Using　design　speed　as　a　primary　consideration　for　selecting　the　speed　limit　of　a　freeway　has　been　a　common　practice　since　the　opening　of　the　first　freeway　in　China　about　twenty　years　ago.　This　practice　has　been　widely　questioned　and　challenged　in　recent　years　by　the　public,　freeway　operators,　and　law　enforcement.　Speed　limits　solely　based　on　the　location　specific　design　speed　in　many　newly　completed　freeways　in　the　country　have　been　under　intensive　public　scrutiny,　particularly　at　locations　where　the　operating　speeds　are　much　higher　or　lower　than　the　speed　limits.　One　key　consideration　in　establishing　speed　limit　is　the　operating　speed　that　closely　relates　to　driver　behavior,　vehicles＇　mechanic　properties,　and　the　design　speed.　Driver　behavior　varies　greatly　by　factors　including　cultural　background　and　stage　of　economic　development.　Undoubtedly　different　social,　economic,　and　cultural　environments　contribute　to　significant　variation　in　driver　behavior.　The　methods　used　by　developed　countries　in　speed　limit　selection　may　not　be　suitable,　or　at　least　not　entirely　applicable,　to　situations　in　developing　countries.　Thus,　as　part　of　a　project　sponsored　by　the　Chinese　Ministry　of　Communication,　the　goal　of　this　study　is　to　investigate　the　relationship　between　speed　limit　and　operating　speed　in　different　freeway　environments.　The　principal　findings　from　the　study　are:　(a)　operating　speed　is　only　loosely　associated　with　speed　limit,　(b)　for　a　given　speed　limit,　the　average　speed　varies　greatly　depending　on　the　characteristics　of　the　location,　(c)　standard　deviation　of　operating　speed　distribution　on　freeways　in　China　is　generally　much　bigger　than　on　a　typical　freeway　in　developed　countries,　and　(d)　there　are　huge　speed　gaps　between　small　and　large　vehicles.　The　last　two　findings　represent　a　big　safety　problem　for　freeway　transportation.　The　combination　of　speeding　and　slow　running　vehicles　on　freeways　significantly　lowers　freeway　capacity,　as　well.　The　unique　speed　characteristics　observed　by　this　study　prompts　a　few　suggestions　on　speed　limit　and　speed　management.　©　2010　ASCE.