In re the Marriage of: Suzanne H. Boeck, petitioner, Respondent, vs. G. Robert Boeck, Appellant.

may not be cited except as provided by

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

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C8-96-1704

Roy M. Bell,

as Trustee for the heirs and next of kin of Mary E. Bell,

deceased,

Appellant,

vs.

State Farm Mutual Automobile Insurance Company,

Respondent.

 Filed February 4, 1997

 Affirmed

 Short, Judge

Cass County District Court

File No. C396303

James R. Bettenburg, Dennis K. Kispert, 190 Midtown Commons, 2334 University Avenue, St. Paul, MN 55114 (for appellant)

Leonard J. Schweich, Askegaard & Robinson, P.A., 206 North Seventh Street, P.O. Box 826, Brainerd, MN 56401 (for respondent)

Considered and decided by Davies, Presiding Judge, Short, Judge, and Forsberg, Judge.[*]

 U N P U B L I S H E D O P I N I O N

 SHORT, Judge

In 1994, Mary E. Bell (insured) was killed when her automobile collided with a motor grader plowing snow on Highway 1 in Cass County. After settling a negligence action against the snowplow operator's commercial liability policy, Roy M. Bell (Bell), the insured's husband and trustee for her heirs, filed suit against State Farm Mutual Automobile Insurance Company (insurer), under the insured's underinsured motorist policy. Insurer moved for summary judgment, arguing its underinsured motorist policy did not cover the accident because the snowplow was not a "motor vehicle" as defined by the policy or the Minnesota no-fault automobile insurance act. The trial court granted summary judgment, finding the snowplow was "special mobile equipment" exempt from registration and did not constitute a "motor vehicle" so as to trigger underinsured motorist coverage. We affirm.

  D E C I S I O N

  On appeal from summary judgment, this court determines whether genuine issues of material fact exist and whether the trial court erred in its application of the law. State by Cooper v. French, 460 N.W.2d 2, 4 (Minn. 1990). Because the parties agree on the relevant facts, this court's function is to decide whether the trial court properly interpreted the insurance policy language in light of the facts presented. See North Star Mut. Ins. Co. v. Moon, 357 N.W.2d 95, 97 (Minn. 1984) (addressing interpretation of insurance policy as question of law where facts are undisputed). The construction of statutes presents a question of law, which we review de novo. Hibbing Educ. Ass'n v. Public Employment Relations Bd., 369 N.W.2d 527, 529 (Minn. 1985).

The Minnesota no-fault automobile insurance act mandates that no-fault insurers provide underinsured motorist coverage to protect insureds who are injured by operators of "underinsured motor vehicles." See Minn. Stat. § 65B.49, subd. 3a (1996) (requiring automobile insurance policies to include underinsured motorist coverage); Minn. Stat. § 65B.43, subd. 19 (1996) (defining underinsured motorist coverage). A vehicle may constitute a "motor vehicle" under the act only if it is subject to the registration requirements of Minn. Stat. ch. 168 (1996). Minn. Stat. § 65B.43, subd. 2 (1996); see Anderson v. St. Paul Fire & Marine Ins. Co., 427 N.W.2d 749, 751 (Minn. App. 1988) (delineating elements of statutory "motor vehicle" definition). The definition of "motor vehicle" in the insured's no-fault automobile insurance policy includes the same element. See Kashmark v. Western Ins. Cos., 344 N.W.2d 844, 846 (Minn. 1984) (noting resort to statutory definition was unnecessary where insurance policy's definition of "motor vehicle" was as broad as definition under no-fault act). Chapter 168 expressly exempts "special mobile equipment," including motor graders, from registration. Minn. Stat. §§ 168.012, subd. 3 (1996) (providing exemption); 168.011, subd. 22 (1996) (defining "special mobile equipment").

The parties do not dispute that the vehicle with which the insured's automobile collided was a "1956 Cat Model 12 Motor Grader." The plain language of chapter 168 exempts the snowplow from registration, placing the vehicle outside the policy's definition of "motor vehicle." See Minn. Stat. § 645.08(1) (1996) (requiring construction of unambiguous statute according to plain meaning of terms); Tuma v. Commissioner of Econ. Sec., 386 N.W.2d 702, 706 (Minn. 1986) (same). However, Bell argues the mounting of a wing plow on the motor grader for use in plowing snow changes the nature of the vehicle and excludes it from the statutory exemption for motor graders. We disagree. According to the manufacturer's literature, the motor grader is designed both to grade earth and to plow snow. The same manufacturer produced and marketed the wing plow specifically for use with the grader. The attachment of the wing plow did not materially alter the character of the motor grader.

Bell also argues this court's decision in Anderson, 427 N.W.2d 749, compels the conclusion that the motor grader is a "motor vehicle" under the no-fault act. However, the vehicle used as a snowplow in Anderson was a four-wheel-drive truck, upon which the operator had mounted a rotary snowblower powered by a diesel engine. 427 N.W.2d at 750. The vehicle did not fall within the "special mobile equipment" exemption, which expressly excluded "motor vehicles designed for the transportation of persons or property to which machinery has been attached." Minn. Stat. § 168.012, subd. 3 (1986) (providing exemption); Minn. Stat. § 168.011, subd. 22 (1986) (defining "special mobile equipment"); see Anderson, 427 N.W.2d at 751 (noting snowplow consisted of truck, to which snowblower had been attached). By contrast, the motor grader being used as a snowplow in this case does not fall within any exclusion from the statutory definition of "special mobile equipment," and is, moreover, expressly covered by the exemption.

Because the snowplow is exempt from the registration requirements of Minn. Stat. ch. 168, it does not constitute a "motor vehicle" under the definitions provided in the no-fault act or the insured's no-fault automobile insurance policy. Accordingly, the trial court properly granted the insurer summary judgment against Bell's underinsured motorist claim.

  Affirmed.

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