§ 156. Penalty, and notice on bridge. The town superintendent may fix and prescribe a penalty, not less than one or more than five dollars, for riding or driving faster than a walk on any bridge in his town whose chord is not less than twenty-five feet in length, and put up and maintain in a conspicuous place, at each end of the bridge, a notice in large characters, stating each penalty incurred. Whoever shall ride or drive faster than a walk over any bridge, upon which notice shall have been placed, and shall then be, shall forfeit for every offense, the amount fixed by such town superintendent, and specified in the notice.