How are DUIs Investigated?
They sometimes have road stops which are administrative in nature and really you have to abide by them.
That's one of the methods the other way is in motor vehicle accidents. What's interesting is that the vast majority of motor vehicle accidents take place in the absence of alcohol. So I found that often to be a less likely scenario. Although it can happen, all the officer really needs is a legal reason to be there. Even if it's a speeding ticket. If they observe the indication of impairment at that point in time they have a reasonable suspicion to detain you long enough to establish whether or not they have probable cause to arrest you for a DUI or not.