and fair opportunity to litigate his claim, the trial court has broad discretion in deciding whether offensive collateral estoppel is appropriate. See Parklane Hosiery, 439 U.S. at 331, 99 S.Ct. at 651. The Supreme Court has recently reaffirmed that collateral estoppel promotes "the comity between state and federal courts that has been recognized as a bulwark of the federal system." Allen v. McCurry, 449 U.S. 90, 95-6, 101 S.Ct. 411, 415, 66 L.Ed.2d 308 (1980). The principles of federalism and comity are implicated in the instant case. Appellant is urging the federal courts to declare the state statute unconstitutional (by federal standards) because the state courts have experienced difficulty in their interpretations. At least in the context of civil rights suits, the Supreme Court has stated that Congress did not intend "to allow relitigation of federal issues decided after a full and fair hearing in a state court simply because the state court's decision may have been erroneous." Id. at 101, 101 S.Ct. at 418. Therefore, the confusing interpretations given this statute by the state courts should not be a basis for denying the preclusive effect of collateral estoppel.

However, the Supreme Court has also noted that preclusion may be inappropriate, particularly in constitutional adjudication, when issues of law arise in successive actions. Montana v. United States, 440 U.S. 147, 160-63, 99 S.Ct. 970, 977-78, 59 L.Ed.2d 210 (1979). In addition, special difficulties arise when precluding a party who did not have the initiative in the prior action. See Johnson, 576 F.2d at 614. Moreover, this circuit has recently noted that the discretion used when determining if preclusion is appropriate is not unlimited. Abuse of that discretion will result if "there is a significant likelihood of substantial unfairness" to the parties if preclusion is applied. Deweese v. Town of Palm Beach, 688 F.2d 731, 734 (11th Cir. 1982). The likelihood of unfairness increases when conflicting rulings involve the same defendant.

Adopting this broad discretion as our own standard in determining the collateral estoppel question, we decide not to apply collateral estoppel in the instant case. In light of the unique history of the statute challenged here and the important principles of federalism involved when a federal court is asked to determine the constitutionality of a state statute, we proceed to the merits of this case.

B. CONSTITUTIONAL CHALLENGES TO STATE STATUTES

Federal courts must be slow to declare state statutes unconstitutional, see Ford v. Strickland, 676 F.2d 434, 442 (11th Cir. 1982) ("[W]e do not sit to question [the state supreme court's] interpretation of that state's statutes"), and they must be especially slow to do so on the ground of the state courts' inability to consistently interpret their own statutes. It is well-settled that "[s]tate courts have the right to construe their own statutes," Bank of Heflin v. Miles, 621 F.2d 108, 113 (5th Cir. 1980), and federal courts are bound by that state interpretation. Id. at 114. See also Sanchez v. United States, 696 F.2d 213, 216 (2d Cir. 1982) ("To comply with the principle of comity which undergirds our federal system, we are obliged to give full effect to decisions of New York's highest court on issues involving the application of New York law."). When ruling upon the constitutionality of a state statute, a federal court "may only consider the statute's plain meaning and authoritative state court constructions of the statute." Florida Businessmen v. State of Florida, 499 F. Supp. 346, 352 (N.D.Fla. 1980).

With this limited scope of review in mind, we now turn to the statute challenged in the instant case. The No-Fault Act, prior to its amendment in 1982, provided that:

Each application for a policy of motor vehicle liability insurance sold in this state must contain separate spaces for the insured to indicate his acceptance or rejection of each of the optional coverages listed in subsection (2) of this Code section and no such policy shall be issued in this state unless these spaces are completed and signed by the prospective insured.

O.C.G.A. § 33-34-5(b).

The litigation over this statute exists because of conflicting interpretations as to what burden the statute imposes on no-fault insurers to obtain specific acceptance or rejection of optional coverage from each applicant. We note initially that the No-Fault Act is facially constitutional. See Erznoznik v. City of Jacksonville, 422 U.S. 205, 216, 95 S.Ct. 2268, 2276, 45 L.Ed.2d 125 (1974) ("[A] state statute should not be deemed facially invalid unless it is not readily subject to a narrowing construction by the state courts. . . ."). See also Sawyer v. Sandstrom, 615 F.2d 311, 315 (5th Cir. 1980). The Supreme Court has stated that "[i]n evaluating a facial challenge to a state law, a federal court must, of course, consider any limiting construction that a state court ... has proffered." Hoffman Estates v. Flipside, 455 U.S. 489, 494 n. 5, 102 S.Ct. 1186, 1191 n. 5, 71 L.Ed.2d 362 (1982). The Georgia Supreme Court has recently attempted to clarify its position as to the meaning of the statute. See Flewellan [Flewellen] v. Atlanta Casualty Co., 250 Ga. 709, 300 S.E.2d 673 (1983).

