The governing body of any political or governmental subdivision or public corporation may enter into a written agreement with the department for the construction of a highway, structure, or appurtenance thereto, of greater width or capacity than would be necessary to accommodate highway traffic, upon any highway or connecting link within its boundaries and may appropriate from any funds available and pay into the Highway Cash Fund such sum or sums of money as may be agreed upon. Nothing contained in this section shall prevent any such governing body from constructing such highway, structure, or appurtenance of greater width or capacity independent of any contract with the department if such construction shall conform to such reasonable standards and regulations as the department may prescribe.