It　is　foreseeable　that　connected　vehicles　(CVs)　and　regular　vehicles　(RVs)　will　be　operated　together　on　roads　in　the　upcoming　decades.　The　appearance　of　CVs　provides　us　an　opportunity　to　improve　traffic　efficiency　by　guiding　drivers　to　properly　steer　their　CVs.　To　take　advantage　of　this　opportunity,　this　paper　proposes　two　cooperative　driving　strategies　for　CVs　that　move　in　heterogeneous　RV　and　CV　traffic,　namely,　CDS-L　and　CDS-G.　CDS-L　is　a　local　strategy　that　considers　only　the　traffic　surrounding　the　subject　CVs.　CDS-G　is　a　global　strategy　that　considers　the　conditions　of　all　CVs　on　a　road.　The　basis　of　the　strategies　is　to　incorporate　the　spatial　and　temporal　averages　of　the　driving　status　of　surrounding　CVs.　A　parameter　that　is　a　function　of　the　traffic　density　is　introduced　to　balance　traffic　efficiency　and　fluctuations.　Simulation　results　demonstrate　that　the　proposed　strategies　well　suppress　traffic　fluctuations　and　thus　promote　traffic　efficiency.　The　proposed　strategies　are　dedicated　to　traffic　congestion　mitigation　by　using　low-level　configuration　CVs.