I am unaware of your source, but recent studies have shown that drivers show signs of serious impairment at levels far below .08. The .08 level is really quite arbitrary and to my knowledge was not based on any actual study of impairment. You might be comfortable with .08, but the person you run into at that level might have a different opinion.
Impaired Driving - Why You Should Never Drink and Drive
I note that in Alberta the strongest opposition to lowering the level below .08 did not come from any scientific body, but the restaurant and bar industry. To hell with the fact that drinking a driving kills and injures thousands of people a year so long as restaurants and bars can maintain their sales levels. Capitalism at its best.
Restaurants fear losses if drunk driving laws toughened - Calgary - CBC News
Same group in BC opposed it - The Libs almost pulled the law due to pressure from these groups