通过对交叉口通行能力的主要研究内容、意义、影响因素分析等入手,着重研究了驾驶员的行为特性,指出驾驶员在临界点处具有3种行为特性,即,无视可变信息标志的行为,基于可变信息标志的完全行为以及基于可变信息标志的近似行为,并用数学关系对这三种行为规则进行描述.并由此,对上下两层均为十字交叉口型式的双层平面交叉口的通行能力公式进行了推导,为下一步研究和推广双层平面交叉口提供理论依据.“,”According to the analysis of the main contents,meaning and the effecting factor of traffic capacity of the crossing,the paper studied the behavior characteristics of drivers,and pointing out that drivers have three behavior characteristics,namely,behavior not based on variable message signs,behavior based on variable message signs,behavior not all peofectly based on variable message signs.These are then described with mathematics relation.In addition,a calculation formula of traffic capacity of the double-crossing was built up providing the theory foundation for studying and spreading the double-crossing.