Thank you for providing this useful information.  However, unfortunately I don't believe it's much help in this case.  First of all, the "class E crime" listed in the section you provide has little to do with parking on a private road.  Rather, it refers to when you are driving on a road and meet an emergency vehicle with its lights on.  If you do not then yield the right of way so that vehicle can pass, that is a class E crime.  So this section MIGHT apply if an emergency vehicle had to use the private road and the resident had parked their vehicle in such a way that the emergency vehicle could not get through, but this class E crime would not apply unless or until an emergency vehicle was actually prevented from responding to an emergency.  If the resident saw or heard the emergency vehicle coming and immediately moved his car, there would be no crime.

A closer match would be http://legislature.maine.gov/legis/statutes/17-A/title17-Asec505.html which makes it a class E crime to obstruct a public way.  I had thought this statute would not apply to private roads.  However, your post motivated me to look up the statute once again, and I find that it was amended in 2017, and now defines "public way" to include not only roads that are maintained by the public, but also roads "upon which the public has access as invitees or licensees ."  I believe that amendment now makes Title 17-A section 505 apply to private roads.  So, thank you for leading me to make this discovery!

Now, as to the E911 manual, the link you provided has within it a link to the addressing officer's manual.  So I followed that link and then looked up the section on "Maintaining the Emergency Road Network."  As far as I can see, this section merely requires the addressing officer to maintain an accurate list of roads and addresses within his area.  It has nothing to do with maintenance of the roads,or even assuring that the roads remain unobstructed.  I then did word searches within the document for various terms that might lead me to any other passage that would apply, but found nothing.  

On the other hand, the link you provided is still helpful in that it also provides a link where you can find out who your local addressing officer is.  That should also allow anyone to check and see that their road and address are correctly indicated on E911 maps.  It's a good idea to check.  In my own case, we live on a former county road that remains a "public easement," that is, it is open to the public but receives no public maintenance.  Our 911 addressing committee was not careful in their designation of the road, with the result that the addresses were numbered from the out-of-town end in, (contrary to E911 rules,) and the entire road was listed under one name even though the middle half mile is impassable most of the year.  As a result, we have had emergency vehicles come in our end on four different occasions when they needed to be responding to the other end of the road.  Last year they finally gave the other end of the road a new name.  However, the new name still does not come up in a Google Earth search or GPS, and we have been told that most volunteer responders rely on GPS, not on the E911 data base.  To make matters worse, Google Earth and GPS somehow got our address moved to a mile away from our house, on a road that connects to the wrong end of our county road.  So it's definitely worth following the link you provided and checking to see that your address is correctly located for E911 purposes.