While I generally support strict regulations prohibiting drinking and driving, I think no alcohol at all isn't practical. Alcohol is also used to prepare some meals. Most of it will be evaporated when cooking, but quite a few deserts also have alcohol in them.
Where I live the limit is 0.05% BAC. When you fail a breathalizer test (just shows safe or positive), you have to take a blood test to determine the amount of alcohol in your blood. The blood test can show up negative (in which case you're allowed to continue, no harm done), or confirm that you're actually above the limit. There's a different punishment for being in the 0.05% - 0.08% range, or higher.
* 0.05 - 0.08%: you're not allowed to drive for 3 hours, and you are fined
* > 0.08%: you're not allowed to drive for at least 6 hours, your license can be revoked (not the policeman's decision) for at least 15 days, and you can also serve some time in jail if it's serious enough.
If I'm not mistaken you can also ask to delay the breathalizer test for 15 minutes to get rid of any traces of alcohol in your mouth (mouth wash/you just drank something/...).
As far as I'm concerned, an ignition interlock would be perfectly acceptable for the 0.08%+ category, especially for repeat offenders or first offenders considerably over the 0.08% high limit.
If you're in an accident and you seriously hurt/killed someone, you'll very likely think 'what if...' no matter what you did. What if I had looked in that direction at that time, what if I hadn't filled up the tank first, what if I would have been driving a little slower, ...