Pennsylvania's Vehicle Code permits the punishment of driving if there is found in the motorist's blood measurable levels of inactive marijuana metabolites. The Department of Health has chosen not to publish "minimum detectable limits" for active Marijuana, but has listed the inactive Marijuana metabolites.

One can argue that the state has no power to punish the status of past marijuana user, and that punishment of operating some days after smoking Marijuana is an unconstitutional abuse of the police power. See, Memorandum on blood testing requirements & Constitutionality of DUI Marijuana Metabolite rules.

A primer on the toxicology of Marijuana and its metabolites is provided in Baselt, The Disposition of Toxic Drugs in Man.

The Superior Court of Pennsylvania had approved the metabolite rule in Commonwealth v. Etchison, 2007 PA Super 26,  916 A.2d 1169. However, the Pennsylvania Supreme Court has now agreed to review these questions (Appeal granted by, in part, Appeal denied by, in part: 2007 Pa. LEXIS 2343) (Pa. Oct. 26, 2007) (the Petition for Allowance of Appeal is GRANTED, LIMITED TO the issue set forth below: (1) Whether sub-section (d)(1) of the D.U.I. statute (75 Pa.C.S. § 3802) is unconstitutionally overbroad and thus violative of the right to due process?), Stay tuned!