换道规则对高速公路双车道交通流的影响

摘要

According tothe lane function andits use rights, lane−changing rules onfour−lanefreewayswere classified into four types,i.e.,symmetric, asymmetric, old−law andnew−law, which could bedescribeduniformly and reasonably through classified lane−changing motivations, i.e. intended and unintended. Based on the classifications,corresponding cellular automaton models were proposed,itssimulationwasrealizedthroughtheVC++programmingtaking into accountthe differences between carsand trucksin theirlength,themaximum speed andthemaximum acceleration. The results show thatcritical density andtruckspeed are independent of the lane-changing rules. The difference caused by different rules decreases with the increase of density andtruckratio. In the low and medium density range where the truckratio is small, compared with the symmetricrule,theotherthreerules can change the vehicle distribution by lane changing, which canreduce conflicts and increasecarspeedsignificantly.Carspeedunder the otherthreerulesis different only in the medium density range near the critical density where thetruckratio is small.%根据车道功能和使用权将四车道高速公路换道规则分为对称、不对称、旧法规和新法规4类，根据换道动机将换道分为有倾向型和无倾向型后，统一合理描述这4类规则。提出相应的元胞自动机模型，用VC++编程实现元胞自动机模拟，考虑快车(小客车)和慢车(大货车)的长度、最大速度和最大加速度差异。研究结果表明：临界密度和慢车速度都与换道规则无关；不同换道规则造成的差异随着密度和慢车比率的增大而减小；在慢车比率较小的中低密度区，与对称规则相比，其他3种规则通过换道改变车辆分布，可大幅度减少冲突，提高快车速度；其他3种规则下快车速度仅在慢车比率较小且靠近临界密度的中密度区存在差异。