A brief description of the history of the Georgia courts' attempts to interpret the No-Fault Act illustrates the confusion the statute has wrought. The No-Fault Act's tortured history originated with the Georgia Court of Appeals' decision in Jones v. State Farm Mutual Auto Insurance Co., 156 Ga. App. 230, 274 S.E.2d 623 (1980), cert. dismissed, 248 Ga. 46, 280 S.E.2d 837 (1981) (hereinafter "Jones"). (Certiorari was initially granted in Jones, but then dismissed by the Georgia Supreme Court as improvidently granted.) Jones interpreted the No-Fault Act to require multiple signature lines on applications to indicate acceptance or rejection of optional personal injury protection (PIP) coverage. On December 1, 1982, the Georgia Court of Appeals, en banc, overruled Jones. Atlanta Casualty Co. v. Flewellen, 164 Ga. App. 885, 300 S.E.2d 166 (1982). In the Flewellen decision, the Court of Appeals stated that "to require a separate and repetitive signature by each subspace defies the rules of logic and reason and blindly applies a rule of literalness." Id. at 888, 300 S.E.2d at 169. Shortly thereafter, however, the Georgia Supreme Court, having granted certiorari sua sponte, reversed the Court of Appeals. In that decision, the court held that two signature lines, one indicating acceptance or rejection of optional PIP and another to indicate acceptance or rejection of vehicle damage coverage, would meet the statutory requirements. Flewellen v. Atlanta Casualty Co., 250 Ga. 709, 711, 300 S.E.2d 673, 676 (1983). Since the Flewellen decision, the Georgia Supreme Court has held that substantial compliance is sufficient to meet the statutory requirements. St. Paul Fire Marine Insurance Co. v. Nixon, 252 Ga. 469, 314 S.E.2d 215 (1984). However, if the information regarding optional PIP coverage is contained in a small square in an abbreviated form, then the insurance application will not meet the substantial compliance test. Tolison v. Georgia Farm Bureau Mutual Insurance Co., 253 Ga. 97, 317 S.E.2d 185 (1984).

Given the background of this confused judicial history, we now turn to the constitutional objections raised by appellant. Two basic constitutional arguments are made. First, appellant contends that the statute is unconstitutionally vague, and therefore constitutes a denial of its procedural due process rights. Second, appellant contends that the penalties and punitive damages provisions of the No-Fault Act contravene its due process and equal protection rights.

1. Void for Vagueness

Undoubtedly, appellant's strongest argument is that the statute is unconstitutionally vague. There is no question that the Georgia courts have found the No-Fault Act difficult to interpret. However, the standard of review with regard to commercial statutes is a very lenient one. Such statutes are impermissibly vague only if they provide "`no rule or standard at all.'" Exxon Corp. v. Busbee, 644 F.2d 1030, 1033 (5th Cir.), cert. denied, 454 U.S. 932, 102 S.Ct. 430, 70 L.Ed.2d 239 (1981) (quoting A.B. Small Co. v. American Sugar Refining Co., 267 U.S. 233, 239, 45 S.Ct. 295, 297, 69 L.Ed. 589 (1925)). "Uncertainty . . . is not enough for [the commercial regulatory statute] to be unconstitutionally vague; rather, it must be substantially incomprehensible." Id. at 1033. Though appellant urges us to adopt a more stringent standard of review, we decline to do so. We hold that under the standard set forth in Exxon Corp. v. Busbee, the statute passes constitutional muster.

2. Equal Protection

As with a due process challenge to a commercial regulatory statute, an equal protection challenge is accorded minimal scrutiny. See Minnesota v. Clover Leaf Creamery Co., 449 U.S. 456, 101 S.Ct. 715, 66 L.Ed.2d 659 (1981). Only a "wholly arbitrary act" can not withstand an equal protection challenge to an economic regulatory statute. New Orleans v. Dukes, 427 U.S. 297, 303-04, 96 S.Ct. 2513, 2516-17, 49 L.Ed.2d 511 (1976) (per curiam). See also Minnesota v. Cloverleaf, 449 U.S. at 464, 101 S.Ct. at 723 (parties asserting an irrational classification may not prevail "so long as the question is debatable"). Appellant asserts that the No-Fault Act violates the equal protection rights of no-fault insurers. However, this constitutional challenge must be evaluated under this deferential standard.

The penalty provisions built-in to the No-Fault Act clearly bear a rational relationship to the legislature's dual purpose of encouraging prompt payment and avoiding litigation over no-fault claims. In light of the fact that state legislatures are given wide latitude in the regulation of commercial interests, New Motor Vehicle Board of California v. Orrin W. Fox Co., 439 U.S. 96, 107, 99 S.Ct. 403, 410, 58 L.Ed.2d 361 (1978), the No-Fault Act passes constitutional muster.

Accordingly, the district court's order granting summary judgment in favor of appellee is AFFIRMED.