A sensitivity analysis was undertaken using a traffic flow micro-simulation program “SIM-R” to evaluate the effectiveness of “2+1 lane highway” sections、 which were built by adding an auxiliary lane to rural two-lane highways、 in a cold、 snowy region. The road surface conditions analyzed were dry and covered with compacted snow. As evaluation indicators、 average travel speed、 the percentage of following vehicles and the density of following vehicles were used. As a result、 the evaluation found that the installation of an auxiliary lane at certain intervals improved the level of service on two-lane highways. |