Timing Is Everything: When Does PA’s 10-Year Look-Back Period for Enhanced DUI Penalties Begin to Run?

Pennsylvania’s Vehicle Code mandates enhanced sentencing penalties for repeat DUI offenses committed within 10 years of a “prior offense.” But when does the clock begin to run? In a case of unfortunate timing for one DUI defendant, the Pennsylvania Supreme Court recently provided an answer.

Two DUI Offenses

In Commonwealth v. Mock, a driver committed a DUI offense on June 3, 2006, which resulted in a conviction on March 27, 2007. More than 10 years after committing this offense, but roughly nine years following his conviction, the driver committed another DUI offense.

On July 10, 2016, police stopped the driver after observing him cross the fog and center lines several times while driving on the highway. He was arrested on suspicion of DUI and transported to the hospital where he consented to a blood test. The test revealed a blood-alcohol-content of 0.21 percent. He was later charged with DUI ― highest rate of alcohol. The Commonwealth deemed his DUI a second offense and graded it as a misdemeanor of the third degree subject to increased penalties.

The defendant argued that the Commonwealth improperly characterized his DUI as a second offense because the first driving offense (as opposed to the conviction) occurred outside the 10-year period. The trial court rejected the driver’s argument, explaining that the previous conviction took place less than 10 years prior to commission of the second offense. The driver proceeded to trial and was convicted of DUI ― highest rate of alcohol as a second offense. He was sentenced to 90 days to five years of imprisonment. It was an enhanced penalty which took into account his first DUI offense.

The driver appealed to the Superior Court of Pennsylvania, where he continued to argue that the Commonwealth improperly characterized the instant DUI as a second offense, subjecting him to increased penalties. The Superior Court rejected the argument, and the driver appealed to the Pennsylvania Supreme Court.

Pennsylvania Supreme Court Decision

The Pennsylvania Supreme Court looked to the plain language of the vehicle code in determining that the look-back period began to run on the date of the driver’s first DUI conviction, as opposed to the date when he drove under the influence:

In sum, the plain language of Section 3806 mandates that the ten-year lookback period for DUI offenses, relevant for grading and penalty purposes, runs from the occurrence date of the present offense to the conviction date of the earlier offense. Appellant’s previous conviction occurred less than ten years prior to the commission of the present offense. He was therefore properly convicted of DUI — highest rate of alcohol, as a second offense. Accordingly, we affirm the order of the Superior Court affirming Appellant’s judgment of sentence.


Although the outcome was not favorable for this particular defendant, the case underscores how statutory interpretation can be a crucial component in defending against DUI charges. As always, if you are arrested for DUI, it is imperative to retain a knowledgeable DUI defense attorney to ensure that your legal rights are protected and that you can mount a vigorous defense.