In this paper we researched about different ad hoc routing protocols for VANET. The main aim of our study was to identify which ad hoc routing technique has better execution in highly mobile environment of VANET. To measure the performance of routing protocols in VANET, we considered two different situations i.e. city and highway. Routing protocols were selected carefully after carrying out literature review. The selected protocols were then evaluated through simulation in terms of performance metrics i.e. throughput and packet drop. From results, we observe that A-STAR shows better performance in form of high throughput and low packet drop as compare to AODV and GPSR in city environment, while GPSR shows better performance as compare to AODV in both highway and city environment of VANET.