Optimal control method of freeway based on tollbooths lane configuration and variable speed limit control

Abstract

There are tollbooths on some freeway ramps, and toll lanes can be divided into Electronic Toll Collection (ETC), Manual Toll Collection system (MTC), ETC/MTC hybrid toll lanes and closed. The traffic capacity of different lanes is different. Different lane combinations are set to adjust the traffic flow of the ramp into the main line. Therefore, this strategy can be regarded as a kind of ramp metering (RM). This paper presents an optimal control method for freeways based on tollbooths lanes configuration and variable speed limit (VSL) control. Firstly, cellular automata model and cell transmission model are used to describe the operation of toll plazas and main line traffic flow respectively. Furthermore, the freeway control methods are constructed by using tollbooths RM (TB-RM) and TB-RM combined with main line VSL control respectively to improve the freeway traffic operation efficiency. Finally, the proposed method is simulated experimentally. Results from simulation experiments demonstrate that the proposed method (i) significantly improves the traffic performance in terms of total time spent savings; (ii) observably enhances driving safety.