线形设计是公路设计核心，它最终决定了公路的空间位置以及公路在驾驶员视觉中的反映。如何评价公路线形设计质量，目前在我国的标准或规范中尚无明确的定量指标。为此，本文从行车安全的角度对公路线形设计质量做了研究，提出了线形设计质量评价的量化标准。

Speed management is essential for ensuring the operating safety of highclassified highway. This paper discusses the setting, dissemination and implementation of speed limits based on the current state of speed management in China, and points out the concept of dynamic speed limits and the method of setting the dynamic speed limits according to highways characteristics, traffic volume, weather condition and accidents history. Finally, the paper puts an emphasis on the importance of traffic safety culture to the implementation of speed limits.

The generally road safety situation of highway net was evaluated through investigating road safety of some highways and analyzing accident patterns and causes. Some sections with high accident rate were found using road black spot identification technology. Then, accident causes related to highway features and traffic factors were analyzed. The characteristics of typical black spots were analyzed from the aspect of highway features and traffic devices. Running speed of vehicles on highways was measured in order to explain why over-speed driving always was primary accident cause.

以上海市罗山路工程为依托，在施工阶段逐层进行了测定，包括回弹弯沉、承载板测定路面当量回弹模量、各结构层底面应变状态等。通过测定数据的分析，研究半刚性基层沥青路面各结构层的贡献情况，对分析半刚性基层沥青路面结构的结构性能，进行路面结构的组合设计具有较大的参考价值。

In terms of traffic accident statistics in recent years sampled from a typical heavy transportation freeway in China and based on the field survey of vehicle operating speed on highway sections, the influence of heavy vehicles on freeway safety with regard to vehicle running theory, freeway environment and drivers' characteristic, and so on was studied. The research result shows that the main causes of accidents are related to driving performances, such as over-loading and significant speed variation among various types of vehicles. In view of this, the paper puts forward the corresponding measures for safety improvement from aspects of engineering and traffic management.