Under Pennsylvania law, blood must be taken from a DUI defendant within two hours of his being in physical control of a motor vehicle. Specifically, under 75 Pa C.S. § 3801 § (c), in order for an accused to be found guilty of dui, the defendant's blood alcohol content must be measured as over .08% within two hours of his having driven on a roadway. read about implied consent here If the blood is drawn more than two hours after an accused was operating a vehicle, then it is per se inadmissible in a court of law. The Pennsylvania Superior Court made this holding in the case of the Commonwealth vs. Segiday (holding that the Commonwealth's evidence was insufficient to support either of Segida's convictions - under 3802 §§ (a)(1) or (c));
In cases such as these, the government frequently argues that the two-hour rule is not a per se rule of admissibility but goes to reliability, which may be argued at trial. The government frequently suggests that the controlling cases are Commonwealth v. Zugay, where the Superior Court said that the amount of time elapsed between driving and taking the sample does not affect admissibility, but rather only affected the weight of the evidence. .
The Government's argument is without merit: the two-hour rule is a per se rule; chemical test evidence of a dui defendant's blood or breath is inadmissible absent an exception based on a showing of good cause. Pennsylvania's DUI statute dates back to 1976, when the legislature enacted the earlier dui statute. In 1982, the legislature added subsection (a)(4) to prohibit driving while the blood alcohol content was .10% or greater. defending DUI cases But the statute contained no time limit on obtaining evidence of blood alcohol content. In 1992, the legislature enacted 3731 § (a)(5), implementing a three-hour time limit for BAC tests.). However, in 2004, Pennsylvania completely revised its DUI laws, explicitly implementing a two-hour requirement for many of the blood tests used to prove intoxication. Therefore there is a hard and fast two hour time limit for the government to take an accused's blood or breath.