Recent research shows that the traffic in public wireless networks is mostly transient and bursty. There is good reason to believe that ad-hoc traffic will follow the same pattern as its popularity grows. Unfortunately transient traffic generates route discoveries much more frequently than the well-studied long-term, constant-bit-rate traffic, causing network congestion problems for existing routing protocols. This paper describes the design of a new routing algorithm, called ECBR, that uses hybrid backbone routing in a manner that is well suited to workloads that include transient traffic. Our simulation results show that ECBR outperforms one of the main reactive algorithms (i.e., DSR). We also explain three key features of our algorithm and demonstrate their roles in substantially improving the performance compared to existing backbone routing techniques.