To　optimize　driving　behavior　and　improve　road　safety　on　expressways,　this　article　analyzes　the　effectiveness　of　existing　typical　diagrammatic　guide　signs　(DGSs)　on　urban　expressways　in　China.　A　driving　simulator　experiment　consisted　of　12　scenarios,　including　four　situations　of　guide　sign　installations　and　three　types　of　exit　ramps,　was　carried　out.　Four　indicators　were　analyzed　using　ANOVA　with　repeated　measures　and　a　post　hoc　test.　The　results　show　that　the　individual　effectiveness　of　DGSs　increased　the　instability　behind　the　signs　and　reduced　the　number　of　lane　changes　within　0　to　500　m　prior　to　the　destination　exit　in　left-turn　connectors　and　loop　ramps.　The　combined　effectiveness　of　DGSs　reduced　speeds　in　left-turn　connectors　and　loop　ramps,　especially　in　segments　near　interchange　exits,　and　lowered　the　rate　of　missing　correct　exits　in　right-　and　left-turn　direct　connectors.　In　conclusion,　DGSs　should　be　installed　with　advance　guide　signs.