Joint deployment of exclusive bus lanes and limited access bus lanes in a transportation network

Providing exclusive right-of-way to buses is considered an effective measure to enhance the transit system’s performance. However, the conversion of a General-Purpose Lane (GPL), which is shared by all transportation modes, to an Exclusive Bus Lane (EBL), reduces the available capacity for auto users and may result in an underutilized lane known as the empty syndrome lane. To address this deficiency, it is suggested that a special class of vehicles, such as High Occupancy Vehicles (HOVs) be permitted to drive in EBLs, but they may be required to pay tolls. This type of lane is called a Limited Access Bus Lane (LABL) and is designed to prioritize public transportation and restrict the entry of HOVs in bus lanes. The goal is to ensure transit passengers do not experience a decrease in the quality of service. This paper compares the results of four bi-level optimization models used to determine the optimal location of different combinations of special-use lanes in the network, namely: 1) only EBLs; 2) joint deployment of EBLs and HOV lanes; 3) joint deployment of EBLs and tolled HOV lanes; and 4) joint deployment of EBLs and LABLs. A base optimization problem is developed for the last proposed scheme (i.e., joint deployment of EBLs and LABLs), and the formulation is modified to solve three other network design problems. The proposed model is solved by applying a genetic algorithm. To analyze the suggested framework, a numerical test is conducted on the Sioux Falls network as a medium-sized network and the network of Zanjan as a real-sized network. Furthermore, by analyzing the numerical results of the four optimization problems, this study highlights that the joint deployment of EBLs and LABLs outperforms the other three schemes in terms of transit users’ travel time and the average volume capacity of bus routes.