In this paper we propose an improved adaptive media access (MAC) layer routing algorithm for the broadband power line communication (BPLC) access network founded on the fixed basic approach routing algorithm, which is integrated within the IEEE P1901 standard. The proposed adaptive algorithm incorporates a new dynamically scaled threshold for the selection of the next hop station based on the information from the physical layer. Furthermore, the procedures for the route and the time allocation modifications during the connection setup and later adjustments are developed. Simulation of the new adaptive and existing fixed routing algorithm is performed on the model of a realistic BPLC network using the OMNeT++-based BPLC cross-layer simulator BPlcSim. The simulation results showed that the adaptive routing algorithm outperforms the fixed routing in all aspects, since each station can perform routing functions and make the selection of the most reliable next hop station.