The appellant, Susan Womack, was convicted in the Fifth Circuit Court of driving under the influence of alcohol, and her conviction was sustained by the district court. We affirm the district court.
On January 8, 1982, Womack was stopped by a Salt Lake City police officer for a routine traffic violation. When she rolled down the window of her car to speak with the officer, he detected an odor of alcohol. He asked Womack if she had been drinking, and when she responded that she had, he requested that she take a series of field sobriety tests. Based on Womack’s performance on the tests, the officer arrested her for driving under the influence of alcohol.
Womack was transported to the Salt Lake County jail, where another officer explained the terms of the Utah Implied Consent Law and administered a breathalyzer test approximately one hour after she had been stopped. The test showed a blood alcohol content of .16%. No Miranda warnings were given to Womack.
On appeal, Womack challenges the admission of the breath test result on the ground that it did not have an adequate evidentiary foundation. She asserts that due process was violated by the short delay in the administration of the breathalyzer test. Womack also claims that Utah’s Im *1041 plied Consent Law, Utah Code Ann. § 41-6-44.10 (Supp.1987), violates due process and equal protection under the United States Constitution and the right against self-incrimination under Article I, section 12 of the Utah Constitution. Further, she asserts that the field sobriety test violates her right against self-incrimination under the Utah Constitution. She also claims error in the admission of her inculpatory statement made to the officer before a Miranda warning was given to her. Finally, she challenges a jury instruction which, she claims, required the jury to presume guilt.
I.
When this appeal was filed, this Court had jurisdiction to entertain appeals from cases commenced in the circuit courts only with respect to constitutional issues. Utah Code Ann. § 78-3-5 (1981);
Layton City v. Watson,
II.
Womack also contends that “for constitutional due process to be afforded ... there must be some evidence of the amount of alcohol in her blood at the time of driving to determine if the appellant was [driving] under the influence of alcohol....” She argues that since the breathalyzer test was administered about an hour after she was stopped on the street, the breathalyzer test of her blood alcohol content did not accurately reflect her blood alcohol content at the time she was stopped.
The officer who initially stopped Womack and administered the field tests and the officer who subsequently gave the breath test observed Womack virtually constantly from the time of the stop until the time of the breath test. No testimony was elicited from the officers on either direct or cross-examination which indicated that Womack had anything in her mouth during this time period. Furthermore, the officer who administered the breathalyzer test specifically testified that he observed Wom-ack for a period of approximately forty-five minutes prior to the test and that during that time he did not observe anything in her mouth. This observation period is clearly adequate to render the breathalyzer result reliable.
See State v. Baker,
III.
The appellant also claims that the Utah Implied Consent Statute is unconstitutional on equal protection and due process grounds. The statute denies equal protection, she argues, because it requires that an officer, rather than a suspected intoxicated driver, choose whether the test to be administered is a breath, blood, or urine test. See Utah Code Ann. § 41-6-44.10 (1981). The appellant’s point is that suspects, and not the police, should be allowed to choose which test will be administered because of differences in accuracy between the tests. The appellant *1042 has not shown, however, that significant differences exist between the different tests with regard to accuracy. . Since the appellant’s argument has no factual foundation in this record, it is without merit.
The appellant also argues that due process was denied her because multiple breath tests were not conducted to verify the result of the first test. That contention was addressed and rejected in
Layton City,
IV.
Womack next challenges the admission of the field sobriety test results as a violation of her right against self-incrimination under Article I, Section 12 of the Utah Constitution, which states in part: “The accused shall not be compelled to give evidence against himself_” Womack contends that she was compelled to take the roadside field sobriety tests and thus was forced to give evidence against herself. She asserts that at the time of her arrest and trial, this question was governed by our decision in
Hansen v. Owens,
In
Hansen,
this Court held that a defendant could not be compelled to provide a handwriting exemplar because that would be a violation of Article I, Section 12. If
Hansen
were in fact controlling, Womack might prevail. However,
Hansen v. Owens
was specifically overruled in
American Fork City v. Crosgrove,
Womack also argues that
Cros-grove
cannot be applied in this case because of the state and federal constitutional prohibitions against ex post facto laws. Those provisions are not applicable. The constitutional ban on ex post facto laws applies only to legislative enactments.
Frank v. Mangum,
The appellant also challenges the admission of an inculpatory statement made to the arresting officer because
Miranda
warnings were not read to her before she made the statement.
Miranda
warnings must be given to motorists stopped on suspicion of driving under the influence of alcohol when the detention of a motorist moves from being an ordinary traffic stop to being an “in custody” detention for
Miranda
purposes.
Berkemer v. McCarty,
*1043 [[Image here]]
Finally, the appellant contends that the trial court erred in giving a jury instruction which she says required the jury to presume guilt conclusively because of the percentage of blood alcohol found by the breath test. The appellant did not object to the jury instruction at trial and, therefore, waived the right to challenge it here. Utah R. Crim.P. 19(c) (1982).
Affirmed.
Notes
. Under the current statutory scheme, this appeal would have been taken from the circuit court to the Court of Appeals and would not have been limited to constitutional issues. The district court would be bypassed. See Utah Code Ann. §§ 78-2a-3, 78-3-4 (1987).
. In fact, in almost every instance, a breath test administered sometime after the traffic stop will be advantageous to the DUI suspect in two ways. First, a foreign substance present in the mouth which might produce an artificially high result will be removed by absorption during the observation period. Second, in the interval between the traffic stop and the breath test, some of the blood alcohol usually will have been metabolized, resulting in a slightly lower test result.
. The appellant also asserts that
Elliott v. Dorius,
