In this paper, we propose an intersection graph-based vehicular ad hoc network (VANET) architecture. Using the available electronic MAP and historical traffic statistics from public traffic databases, we create an intersection graph (IG) consisting of all connected road segments, which have shorter average inter-vehicle distances than the wireless transmission range, as its edges and intersections of these road segments as its vertices. We then calculate the least cost routing path in the IG. Hence, the source vehicle leverages the proposed IG and IG bypass routing protocols to greedily forward unicast packets to the destination vehicle via each intermediate intersection on the least cost IG path. Further, we also propose the IG routing path recovery process to handle the broken IG path in real-time. Finally, we execute NS2 simulations to exhibit that the IG and IG bypass routing protocols significantly outperform four wellknown VANET ones in terms of the average packet delivery ratio, end-to-end delay and hop count.