Abstract: As the upper limit of running speed，expectation speed is the key parameter of the running speed forecasting. In view of current problem that the expectation speed is excessively high in running speed prediction of double － lane road，the relationship between road conditions and drivers’choice of expectation speed are focused; the survey method is used to quantify the effect of road conditions on the expectation speed，which improves the prediction method for expectation speed of double-lane road，and lays a good foundation to test the alignment safety of double － lane road by using driving speed.

Key words: double － lane road, expectation speed, alignment, traffic environment

摘要： 期望车速作为运行速度的上限，是运行速度预测的关键参数。针对当前双车道公路运行速度预测中期望车 速过高的问题，着重分析了道路条件与驾驶员期望车速选择的关系，并采用调查统计方法，量化道路条件对期望车 速的影响程度，完善了双车道公路期望车速的确定方法，为利用运行速度检验双车道公路的线形安全性奠定了良 好基础。

关键词: 双车道公路, 期望车速, 线形, 交通环境