You did not give the section number for the statute you're asking about, but only the Title number which refers to the entire volume on Crimes.  But I tried doing a phrase search in title 17-A for "Obstructing public ways," and this is what came up.  I believe this is the section you were referring to? 

Title 17-A §505. Obstructing public ways

1.    A person is guilty of obstructing public ways if he unreasonably obstructs the free passage of foot or vehicular traffic on any public way, and refuses to cease or remove the obstruction upon a lawful order to do so given him by a law enforcement officer.

[ 1975, c. 499, §1 (NEW) .]

2.    As used in this section, "public way" means a way, including a sidewalk, owned and maintained by the State, a county or a municipality over which the general public has a right to pass by foot or by vehicle, a way upon which the public has access as invitees or licensees or a way under the control of park commissioners or a body having like powers.

[ 2017, c. 432, Pt. C, §2 (AMD) .]

3.    Obstructing public ways is a Class E crime.

[ 1975, c. 499, §1 (NEW) .]

SECTION HISTORY

1975, c. 499, §1 (NEW). 2015, c. 358, §2 (AMD). 2017, c. 432, Pt. C, §2 (AMD).

I'm not sure if this can be applied to road association roads.  They are not "owned and maintained" by the public; however, they might qualify as "a way upon which the public has access as invitees or licensees," and the road association might qualify as "a body having like powers."  But I'm not an attorney, so I'm not supposed to interpret law or give legal advice.  If you have an attorney you can ask without paying an arm and a leg, they might give you a better answer.  Meanwhile, I would suggest printing off a copy of the law and handing it to the officer when you make your complaint, or at least give him the title AND SECTION number so he can look it up.  Here is a link to the statute:

http://legislature.maine.gov/legis/statutes/17-A/title17-Asec505.html