Disclaimer - I am not an  attorney, and cannot interpret law or give legal advice.  The following is just my personal opinion, based on my own experience.  Take it or leave it for what it's worth.

It's too bad you don't have bylaws that address this sort of thing.  In looking at 23 MRSA 3101, paragraph 5, I see that it says,

"The determination of each owner's share of the total cost must be fair and equitable and based upon a formula provided for in the road association's bylaws or adopted by the owners at a meeting called and conducted pursuant to this section. "   

At our 2020 annual conference, attorneys Mary Denison and John Cunningham stressed the importance of following the law to the letter, and particularly the importance of having a formula for determining each owner's share of the cost.  The "fair and equitable" clause seems to have been taken by the Courts as meaning that whatever formula you have agreed to must be applied equitably to everyone.  So if you have agreed that each member pays the same amount, that is your formula.  However, it appears from the passage above that if you don't have bylaws with a formula, then your other option is to adopt a formula at a meeting called and conducted as specified in section 3101.  So as long as you follow the procedure for calling a meeting, you should be able to decide on a formula at that meeting.  

So, what would be "fair and equitable" if one member has caused damage to the road?  It seems to me that it wouldn't really be fair to let one person damage the road and force everyone else to share the cost of repairing it.  Our bylaws include the following paragraph:

"Any damage to the road by an owner, his/her guests, or his/her contractors beyond normal wear and tear shall be the responsibility of that owner, and the cost of any repairs necessitated by such damage may be assessed against said owner by the Board of Directors."

I consider that to be part of our "formula" for "determining each owner's share of the total cost" as specified by section 3101.  I would recommend that if you are going to propose such a formula, you should include that in your meeting notice 30 days before your meeting. 

My one concern is that since you do not already have that in your formula, you might get some backlash for applying a new policy to damage that was incurred before you had that policy.  You could try approaching the person who did the damage and appealing to his sense of fairness, explaining that it would not be fair to make everyone pay for damage that was solely his. 

If push comes to shove, lawsuits can get frightfully expensive, and likely it would be cheaper for both parties to just suffer the cost of the repair.   If any of the land qualifies as agricultural land (including land in forest production,) it might qualify for dispute resolution through the Cooperative Extension's Agricultural Mediation Program, which is offered free or at nominal cost if both parties agree to participate.

As to the problem of one person plowing the road while the rest want it left in a condition that can be used by snowmobiles, you are the second person I've heard from with this complaint.  (Is it the same road, or is there more than one road that's having this problem?  You can send me an email at roadways@juno.com.)  Is there by any chance any clause in the deeds or in any subdivision plan indicating that access is to be seasonal, or that the roads are intended for use by snowmobiles?  This might be a case of "overburdening," where a person subjects a right of way to more than it was intended for, or more than it has traditionally been used for.  And if the road itself is part of the ITS trail system, it may actually be illegal to plow it or to operate a motor vehicle on it during snowmobile season.  See Title 12, §13107. Unlawfully operating vehicle on snowmobile trail:

"A person may not operate any 4-wheel-drive vehicle, dune buggy, all-terrain vehicle, motorcycle or any other motor vehicle, other than a snowmobile and appurtenant equipment, on snowmobile trails that are financed in whole or in part with funds from the Snowmobile Trail Fund, unless that use has been authorized by the landowner or the landowner's agent, or unless the use is necessitated by an emergency involving safety of persons or property.   [PL 2003, c. 414, Pt. A, §2 (NEW); PL 2003, c. 614, §9 (AFF).]

"1.  Violation.  A person who violates this section commits a civil violation for which a fine of not less than $100 nor more than $500 may be adjudged.  

"2.  Repeat violations.  A person who violates this section after having been adjudicated as having committed 3 or more civil violations under this Part within the previous 5-year period commits a Class E crime." 

Notice the exceptions - if the use has been "authorized by the landowner" - I would take that to mean the owner of the land over which the ITS trail travels, not the land owned by the person who has the vehicle.   So he might be able to plow the road where it crosses his own property, but not the rest of the road.  And I don't think keeping the road plowed all winter for property access qualifies as an emergency.

Again, I would suggest Mediation as a less expensive method of resolution than court action.

Re: Message # 9892701

1. Regarding the subject Message, I believe there is nothing wrong with a statutory road association not having bylaws. It is up to the association, by affirmative vote, to agree not to have bylaws. My Road Association (RA) has about the same tenure (30 years) as yours along with 34 members and as of 2020 my membership has agreed throughout not to have bylaws. In place of bylaws we operate, at our RA Annual Meeting, to vote on each proposed action that is brought to the "floor". Affirmative actions, by majority voting, are accepted as "passed" and negative actions are not acted upon.

2. Plowing "soft" gravel roads has always been a problem; plowing a "frozen" gravel road is not that "bad" and can often be ignored. It appears that accommodating communication between the member that is plowing and other members who use snowmobiles should have been attempted early if at all possible. There is the question where, on the length of the road (beginning, middle or end) is the plowed cottage located. Less of the road being plowed may mean minimal damage which could more easily be repaired. Plowing a soft gravel road can easily mean that the road material will be moved to the side and can fill a ditch. A ditch that isn't working can easily destroy and eliminate passage on the road. If the road material has been plowed to the side perhaps the plow truck can use the plow to replace the material onto the main road surface after melting occurs. Plowing can also create what we Maine-iac's call "heater banks" or snow piled in a row (as a result of plowing) that prevents easy passage even by snowmobiles. The plow should try and eliminate any snow banks that prevent passage by anyone. The plow should try and, if possible, create snowmobile track entrances to assist the neighbors. Helping neighbors is always a good policy.

P.E.Dunn 1-25-2021

Peter, I agree that bylaws are not required, and that a road association can operate just fine by acting on things at annual meeting.  My one caution would be to follow atty John Cunningham's and atty Mary Denison's advice and put your "formula" for dividing the cost of repairs in writing.  But that could be done just as well at each annual meeting, so long as you remember to put it in writing each time.  There are advantages to not being stuck with bylaws that make sense at first but are later difficult to change.

Your tips for plowing are also all good.  I would add that if you can get the plow guy to put skids under his plow, that would allow him to leave a layer of snow on the road for the snowmobiles, while still making it passable by vehicles.  (As long as you don't get a big thaw, that is!)  My husband welded a couple of one foot lengths of cutting edge onto the bottom of the plow parallel to the ground at each end of the blade for it to skid on, so it would always slide instead of cutting into the dirt.  As a bonus, it meant his cutting edge lasted forever!

For years I used to give sleigh rides up and down our road in the winter.  Sometimes when we got the first snow we'd go out and drive up and down the road to make a packed base layer.  Then my husband was careful not to plow it too clean.  I can only remember one time when I had a group come for sleigh rides on a mild day late in the winter, and my husband actually had to take our big snowblower and blow some snow back into the road in spots where the sun had hit it.