The optimization should consider BRL-15572 5-HT Receptor Antagonists and Agonists the interactions of the design parameters, like the length of sorting area, signal timing plan, lane allocations, and traffic demand. The driving behaviors in the pre-signal system will be different from those in the road section and conventional intersection approach, which should be taken into account by the selected evaluation method. 2.2. Methodology and the Proposed Framework The major function of the sorting area is to reorganize vehicles. Though it is an area where multiple trajectories interact with each other, there

still exist specific patterns for corresponding driving behaviors. If the driving behavior during the process of lane changing was calibrated, the trajectories of the specific movement can then be obtained. We can indicate that the capacity of the sorting area only decreases at the location where vehicles accomplish the lane changing action, like the weaving area. If there is a way to describe the space that the vehicle actions (like lane changing) needed in the

sorting area at specific status, it can become the foundation for the geometric design of the pre-signal system. For instance, considering the maximum longitudinal distance needed for lane changing and the queue length, the minimum length of the sorting area can be obtained. For safety and economic reason, we cannot evaluate the performance of various geometric designs of sorting area. In this way, the simulation based optimization is frequently utilized. The cellular automaton (CA)

model is then selected to describe the usage of temporal and spatial road resources and evaluate the efficiency of pre-signal system. The CA model is improved by modifying the vehicle description and adding turning-deceleration rule and lane changing rule. All the corrections to the CA model are based on the field observed driving behavior data. By knowing the position of each vehicle in the sorting area at every time stamp, the range of the optimal length of the sorting area can be obtained by determining the maximum capacity of the intersection approach. The framework of the optimization is shown in Figure 3. Figure 3 Framework of the optimization of pre-signal system. 3. Calibration of Driving Behaviors 3.1. General Driving Behaviors The driving behaviors can be divided into longitudinal driving behavior and horizontal driving behavior Cilengitide according to the vehicle motion state. The longitudinal driving behavior mainly refers to the car following model, which is well documented [14]. Lane changing is the major horizontal driving behavior at the intersection approach. Controlled by the pre-signal, lane changing behaviors for a specific movement will be different from the common pattern. These vehicles may change lanes more than once to reach the target lane.