It　is　a　heavy　burden　for　a　driver　at　a　high　speed　to　understand　the　traffic　signs　accurately　and　completely.　The　more　information　on　a　single　traffic　sign,　the　lower　the　possibility　of　each　piece　of　information　being　understand.　In　order　to　discuss　the　correct　distinguishing　rate　of　drivers,　a　dynamic-emulation　experiment　was　carried　out.　The　traffic　sign　comprehension　of　more　than　three　hundreds　drivers　has　been　tested.　When　the　information　on　the　traffic　signs　increased,　the　correct　comprehension　rate　will　decrease　nonlinearly.　Especially　the　information　on　traffic　signs　is　above　three.　Therefore　the　drivers＇　maximum　receptivity　and　the　maximum　number　of　place　names　on　traffic　sign　is　given.　©　ASCE.