Controlling　speed　is　very　important　for　roadway　safety　since　speeding　increases　the　severity　of　crashes.　By　offering　the　highest　mobility,　freeways　are　more　vulnerable　to　fatalities　and　crashes　involving　injury.　How　to　effectively　control　operating　speeds　at　certain　freeway　sections　is　an　important　topic　in　China.　This　paper　presents　a　study　on　the　effectiveness　of　rumble　strips　on　freeways　through　a　user　survey　and　field　observation.　The　main　results　indicate　that　drivers＇　view　of　the　effectiveness　of　rumble　strips　on　freeways　is　inconsistent　in　different　regions.　By　analyzing　speed　before　and　after　rumble　strips,　this　paper　tries　to　estimate　the　impact　of　this　speed　control　device　on　speed　reduction.　©　2010　ASCE.