Multi-hop wireless networks formed between vehicles on a highway can provide Internet access to devices onboard vehicles if subsets of vehicles also share 3G/4G wireless connectivity to roadside base stations. In such a scenario mobile routers onboard vehicles should select the optimal gateway (base station) for Internet connectivity. This paper proposed an architecture that allows mobile routers to discover nearby gateways and select the optimal gateways based on various performance metrics. The architecture extends the Neighbour Discovery Protocol so that mobile routers can efficiently learn the identities and capabilities of gateways across multiple hops. A new gateway selection algorithm is presented; the algorithm can use multiple metrics, including gateway throughput, network load, path stability and financial cost, to determine the optimal gateway. Simulation results show that increase in application throughput of 10-20% can be achieved at the expense of small increase in signaling overhead. © 2012 Asian Network for Scientific Information.