In order to study the effect of crossing pedestrians on traffic performance at crosswalk without signal control, the work develops a game theory-based description of pedestrian–vehicle interactions, considering the decision-making uncertainty. The hybrid strategy of the game is obtained. The relevant parameters of the game model are calibrated by collected video data. The cellular automaton simulation system composed of a two-way four-lane traffic flow and pedestrian flow is constructed with the game model imbedded for identifying the effect of crossing pedestrians on traffic performance. The influencing factors are identified with their correlation analyzed by numerical simulation of different traffic conditions. According to the simulation results, the arrival rate of pedestrians has a great impact on traffic volume and pedestrian delay. The severity of conflicts between vehicles and pedestrians is classified and the causes are identified by analyzing the arrival rate of pedestrians and vehicles, respectively, and their relationship between one another. In addition, the threshold of traffic flow and pedestrian flow causing traffic conflicts and delay is proposed, also including the threshold of pedestrian arrival rate which will induce force crossing behaviors. The results show that the proposed model reconstructs the traits of traffic and pedestrian flow and their conflicts phenomenon at crosswalks. It provides some practical references for transportation agencies to meet pedestrians time-cost and comfort needs in crossing streets when they design pedestrian crossing facilities.

This paper presents a real-time dynamic path planning method for autonomous driving to avoid collision with crossing pedestrian on branch streets. The velocity obstacle algorithms are introduced to pick up the collision-free velocities for vehicles. In this method, the curvilinear lane edges are considered as static obstacle while crossing pedestrians and approaching vehicles are considered as velocity obstacles. The paths planning of vehicles are optimized by considering the delay minimum and comfort of drivers under the constraints of appropriate parameters for veer, throttle, or brake systems. A single vehicle's path planning and multi-vehicles 'coordinated or uncoordinated paths planning with crossing pedestrian collision avoidance are experimentally simulated including the longitudinal and lateral motions planning of vehicles. The simulation results demonstrate the effectiveness of the proposed method and indicate its wide practical application on autonomous driving to improve the traffic safety of branch streets. INDEX TERMS Autonomous vehicle, path planning, velocity obstacle, optimal control.

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Emerging connected autonomous vehicle (CAV) technologies provide an opportunity to the vehicle motion control to improve the traffic performance. This study simulated and evaluated the CAV-based speed and lane-changing (LC) control strategies at the expressway work zone in heterogeneous traffic flow. The control strategies of CAV are optimized by the multi-layer control structure based on model predictive control. The heterogeneous traffic flow composed of human-driven vehicles and CAVs is constructed based on cellular automata by the proposed Expected Distance-based Symmetric Two-lane Cellular Automate (ED-STCA) LC model and CAV car-following model. The six control strategies composed of variable speed limits (VSL), LC and their coordinated control strategies are experimented. The average travel time and throughput are selected to assess the advantages and disadvantages of each strategy under each combination of vehicles’ arrival rates and CAV mixed ratios. The numerical results show that: (i) the effect of the control strategy on the traffic is not obvious under free flow, and the control strategy may worsen the traffic under medium traffic. (ii) Early lane-changing control (ELC) is better than late lane-changing control (LLC) under medium traffic, and LLC is better under heavy traffic. (iii) [Formula: see text] is the best choice under heavy traffic and the mixed rate of CAVs is high. The simulation results obtained in the paper would provide some practical references for transportation agencies to manage the traffic in work zone under networking environment in the future.

VMS project works as an essential component in ITS traffic information offering system. The paper reviews main international literatures of impact evaluation on VMS, points out issues existing in the past researches, analyzes socio-economic benefits produced by VMS and offers calculating models. Based on analysis in different evaluation methods, the paper applies benefit-cost analysis method, in an effort to show that socio-economic impact evaluation for VMS should begin with the control strategy of VMS, and subsequently technology evaluation, because above them are design and technology bases of VMS. Socio-economic impacts or benefits are reflected through its effects on traffic system and broad society and environment. The approach to identify VMS 's socio-economic impacts in traffic network system is applicable to explore potential or indirect benefits of VMS, especially to evaluate integrative impacts among VMS and other components of traffic information offering system for ITS.