The objective of vehicular ad-hoc network (VANET) is to create an available and reliable network for cars to communicate with each other and access Internet without pre-existing infrastructures. In this article we propose a novel routing protocol based on greedy perimeter stateless routing (GPSR) and roads information provided by maps to reduce packet loss rate causing by broken links. Simulations on Network Simulator 3 (NS3) showed our proposed protocol achieved maximum 13% increase in packet delivery ratio and maximum 34.3 ms decrement in transmission delay compared with GPSR. The performance of proposed method is much better than GPSR when car density is low.