Traditionally,　a　signalized　intersection　capacity　can＇t　be　discussed　without　putting　signal　timing　into　consideration.　In　general,　signal　timing　includes　determination　of　cycle　length,　number　of　phases,　green　interval,　yellow　time　and　all　red.　A　result　capacity　varies　with　changing　of　parameters　in　signal　timing.　This　is　the　traditional　way　of　estimating　capacity,　named　timing-based　capacity　calculation　approach.　However,　at　the　planning　stage,　if　planners　or　decision　makers　want　to　find　out　the　future　conditions　of　the　network　they　have　planned,　they　need　to　evaluate　the　performance　in　terms　of　v/c　ratio　because　of　undetermined　capacity　of　intersection.　A　new　concept　of　so-called　＇equilibrium-right-of-way　based　capacity＇　is　introduced　in　this　paper　to　overcome　this　difficulty.　This　capacity　is　purely　based　on　the　geometrics　of　an　intersection　(number　of　lane　and　lane　allocation)　rather　than　the　signalization.　The　purpose　for　introducing　this　concept　is　to　assume　capacity　of　an　intersection　to　be　a　sole　value　when　the　geometrics　of　the　intersection　are　set.　Uniqueness　of　capacity　for　interrupted　flow　facility　should　be　the　key　of　capacity　studies.　With　this　concept,　capacity　formula　based　upon　the　equilibrium-right-of-way　is　developed　to　estimate　the　capacity　of　signalized　intersections.　The　result　from　this　study　is　great　significance　for　the　development　of　capacity　analysis,　particularly　for　the　interrupted　flow　facilities.　©　2012　American　Society　of　Civil　Engineering.