To　formulate　efficient　emission　reduction　policies,　we　explore　the　driving　forces　of　CO2　emissions　from　the　transport　sector　of　four　municipalities　in　China　during　2000-2017　based　on　the　temporal-spatial　decomposition　analysis　model.　The　key　factors　causing　the　differences　in　CO2　emissions　will　be　investigated　in　important　years　(i.e.,　2000,　2005,　2010,　and　2017).　Two　main　results　are　found:　(1)　Energy　intensity,　as　well　as　transportation　intensity,　is　the　dominant　restraining　factor　confronting　the　transport　sector＇s　CO2　emissions,　while　the　income　effect　is　reversed.　(2)　The　results　of　the　analysis　further　show　what　drives　different　emission　levels　(e.g.,　income　effect,　energy　structure,　and　transportation　structure)　and　four　municipalities　have　greater　potential　in　the　reduction　of　CO2　emissions.　We　further　discuss　the　root　causes　of　the　spatial-temporal　differences　in　carbon　emissions　in　the　transport　sector　and　analyse　their　future　trends　in　detail.　Based　on　this,　we　propose　to　pay　attention　to　strengthen　coordinated　emission　reduction,　optimize　the　transportation　mode,　adjust　the　energy　consumption　structure,　and　select　emission　reduction　strategies　according　to　local　conditions.　In　addition,　emission　reductions　in　the　transportation　sector　are　also　affected　by　various　factors　such　as　social　systems　and　transformation　costs,　and　further　research　is　needed　in　the　future.