Social force model is a classical model in crowd simulation. Since it was proposed in 1995, the model has been widely used and modified. In 2000, the concept of panic degree was added to the model to propose an improved version. Although many studies focus on social force model, there are few studies on this concept. Therefore, some key parameters and the concept of panic degree in the social force model were analyzed, and the change of panic degree was used to explain the phenomenons of "fast is slow" and "herd behavior" in crowd evacuation. To overcome the problem in the original model:very few pedestrians may not follow others or may not evacuate at the exit in some conditions caused by the not detailed enough description of pedestrian perception in social force model, the visual field range description of the pedestrian was added and the self-motion state for the pedestrian was redefined and other methods were performed to optimize the social force model. Experimental results show that the improved model can simulate the crowd's herd phenomenon well and is helpful for understanding the concept of panic degree in social force model.

Focusing on the problems in bus priority systems, like hysteresis, being not able to fully exploit road capacity, an Adaptive Bus Priority (ABP) model based on the Internet of Vehicles (IOV) was proposed. First, with powerful communication capability of IOV, using time division multiplexing idea, road multiplexed control rules for ordinary bus was designed, and the "space priority" was achieved by setting a virtual bus lane. Secondly, real-time data acquisition of arrival vehicle was used to replace the historical data to solve the problem of hysteresis. Finally, the bus priority signal control model was designed, and bus priority was realized by inserting short phases to make public transit priority. VISSIM software was used to design simulation experiment to compare the ABP model and the traditional model. Simulation results indicate that the ABP model can improve the operation efficiency of bus and intersection pass capacity without causing great impact to social vehicles.