In this paper, we consider the problem of transmission delay in terms of finite coding length derived from the random coding bound for different cooperative protocols. Specifically, we first study the impact of cooperative transmission on the routing decision for wireless ad-hoc networks, where a routing optimization problem is formulated to minimize the end-to-end delay that ensures a satisfactory error performance. The closed-expression of the optimal solution is developed through the optimization problem and later used as quantitative criterion of routing decision. Furthermore, by considering the interference impact on system performance along a multi-hop routing, we then investigate performance gain on transmission delay for wireless cooperative networks by using a simple multi-user detection scheme, called overlapped transmission, in which multiple transmissions are allowed only when the information in the interfering signal is known at the receiver. As a result, both analytical and numerical results demonstrate the significant improvement on the system performance by using cooperative transmission with overlapping as well as the trade-off between the end-to-end delay and network throughput.