An　effective　way　to　optimize　traffic　structures　is　by　changing　travel　costs,　thereby　moving　travelers　from　private　transportation　to　public　transportation.　However,　according　to　the　existing　studies,　the　traveler　will　not　transfer　from　one　mode　to　another　unless　the　change　in　travel　utility　is　greater　than　the　indifference　threshold.　Therefore,　the　＂indifference　threshold＂　is　one　of　the　most　important　factors　influencing　a　traveler＇s　choice　of　behavior.　This　study　defines　the　＂indifference　threshold＂　as　the　traveler＇s　sensitivity　to　changes　in　travel　utilities.　In　the　framework　of　the　theory　of　planned　behavior　(TPB),　a　structural　equation　model　(SEM)　considering　the　indifference　threshold　is　established　to　analyze　a　traveler＇s　mode　choice　behavior.　The　analysis　results　showed　that　a　travelers＇　sensitivity　to　changes　in　travel　utilities　has　the　greatest　impact　on　mode-choice　behavior　intentions　and　mode　choice　behavior.　Perceptual　behavior　control　has　the　strongest　influence　on　travel　choice　behavior.　In　addition,　in　order　to　further　explore　the　heterogeneity　of　a　traveler＇s　behavior,　the　travelers　were　subdivided　into　four　types,　by　establishing　a　latent　class　model　(LCM)　considering　the　indifference　threshold.　Finally,　different　traffic　management　suggestions　are　proposed　for　different　types　of　travelers.