With　the　development　of　technology,　platoons　of　intelligent　and　connected　vehicles　(ICVs)　will　join　regular　vehicles　on　roads,　and　the　characteristics　of　the　traffic　flow　will　change　accordingly.　In　this　paper,　the　traffic　flow　configurations　and　the　spatial　distributions　of　various　types　of　vehicles　are　analyzed,　when　the　mixed　traffic　flow　is　in　equilibrium.　To　model　the　mixed　traffic　flow　with　platoons　of　ICVs,　the　intelligent　driver　model　and　the　PATH　laboratory-calibrated　cooperative　adaptive　cruise　control　model　are　introduced　for　capturing　the　car-following　behavior　in　this　study.　Then,　analytical　methods　for　the　stability　and　the　fundamental　diagram　models　of　mixed　traffic　flow　are　developed.　The　results　of　the　sensitivity　analysis　demonstrated　that　ICVs　can　improve　the　stability　of　the　mixed　traffic　flow　under　a　critical　speed.　However,　if　this　critical　speed　is　exceeded,　an　increase　in　the　number　of　ICVs　may　degrade　the　stability　of　the　mixed　traffic　flow.　Moreover,　this　critical　speed　decreases　as　the　maximum　platoon　size　increases.　In　addition　to　stability,　the　results　suggest　that　ICVs　can　effectively　improve　traffic　capacity.　Moreover,　the　study　results　demonstrate　that　a　decrease　in　the　desired　time　headway　and　an　increase　in　the　maximum　platoon　size　are　advantageous　for　the　efficiency　of　the　mixed　flow.　(C)　2020　Elsevier　B.V.　All　rights　reserved.