Buckley Powder Co. (Buckley) brought suit on behalf of itself and others alleging that the State's motor vehicle registration and tax statutes as amended in 1989 and 1990 violated the commerce clause and seeking injunctive and declaratory relief and refunds of the allegedly improperly collected taxes. Because our intervening decision in Riverton Produce Co. v. State, 871 P.2d 1213 (Colo. 1994), rendered Buckley's claims for injunctive and declaratory relief moot, certification of a class under C.R.C.P. 23 (b)(2) is likewise mooted. Thus, we reverse that part of the court of appeals' decision directing the trial court to consider class certification under C.R.C.P. 23(b)(2).

It has long been established that the Commerce Clause of the United States Constitution not only grants Congress the authority to regulate commerce among the several states, but also limits the power of the states to discriminate against interstate commerce. Riverton Produce Co. v. State, 871 P.2d 1213 (Colo. 1994). This latter limitation on the states is characterized as the "negative" aspect of the Commerce Clause and prohibits "economic protectionism — that is, regulatory measures designed to benefit in-state economic interests by burdening out-of-state competitors."

Colorado state courts can and do grant relief in cases challenging the constitutionality of tax measures. See Riverton Produce Co. v. State, 871 P.2d 1213, 1230 (Colo.1994) (en banc). Further, Colorado courts have considered Commerce Clause challenges involving taxes.

In considering a motion to dismiss, we must take the facts in the light most favorable to the Successor Corporation as the non-moving party. Under the IRP, the state in which a motor carrier's primary headquarters are located bills, collects and pays to all taxing authorities of other states all IRP fees. The IRP fees are apportioned based on actual miles traveled by the motor carrier in each jurisdiction during the preceding registration year (April through March). Complaint at ¶ 12. See also Riverton Produce Co. v. State of Colorado, 871 P.2d 1213, 1217, n. 6 (Colo. 1994), citing American Trucking Assns., Inc. v. Scheiner, 483 U.S. 266, 271-73, 107 S.Ct. 2829, 2834, 97 L.Ed.2d 226 (1987). The "International Registration Plan" is defined in 49 U.S.C. § 31701(4) as "the interstate agreement on apportioning vehicle registration fees paid by motor carriers, developed by the American Association of Motor Vehicle Administrators".

Thus, severing portions of a statute is preferred over invalidating the entire statute unless the invalid statutory provisions are so “pervasive or inextricably intertwined with” the valid provisions that severance would render the statute incomplete. See Riverton Produce Co. v. State, 871 P.2d 1213, 1226 (Colo.1994) ; see also Hejira Corp. v. MacFarlane, 660 F.2d 1356, 1362 (10th Cir.1981) (applying Colorado's general severability clause and explaining that severance “is impossible if the court determines that the valid provisions, standing alone, are incomplete and are incapable of being executed in accordance with legislative intent”). When deciding whether we can sever unconstitutional provisions from an otherwise valid statute, we consider two factors: (1) the autonomy of the statutory portions that remain after the defective provisions are excised; and (2) the intent of the enacting legislative body.

02(j) options in isolation makes no practical sense, because the Associations do not seriously claim that any of their members is somehow forced, or is likely, to choose the (j)(1) District-registration option over the less expensive (j)(2) apportioned-registration option, or to choose the (j)(3) trip permit option if it is more costly than a different option.See also Riverton Produce Co. v. State, 871 P.2d 1213, 1222 (Colo. 1994) ("Where application of a state tax is alleged to violate the Commerce Clause, it `must be assessed in light of its actual effect considered in conjunction with other provisions of the State's tax scheme.' . . . Thus, the question before us is not whether application of [the challenged legislation] to interstate carriers but not intrastate carriers, by itself, would have violated the Commerce Clause, but rather whether the State's efforts as a whole to implement that statute in 1990 amounted to unconstitutional discrimination." (quoting Maryland v. Louisiana, 451 U.S. 725, 756, 101 S.Ct. 2114, 68 L.Ed.2d 576 (1981))); Alaska v. Arctic Maid, 366 U.S. 199, 204-05, 81 S.Ct. 929, 6 L.Ed.2d 227 (1961) (holding that 4% tax on foreigners who catch salmon in state waters and ship them south to be canned was permissible because domestic canneries were already subject to 6% tax); Am. Trucking Ass'ns v. Quinn, 437 A.2d 623, 626-27 (Me. 1981) (noting that Maine had entered into a registration reci

However, the district court denied the Department's motion for attorney fees and costs, stating that attorney fees were not appropriate since Golden's proceeded in district court with a "good-faith belief" that the district court possessed jurisdiction over its claims. The delay between the filing of the complaint and the dismissal occurred because the district court held this case in abeyance until entry of this court's final determination in Riverton Produce Co. v. State, 871 P.2d 1213 (Colo. 1994), which challenged the State's application of the new vehicle registration scheme first to interstate carriers, and then, through the process of backbilling, to intrastate carriers. In Riverton, we held that the State's application of Senate Bill 159 did not unconstitutionally discriminate against interstate commerce.

The Division of Local Government also has interpreted the statute as permitting use of specific ownership tax revenues for this purpose. Indeed, we recognized in Riverton Produce Co. v. State, 871 P.2d 1213, 1228 (Colo. 1994), the use of specific ownership taxes to fund road and bridge projects. Located within the Department of Local Affairs, the Division of Local Government gives assistance to local governments and is authorized among other things to conduct research on local government financial issues.

Furthermore, "`[a]s a general rule if a statute is constitutional in one part and unconstitutional in another, the constitutional provision may be sustained and the unconstitutional stricken.'" Riverton Produce Co. v. State of Colorado, 871 P.2d 1213, 1226 (Colo. 1994) (citing City of Lakewood v. Colfax Unlimited Ass'n, Inc., 634 P.2d 52, 70 (Colo. 1981)).

Also, because Tuscany did not prevail on appeal, its request for appellate attorney fees and costs must be denied. See Riverton Produce Co. v. State, 871 P.2d 1213 (Colo. 1994). Accordingly, we reverse the trial court's orders awarding costs and attorney fees to Tuscany and BCORP, and remand for determination of Western States' costs and reasonable attorney fees and an allocation of that award between Tuscany and BCORP.