I have read the whole thread, and here are some of my thoughts.
People respond differently to ingestion of impairing compounds, be it alcohol, marijuana, narcotics, medications and even non chemical causes like sleep deprivation.
Back when I used to have more drinks, I do not think a 0.05 would be an issue for me. Now that I hardly drink anymore, I think 0.05 would cause some impairment. Maybe once a month I get together with some guys after work and I limit myself to 1 beer. One night I had two beers and did not like driving home. Anymore, one drink is ok, but two seems to have an effect. If I would start drinking more, the liver enzyme induction would kick again and I would probably be good to go. Tolerance is well proven for alcohol, marijuana and narcotics.
Some people are impaired and should not be driving after no ingestion. But that is another topic.
I found the studies that Dakota Deer posted very interesting. They documented impairment at very low levels, but does that low level of impairment have a statistical impact on accidents resulting in property damage and deaths? Is that not what we are trying to prevent? If DUI drivers never caused property damage or deaths, would anyone care besides the do gooders?
What would be the actual decrease in property damage and saved lives in reducing the level to 0.05 from 0.08?
A number of people have mentioned a revenue stream as being the other reason. I think there is a huge behind the scenes push by the insurance companies for this lowering, Piggybacking on the emotional (MADD) argument and the Do gooder (control) portion of society.
For insurance companies it is ALL about the money and marking those people in actuary tables that could possibly cost them money and hurt their bottom line. If you get a DUI and do not cause any property damage or fatalities, your insurance rates will still go up. Why? you did not cost them any money.
DUI's are a very grey area of law with a lot of interpretation by the individual officer no matter how well trained they are. I am not comfortable with one LEO having that much power to ruin one's life. Because just like any other profession, you have very competent ones, and not so competent.
I am not comfortable with DUI checkpoints, no probable cause, just a fishing expedition. Why should a person be subject to search and interrogation when no probable cause has been witnessed? I am not comfortable for being automatically guilty if you refuse a test? They need to prove impairment. Society has gone overboard trying to prevent, with a subsequent loss of civil liberties.
For me it seems the answer is to never get behind the wheel if you have had anything to drink, but I just enjoy a beer with pizza, wine with pasta, and bourbon with steak too much when eating out. If my wife or kids are driving I may have two.
Society has had substance abuse issues since the beginning of time. I do not know the answer, but self responsibility is the best answer.
