Dramatic increase in road traffic volume has made driving safety and traffic efficiency more challenging, but smart transportation has been spotlighted as a promising technology for improving driving safety and efficiency. This paper surveys safe and efficient driving in the smart transportation with a focus on the aspects of systems, protocols, applications, and security, especially for autonomous vehicles. This smart transportation requires to monitor road surfaces precisely and identify hazards, and vehicles also need to share sensing information to avoid dangerous situations or environments through wireless communication in vehicular networks. For this purpose, dedicated short-range communications (DSRC) have achieved the international standards of the IEEE Wireless Access in Vehicular Environments (WAVE), and applications are now common that use the global positioning systems (GPS) for a dedicated navigation system navigator or smartphone application. This combination of vehicular networking and navigation enables systems and applications not only to enhance driving safety, but also to increase traffic efficiency. To support the vehicular systems and applications efficiently, the protocols need to be designed carefully and implemented effectively. This paper summarizes and analyzes the state-of-the-art research based on standardization activities for smart transportation systems, protocols, applications, and security. This paper also provides the comparison between the different technologies composing vehicular systems, protocols, applications, and security in terms of advantages, disadvantages, analysis, simulation, implementation, and complexity to provide a trend of overall technologies. Lastly, this paper suggests research directions for the smart transportation.

道路交通量的急剧增加使驾驶安全性和交通效率更具挑战性，但智能交通已被视为提高驾驶安全性和效率的有前途的技术。本文对智能交通中的安全高效驾驶进行了调查，重点关注系统，协议，应用程序和安全性方面，尤其是自动驾驶汽车。这种智能交通需要精确监控路面并识别危险，并且车辆还需要共享传感信息，以通过车载网络中的无线通信来避免发生危险情况或环境。为此，专用的短距离通信（DSRC）已达到车辆环境中IEEE无线访问（WAVE）的国际标准，现在，使用通用全球定位系统（GPS）的专用导航系统导航仪或智能手机应用程序和应用程序已经很普遍。车载网络和导航的这种结合使系统和应用程序不仅可以提高驾驶安全性，而且可以提高交通效率。为了有效地支持车载系统和应用程序，需要对协议进行仔细设计并有效实施。本文基于智能交通系统，协议，应用程序和安全性的标准化活动，对最新研究进行了总结和分析。本文还就优势，劣势，分析，模拟，实现，和复杂性，以提供整体技术趋势。最后，本文提出了智能交通的研究方向。