Experts tell panel THC levels aren’t a reliable impairment measure; oral‑fluid testing and DRE evidence debated

Delaware officials told a legislative task force on impaired driving that existing science does not support a simple per‑se THC threshold and urged caution before adopting new testing laws.

Tom Donnan and Steven Smith from the Office of Defense Services and the Kent County Public Defender’s Office said THC is fat soluble and can remain detectable for days or weeks in some users, a characteristic that makes biofluid levels a poor proxy for impairment. Donnan cited national reviews and said: “THC levels in biofluids are not accurate or reliable indicators of impairment.”

Delaware State Police corporal William Scholl described the Drug Recognition Expert program, the 12‑step DRE evaluation and the program’s nationwide standardization, but also noted legal limits on admitting DRE testimony as full expert opinion in court.

Prosecutor Bart Lazrod and other presenters stressed the practical difference between finding evidence of impairment in the field and proving impairment in court. Law enforcement and attorneys said the state will benefit from the upcoming oral‑fluid summit, where technical vendors, prosecutors, law enforcement and treatment professionals will discuss the state of the science.

Panelists urged parallel efforts: public education about the risks of mixing substances with alcohol, better interagency data sharing and piloting oral‑fluid tests in controlled probation populations before expanding statutory testing rules. Probation Director Heidi said her office is piloting oral‑fluid testing and will share initial results with the committee.

The committee asked staff to invite the summit presenters and treatment providers (including Brandywine Counseling) to testify at a future meeting and to provide data on treatment costs and recidivism.

The hearing closed after a virtual public comment urging the panel to examine how treatment program costs affect people’s ability to complete court‑ordered services and avoid repeat offenses.