Some previous works had proposed some replication-based routing protocols,such as epidemic routing,but they couldn't achieve high delivery ratio at a low delivery cost. This paper designed an adaptive replication-based routing protocol called ARR for efficient routing in vehicular networks. ARR was a fully distributed protocol. The goal of ARR was twofold,first,ARR deliverd the majority of the messages generated in time-to-live; second,ARR introduced as little delivery cost as possible. To achieve high deli...