PA Court Upholds DUI Drug Conviction Despite Improper Testimony
Posted in DUI on July 3, 2025
The Pennsylvania Superior Court recently issued a published opinion in Commonwealth v. Greene, reaffirming that police officers’ improper “expert” opinions at trial may be harmless error when other evidence overwhelmingly supports a conviction. The case offers important lessons for both defense attorneys and drivers facing DUI drug charges in Pennsylvania.
The Facts: Traffic Stop Leads to PCP DUI Charges
Greene was pulled over by Williamsport Police after allegedly speeding and nearly causing a rear-end collision. During the traffic stop, officers noted signs of impairment, including:
Slurred speech and confusion
Difficulty following instructions
Poor performance on field sobriety tests
The odor of PCP coming from Greene and his vehicle
A cigarette containing PCP found in Greene’s car
Greene waived his right to a jury trial and proceeded with a bench trial in Lycoming County. He was convicted of DUI controlled substance (PCP), possession of PCP, and possession of drug paraphernalia. The court sentenced him to state incarceration and probation.
The Appeal: Was the Officer’s Testimony Improper?
On appeal, Greene argued that:
The officer improperly gave expert testimony that Greene was under the influence of PCP, despite not being qualified as an expert.
The evidence was insufficient to prove impairment without expert testimony.
The Commonwealth’s reliance on alleged speeding was flawed, as Greene was acquitted of the speeding charge.
The Superior Court agreed that the officer’s testimony crossed the line from permissible lay observations into improper expert opinion. Specifically, connecting Greene’s behavior to PCP impairment required specialized knowledge beyond that of an average person.
Cop Was Not an Expert
The Superior Court wrote that the officer could testify as to what he observed, meaning he could testify that Greene had slurred speech and confusion; difficulty following instructions; poor performance on field sobriety tests; and the odor of PCP coming from Greene and his vehicle. The testimony that was improper was the officer’s testimony that those things were evidence that Greene was impaired due to PCP. Such testimony was expert opinion testimony, and that requires the prosecutor to request that a witness be qualified or accepted as an expert. The trial judge should not have allowed such opinion testimony that directly linked the behaviors to PCP use without being qualified as an expert.
Harmless Error: Why the Conviction Stood
Despite finding the officer’s testimony improper, the Court upheld the conviction, concluding the error was “harmless”. The Commonwealth presented overwhelming, independent evidence of Greene’s impairment, including:
Observable driving behavior (nearly causing a collision)
Multiple failed field sobriety tests
Discovery of a PCP-laced cigarette
Another officer’s testimony about the smell of PCP
Because the remaining evidence was strong enough to support the DUI conviction, the improper testimony did not affect the outcome of the case. Therefore, the Court affirmed the conviction by ruling that the admission of the expert testimony was “harmless error.”
Key Takeaways for Pennsylvania Drivers
DUI Drug Charges Do Not Always Require Expert Testimony: While officers cannot testify as experts unless properly qualified, courts may uphold DUI convictions based on observable evidence and credible officer observations.
Behavior and Performance Matter: Field sobriety test performance, demeanor, speech, and other factors can establish impairment, even without scientific blood test results.
Acquittals on Traffic Violations Don’t Erase DUI Evidence: Even if a person is found not guilty of speeding or other minor infractions, evidence gathered during the stop may still support a DUI conviction.
Facing DUI Drug Charges in State College? Know Your Rights.
This case highlights the complexities of DUI drug prosecutions in Pennsylvania. Improper testimony, field sobriety tests, and other forms of evidence require careful legal analysis. If you’re charged with DUI involving drugs, particularly when no blood test is involved, it’s crucial to have an experienced defense attorney review every aspect of your case.
At JD Law, P.C., we focus exclusively on criminal defense and have extensive experience handling DUI cases. For a free case review, contact JD Law by email or leave a message at (814) 689-9139. Email is the preferred method of communication, as phone calls are directed to voicemail due to the high volume of spam and unsolicited calls.