Lost in the debate about lowering the legal limit for DUI to .05 is one simple fact. You can ALREADY be charged with DUI under Pennsylvania law, even if your BAC is below .08. The Pennsylvania DUI law does not only criminalize driving after imbibing enough alcohol to raise one's BAC above .08 within two hours of driving, it also makes it illegal to drive drunk period.
An NFL lineman can bench press 200 pounds for far more reps than I can, even though we are both adult men lifting the same amount of weight. Likewise, two people with the same BAC level may experience vastly differing degrees of impairment. For example, some people can drive safely at a .15 BAC. This is an objective fact, even if militant anti-alcohol crusaders call me irresponsible for making such an observation. On the other hand, some people are as drunk as Tucker Max at 4:00 a.m. after just a few beers. This is also an objective fact, but no one will throw a fit when I point this out.
Some people are too drunk to drive even at a mere .04 or .05 BAC. You have probably experienced some of these people at bars or parties. They tend to only drink a few times a year, on special occasions like New Years Eve, the Fourth of July or their own birthday. Through a combination of lack of practice and genetics, it does not take much to get these people drunk, even when taking into account weight and gender. We even have a handy term for such people. They are called "light-weights."
If a light-weight gets behind the wheel of a car even after just two or three drinks, there is a good chance he will make driving errors, which will be noticed by a cop skilled at DUI detection. The cop has no way of knowing how much a driver had to drink. All he or she notices is the bad driving. If you are swerving over the yellow and white lines, you are going to get pulled over whether your BAC is .06 or .26. Thereafter, if you are impaired, you will fail the standard field sobriety test, even if you are below the legal limit. The bad driving, coupled with failed field sobriety tests, will lead to a DUI charge.
It is rare for people to get DUIs below the legal limit. I believe the primary reason for this is because light-weights rarely drink, let alone drive drunk, thus reducing their opportunity of being caught. These people tend to only drink a few times a year, and when they do drink it is an "event," for which they plan accordingly. They will make arrangements for a designate driver or a taxi. Nevertheless, anyone who has practiced criminal defense long enough has at, some point, represented a defendant charged with DUI who was below the legal limit. The good news for these people is that they will not lose their driver's license if it is a first offense, either with or without admission into the ARD program.
Matt McClenahen is a criminal defense attorney in State College, PA with extensive experience in DUI defense. http://www.mattmlaw.com/Criminal-Defense-Overview/DUI-Defense.shtml