The question was how many DUI's does it take to revoke a license in Maryland? Well.... an extended answer would be....
When you get a DUI/DWI in Maryland assuming that the paperwork was completed properly DR-15 (advice of rights), DR-15A (order of suspension), etc... it gets mailed off to the MVA.
At some point, if you were given a temporary drivers license, you have the right to request an administrative hearing (and you have to mail away with a filing fee). To get your "license" back while awaiting your court date, you will have a hearing at the MVA in front of an administrative judge. They will decide whether it stays suspended, if you get an interlock, etc. PBT evidence can be presented against you here (unlike criminal court where it cannot be used against you unless your defense attorney drags it out of the officer). A re-examination of the driver could include a vision/hearing test, retest of the driving laws or driving the course again depending on what went on. After a certain number of DUI's the manager of an MVA could ask for a re-examination of the driver if they wanted to, or even a family member could petition the MVA for the re-examination of a driver if they wanted to.
When you get to criminal court, depending on what the individual pleas to, may determine what happens with the license. PBJ's usually go away however if the individual gets another DUI/DWI etc, the previous offense can be brought back up into court. Lets say someone is on their 3rd DUI and keeps getting PBJ, paying their fines etc. If the judge doesn't impose the points on the individuals driving record, the license may not get suspended. There are many factors that go into this, but it usually takes something bad to happen before people like this are exposed. Someone who is on their 5th DUI and kills someone... its 1 news article away from exposing revolving door judges.
Other things to take into account are the jurisdiction where the DUI is charged. Where places like Calvert and Worcester Co might take it serious and order drug/alcohol counseling, interlock for a year, supervised probation, MADD meetings, jail time on the weekends, ordered to abstain from alcohol/drugs, etc, its jurisdictions like DC, PG, MoCo where you have to hope and pray the case was high profile because outside of that they simply don't have the room nor do they care to prosecute traffic offenses. Their numbers show too, as the majority of alcohol related crashes and fatalities tend to rack up easily in these areas, with no relief coming anytime soon. Cops there are often bogged down with violent crime and massive amounts of calls for service too. Lawyers factor in too, for the right price, a good lawyer can mitigate even the worse DUI case against an individual.
Lastly, don't expect DUI laws to get tougher in Maryland anytime soon. Mike Miller (your elected leader) is an excellent DUI lawyer in the off season and so are many other representatives in the state legislature. Now why would they make their jobs as defense attorneys harder you have to ask yourself? And like the one guy said, even if you are found guilty and your license gets suspended or revoked, you can always move to DC and get a new one, you just can't drive in Maryland. DC MVA will give you a license for the right price. Supposidly Maryland MVA in Largo will too, I read an article on the feds investigating people purchasing CDL licenses and MVA employee's giving people drivers licenses for the right prices.
Too many words!!!