Gap　acceptance　is　the　main　parameters　of　intersection　capacity　and　safety　research.　Although　the　domestic　and　foreign　scholars　and　researchers　have　studied　the　critical　gap　deep　in　the　capacity　researches,　very　few　paper　has　been　discussed　the　process　of　gap　acceptance　from　the　view　of　traffic　safety　behaviors.　The　objective　of　this　paper　is　to　analyze　the　safety　behavior　of　gap　acceptance,　to　examine　the　relationship　between　gap　acceptance　behavior　and　waiting　time,　and　to　make　suggestions　of　safety　traffic　control　design　for　unsignalized　intersections.　The　authors　observed　1216　left-turn　gap-acceptance　behavior　samples　from　11　tee　type　of　unsignalized　Intersections,　which　are　two　ways　four　lanes　in　majors　and　two　ways　two　lanes　in　minors　(i.e.　4×2　T　Intersections).　It　is　found　that　some　drivers＇　gap-acceptance　behaviors　change　along　with　their　waiting　time.　It　is　also　found　that　the　precision　of　the　traditional　prediction　model　for　critical　gap　could　be　improved　if　waiting　time　is　considered,　which　implies　that　drivers＇　gap　acceptation　behaviors　have　much　to　do　with　drivers＇　waiting　time.　The　waiting　time　is　longer,　and　the　possibility　of　taking　risks　to　accept　the　small　gap　is　larger.　The　quantitative　model　was　also　developed　to　explain　the　relationship　between　values　of　accepted　gap　and　waiting　time.The　conclusions　of　paper　are　expected　to　be　useful　in　safety　control　design　and　discussing　safe　driving　behavior　for　unsignalized　intersections.　Copyright　ASCE　2007.