What is the importance of Jurisdiction in Maryland DUI Law?
Know what Jurisdiction you were stopped in...This is the easy part, you simply have to know which county you are in, Baltimore County, Howard County, Anne Arundel County, etc. This is important because county police officers cannot simply stop you wherever they want. They must be within the limits of their jurisdictional authority. If they are outside those limits, then they become regular citizens like you and I.
Know what jurisdiction the officer is authorized in...This is also generally easy to know because if they are driving home, they may be driving their police vehicle which may be marked "Howard County Police." If you were stopped in Baltimore County then this raises a red flag as to what they are doing. They may even indicate in their statement of facts that they were driving home from work or driving to work etc., when they witnessed a your driving transgression. At that point they are supposed to merely follow the driver and call it in to local law enforcement who are in fact authorized to effectuate a stop. Sometimes, officers become over zealous and flip on their lights to make the stop prior to their back up arriving, this will not suffice in court.
Illegal StopThe reason that the stop will not stand up in court is because when the police are outside their jurisdiction, s/he becomes just like you and I. He has no additional power to effectuate a stop in this type of situation, although he is authorized to effectuate a citizen's arrest, just like we are. The difference in this case is that if he utilizes his police lights to make the arrest he is using police powers which he does not have at that time. This results in an illegal stop and arrest and any evidence that subsequently flows from that arrest, like a high BAC, becomes "fruit of the poisonous tree" or otherwise inadmissible. Remember however that the Maryland State Police are not subject to such limitations as they have jurisdiction throughout the entire state.