With the approval of the governor and council the commissioner of transportation is hereby authorized to classify as a class I highway any existing or proposed public highway which is needed to provide essential highway transportation services from a military reservation or defense industry or activity to suitable transportation facilities.
RSA 228:51
RSA 229:23. 1961, 87:3. 1981, 87:1. 1985, 402:6, I(b)(1).