This paper considers the extension of the Triber's intelligent driver model in case of vehicles movement on multilane highways. In contrast to previously proposed models, this model describes the process of lane changing in the maximum approximation to reality. This allows us to define additional delay in lane changing process, and expect the best match of the empirical data. Developed model was verified by simulation. Obtained results well correlate with data, which describes the effect of lane changing on the traffic flow.