A　rectangular　hybrid　automata　model　of　a　four-phase　intersection　is　given,　in　which　the　queue　lengths　are　considered　as　continuous　variables　to　represent　the　vehicle　flow　behavior　of　the　intersection　and　the　discrete　event　part　represent　the　traffic　light　behavior.　Based　on　the　rectangular　hybrid　automata　model,　all　directional　vehicle　flows　are　analyzed.　A　method　for　reachability　analysis　of　rectangular　hybrid　automata　is　applied　to　analyze　the　maximum　and　minimum　of　each　queue　length　of　the　single　intersection.　Simulation　completed　with　the　help　of　the　toolbox　CheckMate　shows　that　the　rectangular　hybrid　automata　model　and　the　method　can　not　only　perfectly　represent　the　hybrid　character　of　the　dynamic　traffic　flow　of　the　single　intersection,　but　also　can　verify　the　efficiency　of　the　timed　scheme　of　the　traffic　light.