To reduce the number of traffic accidents in highway tunnels, the causes for common accidents in tunnels are first analyzed, and corresponding strategies are summarized. Moreover, a coordinated technical framework of automatic driving (AD) and road in tunnel is established, based on 5G communication under the help of intelligent connected vehicles (ICVs), modern mobile communication, the Internet, and big data. Herein, innovative accident avoidance strategies based on this framework are discussed. This study agrees with the technical megatrend of ICV and AD and the objectives necessary to upgrade the quality of tunnel facilities. By improving the comprehensive warning mechanism in the tunnel area, the passive accident response can be replaced by active response, realizing intelligent traffic factors in the tunnel, improving the driving experience of humans, strengthening the emergency rescue capacity, and enhancing the risk management level.