The department may, whenever any money is appropriated by the general court for its use in the construction or improvement of any particular way, expend such money in constructing or improving the whole or such part of said way as it deems best, either upon the location of the existing way or upon any new location that may be established by the county commissioners or the selectmen, and no part of the way so improved shall thereby become a state highway or be maintained as such. The department may, however, lay out the whole or any part of any such way as a state highway.
Mass. Gen. Laws ch. 81, § 24