dissenting.
I dissent from the majority’s conclusion that the trial court properly admitted Officer Weiss’ testimony that in his opinion appellant was under the influence of a controlled substance to a degree which impaired his ability to drive safely. I also dissent from the majority’s determination that the evidence *362was sufficient to support appellant’s conviction of driving under the influence of a controlled substance.1
In deciding that Officer Weiss’ testimony was admissible, the majority disregarded the results of the urinalysis revealing the presence not just of marijuana but also of Alprazolam, Hydrocodone and Benzodiazepine in appellant’s urine.2 Given that Officer Weiss clearly testified that he had no knowledge whatsoever as to the nature of these additional chemicals or their possible effects upon appellant’s ability to drive safely, N.T. at 45-47, Officer Weiss was not in a position to give an opinion that the source of appellant’s impairment was a controlled substance.3
In State v. Rifkin, 140 Vt. 472, 438 A.2d 1122 (1981), the Vermont Supreme Court reversed a conviction for driving; under the influence of a controlled substance because the non-expert arresting officer was improperly permitted to testify that in his opinion defendant was under the influence of a controlled substance, and to a degree which impaired his ability to drive safely. The Court explained that since chemicals, unlike alcohol, can cause''a wide array of symptoms unknown to laypersons, only an expert could testify as to whether a defendant is under the influence of controlled substances and impaired thereby to the extent that he or she is unable to drive safely. Id., 438 A.2d at 1124-1125.
I agree with the Vermont Supreme Court and would require expert testimony at least in those cases, such as the case at bar, involving chemicals in the defendant’s system other than *363controlled substances.4 In such cases, after a proper foundation has been laid, a lay witness may testify as to his or her observations. However, a qualified expert is required to provide the connection between the symptoms observed and the drug allegedly influencing the defendant’s driving. See Rifkin, supra, 438 A.2d at 1125.
Because I would find that the officer’s opinion that appellant’s impairment was due to a controlled substance should not have been admitted, I conclude that the evidence presented at trial was insufficient to sustain the appellant’s conviction. The statute, 75 Pa.C.S. § 3731, does not criminalize driving in an impaired state and does not criminalize the use of controlled substances. Rather, 75 Pa.C.S. § 3731 explicitly requires a finding that the defendant’s ability to drive be impaired by a controlled substance. The causation element of this statute which is explicit and necessary has not been proven in the instant case.
In my view, the Commonwealth failed to offer admissible testimony from which the fact finder could conclude beyond a reasonable doubt that appellant’s driving was impaired by the use of marijuana, as opposed to one of the other drugs that were in his system.5 Thus, I would reverse the judgment of sentence for driving under the influence of a controlled substance.
. I agree with the majority's conclusion that the appellant’s car was lawfully searched pursuant to appellant’s consent and that, therefore, the fruits of the search need not be suppressed.
. The Commonwealth’s expert testified that Alprazolam and Benzodiazepine are tranquilizers and Hydrocodone is an opiate pain killer or "narcotic analgesic.” He also testified that each of these are available only by prescription.
. The majority states that Officer Weiss testified that in his opinion appellant was under the influence of marijuana; however, my review of the record indicates that in fact Officer Weiss testified that he had no idea which controlled substance was influencing appellant, just that appellant appeared to be under the influence of some controlled substance. N.T. at 39-40.
. The signs of a person driving under the influence of alcohol are readily known to law enforcement personnel. They are the same whether the individual has ingested beer, wine or hard liquor. They derive from the alcohol content in the individual’s body. Drugs, on the other hand, contain different chemicals, and the reaction to each of the chemicals varies markedly depending on the combination and quantity of chemicals ingested, and the individual’s sensitivity to them. Thus, law enforcement personnel are not so readily able to detect the signs of a person driving under the influence of a controlled substance, and distinguish those signs from the effects of a drug which is not a controlled substance. Therefore, I find the majority’s reliance on case law relating to driving under the influence of alcohol to be misplaced.
. The Commonwealth’s urinalysis expert testified that no tests were conducted to determine the quantity of marijuana in appellant’s body, despite the availability of such tests. He further testified that the presence of marijuana could be detected in a marijuana user for up to thirty days after use.