Under　the　context　of　intelligent　network,　vehicles　can　enact　cooperatively　at　a　small　headway,　and　continuous　connected　vehicles　will　be　in　platoon　configurations　by　information　interaction　of　vehicle-to-vehicle　or　vehicle-to-infrastructure　communication.　Thus,　the　road　capacity　will　be　improved　effectively.　Considering　the　traffic　flow　randomly　mixed　with　regular　vehicles　and　connected　vehicles,　4　types　of　car-following　characteristics　and　its　spatial　distribution　probability　in　heterogeneous　traffic　flow　were　analyzed.　Then　the　fundamental　diagram　model　and　the　passenger　car　equivalents　(PCE)　were　obtained.　And　the　sensitivity　analyses　on　penetration　rate　of　connected　vehicle　and　platoon　size　were　carried　out.　Research　results　show　that　the　improvement　of　the　penetration　rate　of　the　connected　vehicles　and　the　increase　of　the　platoon　scale　will　help　enhance　the　traffic　capacity　and　reduce　the　PCE.　Moreover,　the　positive　impacts　will　be　more　obvious　with　the　increase　of　the　penetration　rate　of　the　connected　vehicles.　When　the　vehicle　platoon　scale　is　larger　than　4,　its　impact　on　the　traffic　capacity　improvement　and　the　PCE　reduction　will　decrease　significantly.　©　2020,　Editorial　Department,　Journal　of　South　China　University　of　Technology.　All　right　reserved.