The time of day also plays a big part in whether the cops pull you over or not. if it is 2:30 in the morning and there is not many cars on the road, the police know what time the bars close, and closely watch cars coming from bar districts and much more likely to pull them over, however if you leave the bar by 10:30-11pm, even if you are slightly buzzed, you probably will be OK.
The thing about the home breathalyzers is it does not factor in when a person has eaten, eating and letting it digest seriously kills a persons drunkenness, but the device may still read they are over the limit.
Personally, I believe the powers that be would try something new if they were truly interested in stopping DUIs, if you look at years past, you will see DUIs are increasing in numbers, despite the laws against them, so this shows the current laws are not working. You can not expect new results when trying the same old thing time after time, everyone knows this. I tend to think cities and counties rely a bit too heavily on fines coming in from DUI cases, and if they were truly devoted to stopping drinking and driving, they would be coming up with something new to combat it, and not just another punishment, they would employee modern science and experts in this field to come up with alternatives, I for one, believe they could come up with a pill or syrup, that when taken, will kill a persons buzz within 15-20 minutes, allowing them to drive home. There is a chemical that has been shown to do this, but I cannot recall the name.
On the other hand, if the self driving car comes to fruition like many say it will, DUIs will be a thing of the past anyway, I believe CA has these on the road now and probably within the next 10 or so years, the rest of the country will get them.