No random sobriety tests are not helping to stop or deter people from driving drunk. It might be helping to catch more drivers drunk driver, but people will most likely to continue to assume that it will not affect them or they will not be the ones to get busted by the cops.
There is no reason to randomly pull someone over and detain them, and random sobriety checks do just this. They are on predictable roads so they are avoidable if someone who has been drinking puts any thought into it at all, and they invade the lives and privacy of citizens that are legitimately traveling. Rather than randomly stopping and bothering everyone, police should be looking out for dangerous drivers and then stopping only those individuals.