Data gathering or convergecast is one of the most popular applications of road side sensor network where the data sensed from the road are accumulated in the road side gateways or sinks for traffic monitoring purpose. The required delay sensitivity and reliability of the application as well as the scarcity of sensor resources make the task challenging. In this paper, a novel tree based data gathering scheme has been proposed exploiting the strip like structure of the road network. Sensor nodes are distributed in several virtual blocks along the road and a convergecast tree is constructed selecting one active node from each block. Implementation of efficient scheduling assures both the coverage and critical power savings of sensor nodes. The network connectivity is guaranteed throughout by the proposed tree maintenance module that handles the sensor node joining and leaving events. Simulation results show that the tree maintenance overhead in terms of both delay and control message communication is nominal. © 2013 IEEE.