JOHNSON, Presiding Judge.

Shawn Williams was charged with vehicular homicide, reckless driving, driving while under the influence of a drug, following too closely, and serious injury by vehicle. He moved to suppress results of a blood test that police obtained from him without first informing him of his implied consent rights. The trial court denied his motion, but certified the order for immediate review. We granted Williams' application for interlocutory review. For the reasons that follow, we reverse.

In reviewing a trial court's denial of a motion to suppress, this Court defers to the trial court's findings of disputed facts but reviews de novo the court's application of the law to the undisputed facts. The facts in this case are not in dispute.

In May 2006, Williams was involved in a fatal car accident. One of the investigating officers suspected that Williams might be under the influence of drugs. The officer asked Williams for a blood sample, but did not advise him of his implied consent rights. Williams agreed to give the sample, which showed the presence of marijuana in his system.

Williams moved to suppress the test results based on our recent decision in State v. Morgan, which held that in all cases in which police request a chemical test of a person's blood for the purpose of determining whether the driver was under the influence of alcohol or drugs, they must give the notice required by the implied consent statute. In Morgan, we noted that the implied consent statute affords a suspect the opportunity to refuse testing, and stated that we will not permit or encourage police to circumvent the mandatory implied consent statute by simply asking individuals, without reading the notice, if they will consent to testing.

The state responded to the motion by pointing to an amendment to the implied consent statute, OCGA § 40-5-67.1 (d.1), which provides that nothing in the implied consent statute

shall be deemed to preclude the acquisition or admission of evidence of a violation of [the DUI laws] if obtained by voluntary consent or a search warrant as authorized by the Constitution or laws of this state or the United States.

The state argued that the amendment, which took effect in July 2006, should be applied retroactively. We disagree.

A statutory amendment may be applied retroactively "if the changes do not affect constitutional or substantive rights and if the legislature did not express a contrary intention." Substantive law is that law which creates rights, duties, and obligations. Where a statute governs only court procedure, including the rules of evidence, it is to be given retroactive effect absent an expressed contrary intention. Procedural law is that law which prescribes the methods of enforcement of rights, duties, and obligations.

Georgia's Supreme Court has construed the implied consent law as granting a substantive right of refusal:

In Georgia, the state may constitutionally take a blood sample from a defendant without his consent. Strong v. State, 231 Ga. 514 ( 202 SE2d 428) (1973). Our "Implied Consent Statute" (OCGA § 40-5-55) thus grants a suspect an opportunity, not afforded him by our constitution, to refuse to take a blood-alcohol test. OCGA § 40-5-55 creates the right to refuse. OCGA § 40-6-392 defines the right.

"[These statutes] grant, rather than deny, a right to a defendant." Moreover, "[t]he right of refusal is reinforced by the express language of OCGA § 40-5-67.1 (d)."

The state argues that the amendment at issue here simply expands the scope of evidence admissible at trial, and so constitutes a procedural change. To support its position, the state cites cases holding that a different amendment to the implied consent statute was merely procedural and therefore applied retroactively. The amendment in those cases, however, affected only the nonsubstantive specific content of the implied consent warnings and whether the warnings had to be given verbatim. The amendment changed neither the substance of the warnings themselves nor the substance of a defendant's rights as stated in the warnings.

The amendment at issue here, however, is different. It states that nothing in the implied consent law precludes the state from acquiring a defendant's voluntary consent to chemical testing, or admitting into evidence the results of that testing. The implied consent statute grants drivers the right to refuse to take a state-administered test, with one of the consequences of exercising that right being that evidence of such refusal is admissible at trial. Unlike the amendment at issue in the cases relied upon by the state, the amendment here eliminates the need to give the notice where an individual "voluntarily" agrees to testing. This amendment not only changes the substance of the implied consent warning, it does away with the requirement that the warning be given at all where an officer manages to otherwise lawfully obtain consent to testing. This is not merely a procedural or evidentiary change, but one eliminating a defendant's substantive right to refuse to submit to testing. Therefore, the trial court erred in applying the amendment retroactively and in denying Williams' motion to suppress.

Judgment reversed. Ellington and Mikell, JJ., concur.

JOHNSON, Presiding Judge.

DECIDED APRIL 23, 2009.