State appeals from a trial court order that declared SDCL 32-23-10 unconstitutional and suppressed the test results of a blood sample taken from Defendant, Jerold J. Heinrich.
Facts
On August 17, 1988, South Dakota Highway Patrol Trooper Jeff Lanning observed Heinrich’s vehicle weave off the edge of the road and then cross the center line. Lanning stopped Heinrich’s vehicle. After observing Heinrich and conducting field sobriety tests, Lanning placed Heinrich under arrest for driving while under the influence of an alcoholic beverage in violation of SDCL 32-23-1.1 Lanning then requested a records check through State Radio Communications and was informed that Heinrich had two prior convictions in the last five years for driving while under the influence. As a result, Heinrich was not given the option of refusing the blood test because Lanning received information that Heinrich was being arrested for a third violation of SDCL 32-23-1, and SDCL 32-23-10 revokes the right to refuse to submit to a blood alcohol test after two violations of SDCL 32-23-1.2 Lanning did read the standard implied consent card to Heinrich, however, and informed him of his implied consent rights.
Lanning took Heinrich to a local hospital where a sample of Heinrich’s blood was obtained, showing a blood alcohol concentration of .293 percent by weight. Heinrich was subsequently charged with a violation of SDCL 32-23-1(1), driving with .10 percent, or more, by weight of alcohol in the blood, and a violation of SDCL 32-23-1(2), driving while under the influence of an alcoholic beverage. He was also charged under the penalty enhancement provision of SDCL 32-23-4.
Heinrich moved to suppress the blood test results, claiming that the non-consensual taking of his blood violated his constitutional rights. The trial court granted the motion and suppressed the test results, concluding that SDCL 32-23-10 was unconstitutional because it violated the separation of powers doctrine. The trial court reasoned that the statute required a trooper to make a final decision regarding the validity of prior convictions, and such a decision is properly a judicial determination. The trial court concluded that such a situation “improperly vests judicial power in an executive officer, which is clearly forbidden under the separation of powers doctrine.” State appeals following our order permitting an appeal from an intermediate order. We reverse and remand for trial.
Decision
A state may force an individual suspected of driving while intoxicated to submit to a blood alcohol test. Schmerber v. California, 384 U.S. 757, 86 S.Ct. 1826, 16 L.Ed.2d 908 (1966); see also South Dakota v. Neville, 459 U.S. 553, 103 S.Ct. 916, *2774 L.Ed.2d 748 (1983). Withdrawal of a blood sample for such a test may be required provided it is 1) incident to a lawful arrest, 2) taken by a reliable and accepted method, 3) in a medically approved, reasonable manner, and 4) with probable cause to believe the evidence sought exists. Id. In spite of the power to require a blood alcohol test, the South Dakota Legislature has decided to grant its citizens the option to refuse to submit to such a test, unless they have been convicted twice in the last five years for driving while under the influence. See SDCL 32-23-10; State v. Hartman, 256 N.W.2d 131 (S.D.1977). Once an individual has been convicted twice for a violation of SDCL 32-23-1, a trooper is only required to inform an arrested person of the warnings outlined in SDCL 32-23-10, and the result of a compulsory blood alcohol test is admissible. See State v. Parker, 444 N.W.2d 42 (S.D.1989). Since Trooper Lanning followed the proper procedure, admission of the blood alcohol test result would be in accord with Schmerber and Hartman.
Heinrich contends that in spite of the correct procedure his blood alcohol test was improper due to the unconstitutionality of SDCL 32-23-10. According to Heinrich, the statute improperly delegates judicial powers to an executive officer in violation of the separation of powers doctrine. When the constitutionality of a statute is challenged, this court will uphold the statute unless its unconstitutionality is shown beyond a reasonable doubt. State v. Big Head, 363 N.W.2d 556 (S.D.1985). Heinrich has not shown SDCL 32-23-10 to be unconstitutional beyond a reasonable doubt.
A trooper’s initial determination that an individual is being arrested for a third violation of SDCL 32-23-1 is not an exercise of “unreviewable judicial power,” as stated by the trial court, but instead is a proper executive function. The trooper is merely making a preliminary determination as to whether an individual is entitled to the statutory grant of the right to refuse to submit to a blood alcohol test. This determination is simply a preliminary judgment necessary to enforce the statute. It is not a final and binding judicial determination. The trial court is not bound to accept the determination made by the trooper. If the court determines that either of the prior two convictions are invalid, then it may treat the result of the blood alcohol test the same way it would treat any improperly procured blood alcohol test result. No matter what determination the trooper makes about prior convictions, the trial judge ultimately decides what evidence will be admitted.
When executing and enforcing the law, it is necessary for a trooper to form judgments and interpret the law. Such conduct does not invade the power of the judicial branch because these decisions by the trooper are preliminary and are not binding upon the judiciary. In such a situation the trooper’s conduct cannot be considered the execution of judicial power. See City of Cedar Falls v. Flett, 330 N.W.2d 251 (Iowa 1983).
Heinrich also contends that SDCL 32-23-10 violates his equal protection rights under the United States and South Dakota Constitutions because the statute treats third-time offenders different than first or second-time offenders. We find this argument unpersuasive. If a statutory classification relates to a proper governmental purpose, it will be upheld. McGowan v. State of Maryland, 366 U.S. 420, 81 S.Ct. 1101, 6 L.Ed.2d 393 (1961). Limiting the statutory privilege to refuse to submit to a blood alcohol test is rationally related to the State’s proper interest in protecting its citizens from drunk drivers. Therefore, SDCL 32-23-10 does not violate equal protection rights. Nor, by the same reasoning, does it violate the due process clauses of the constitutions of the United States or the state of South Dakota. “If a regulation is reasonable in relation to its subject and adopted in the interests of the community, it does not violate substantive due process.” Woods v. Holy Cross Hospital, 591 F.2d 1164, 1176 (5th Cir.1979) (citing West Coast Hotel Co. v. Parrish, 300 U.S. 379, 57 S.Ct. 578, 81 L.Ed. 703 (1937)).
*28WUEST, C.J., and MORGAN and MILLER, JJ., concur. HENDERSON, J., dissents.. SDCL 32-23-1 provides, in part:
A person may not drive or be in actual physical control of any vehicle while:
(1) There is 0.10 percent or more by weight of alcohol in his blood as shown by chemical analysis of his breath, blood or other bodily substance;
(2) Under the influence of an alcoholic beverage[.]
. SDCL 32-23-10 provides, in part:
The person shall be requested by the officer to submit to the withdrawal of blood or other bodily substance for chemical analysis or chemical analysis of his breath and shall be advised by the officer that:
(1) If he refuses to submit to the withdrawal or chemical analysis, no withdrawal or chemical analysis may be required, unless he has been arrested for a third violation of § 32-23-1, constituting a felony offense under § 32 — 23—4[.]