The board of county commissioners of each county in the state are authorized to cut all hedge fences, trees and shrubs growing upon the highway right of way or on right of way boundary, within three hundred fifty (350) feet of a railroad grade crossing or abrupt corner in the highway, and thereafter keep the same trimmed to provide clear vision, and to cut all weeds in the highways and thereafter keep the same cut so that the same shall not at any time be allowed to grow to a height obstructing clear vision; to remove all signboards, billboards, and board fences obstructing clear vision within three hundred fifty (350) feet of any such railroad crossing or abrupt corner in the highway: Provided, That nothing in this act shall apply to signs placed by any county or state association for the purpose of imparting historical information or traveling directions: Provided, however, That the board of county commissioners of any county in this state are hereby authorized to cause the removal of any hedge along any road in their respective counties, when in their judgment they, having first made suitable investigation of conditions, such hedge should be removed. The county may pay all expenses incident to removing such hedge out of the state and county road fund when applied to state and county roads and out of the county and township road fund when applied to county and township roads.