The　paper　considers　vehicles＇　multi-hop　connectivity　as　inter-grid　connectivity　and　draws　some　important　conclusions　by　theoretical　modeling.　Based　on　these　conclusions,　a　new　RSU　scheme　called　Pro_Dep　algorithm　is　proposed　which　tries　to　find　maximum　high　connectivity　grids　where　a　RSU　can　cover　more　coverage　area　at　a　given　minimum　connectivity　probability,　so　as　to　decrease　the　number　of　RSU　installment.　The　simulations,　which　come　from　traces　of　real　spatial　temporal　GPS　positions,　study　the　relationship　between　numbers　of　RSU,　number　of　grids　covered,　number　of　nodes　covered　and　minimum　required　connectivity　probability,　ratio　of　side　length　of　grid　to　vehicles＇　communication　range.　The　experiment　results　prove　validity　of　our　RSU　deployment　scheme.　©　2021　SPIE.