In WAVE/DSRC networks, traffic information dissemination is a critical application. Whenever a piece of information needs to be broadcast to vehicles within a specified range, not only RSUs in the range, but also most OBUs in the range, need to help broadcast/relay the information. In this paper, we identify out two problems in WAVE/DSRC networks. The first one is the interval mismatch problem. The second is the session-driven disappearing problem. Then we propose the dissemination algorithms to solve these problems. Furthermore, we also improve the backoff timer mechanism and then take the vehicular characteristics into considerations, including automobile types, relative speeds of vehicles, and traffic density. Finally, we verify our results by simulations and make conclusions.