Found this. Looks like you might need a lawyer with experience in land court, a land surveyor, and money.

The status of a “way” must be addressed on a case-by-case basis, but in most cases a way that was laid out as a street but never constructed (often referred to as a “paper street” because it shows up on plans but does not appear on the ground to be a street) is not even owned by the Town. Unless they were specifically laid out or accepted as public ways by Town Meeting (or more recently by the Mayor and Council) they were probably created years ago when an owner of a large tract of land divided the land up into lots and streets, then sold off the lots without ever retaining a specific deed to the streets. Many of the streets were constructed and became public ways or were left private ways open to public travel. To resolve the issue of ownership of undeeded private ways, the State Legislature passed laws that essentially say that an undeeded private way is owned to the centerline by the abutters but cannot be altered to prevent it’s use for roadway purposes. The laws pertain to the unconstructed ways as well. So the answer in many cases is that you already own to the center of the street, but you can’t do anything on the property that would prevent it from being used for roadway purposes. The way to eliminate those restrictions on the property is a long and expensive process through the Massachusetts Land Court where the court will require that others with rights to use the land for roadway purposes be identified and that the court be satisfied that they no longer need those rights.