Haijian Li

Beijing University of Technology | Bei Gong Da · College of Metropolitan Transportation

As a novel traffic safety facility, the decorated sidewall in tunnels plays a crucial role in improving the safety and upgrading the driving environment. The design element spacing, frequency patterns and color, are important elements in the design of the tunnel wall decoration. In order to analyze the impact of the tunnel sidewall decoration eleme...

According to many studies, motor vehicle collisions lead to many deaths and disabilities, and bring about huge economic losses to societies and individuals around the world. If risky scenarios could be recognized and the driver could be timely warned, the frequency of traffic accidents could be reduced effectively, and traffic safety could be impro...

To ensure safety, it is necessary to test the connected vehicle (CV) technology before application. The goal of this study is to provide a case reference for the testing of the connected vehicle technology. The connected vehicle technology test platform is built based on the driving simulator. Taking fog zone, tunnel zone, and work zone as analysis...

Road traffic state estimation is an essential component of intelligent transportation systems (ITSs). However, road traffic state data collected by traffic detectors are often incomplete, which can cause problems across a variety of transportation applications, such as traffic state prediction and pattern recognition. We present GA-GAN (Graph Aggre...

The application of Deep Reinforcement Learning (DRL) has significantly impacted the development of autonomous driving technology in the field of intelligent transportation. However, in mixed traffic scenarios involving both human-driven vehicles (HDVs) and connected and autonomous vehicles (CAVs), challenges arise, particularly concerning informati...

The change of space environment at the tunnel entrance which the light changes from bright to dark will lead to frequent traffic accidents. To explore whether the connected vehicle environment will improve the driving performance and traffic safety at the tunnel entrance, this paper first of all designed a driving simulation experiment and provided...

The future trajectory prediction of heterogeneous traffic-agents for autonomous vehicles in mixed traffic scene is of great significance for safe and reliable driving. Thus, we propose the Multi-View Adaptive Hierarchical Spatial Graph Convolution Network (MVHGN) to predict the future trajectories of heterogeneous traffic-agents. Firstly, multiple...

The cooperative vehicle-infrastructure system (CVIS) offers opportunities to further enhance the potential of energy saving and emission reduction for eco-driving. However, it is still not clear about the effectiveness of CVIS on promoting eco-driving nor the multivariate effectiveness of CVIS designed for eco-driving on traffic flow and safety cha...

Car-following behavior is closely related to the longitudinal control of the vehicle, affecting the safety of the vehicle and traffic flow stability. In order to interact with the preceding vehicle, the target vehicle usually collects the driving data of the preceding vehicle. However, data acquisition devices often face malfunctions caused by vari...

The control of connected autonomous vehicles (CAVs) for cooperative sensing and driving in mixed traffic flows is critical for the development of intelligent transportation systems. However, the challenge lies in effectively representing and learning from the interactions between heterogeneous traffic agents, as well as the complex traffic states t...

Freeway bottleneck areas are prone to congestion and have high accident risk. A variable speed limit provides technical support for alleviating congestion and improving traffic safety in such areas. The existing variable speed limit rules in the related literature have a single focus, and most of them do not give specific quantitative speed limits....

It is necessary to identify takeover behavior patterns of conditional autonomous driving. In this paper, using driving simulations, takeover request lead time (5 s and 10 s) and nondriving-related tasks (working task and entertainment task) are designed to study the takeover behavior pattern in crash scenarios. Through driving simulation experiment...

The foggy freeway is a scenario with a high incidence of accidents. Different traffic flow conditions will affect the driving behavior of conditionally autonomous vehicle drivers in the foggy areas of the freeway. In this study, the experiment was carried out by using the driving simulation system. Forty-two participants drove on a foggy freeway ac...

To provide a better understanding of individual driver’s driving style classification in a traditional and a CV environment, spatiotemporal characteristics of vehicle trajectories on a road tunnel were extracted through a driving simulator-based experiment. Speed, acceleration, and rate of acceleration changes are selected as clustering indexes. Th...

The connected vehicle (CV) that integrates vehicle intelligence and communication network technology is one of the main methods to approach intelligent transportation, which is of great significance in solving the problem of road congestion and traffic accidents. As an important application field of CVs, multi-vehicle formation driving can realize...

Driving speeds are higher on freeways, and the visibility reduction occurring in freeway fog zones often increases traffic accidents. This study aims at assessing the impact of different levels of connected vehicle fog warning systems on driving behavior and safety. A connected vehicle fog warning system is developed based on driving simulators, an...

Exploring the influence of secondary task immersion duration on the take-over process is an important task in the research on conditional automated driving (SAE, L3). In this paper, with the tool of driving simulation, two different secondary task types and take-over request (TOR) times were designed for the ramp area take-over scenario. Forty-two...

This paper proposes a novel fuzzy comprehensive evaluation model based on the 2-tuple linguistic model and grey target decision method (2TL-GTD) for evaluating the comprehensive application effect of the connected vehicle system. Since the evaluation indicator system of the research problem belongs to multi-source heterogeneous data, the original d...

Short-term traffic states forecasting of road networks based on real-time data is an important component of intelligent transportation systems, especially advanced traffic management systems and traveller information systems. By considering the influence of both space and time dimensions, we proposed a novel GATs-GAN framework for the forecasting o...

Vehicle trajectory prediction is a challenging problem in the field of autonomous driving, witch is of great significance to the safety of autonomous driving and traffic roads. In view of the interaction between surrounding vehicles and target vehicle and its own trajectory, we propose a new graph network model to predict future vehicle trajectory....

Purpose This paper aims to use active fine lane management methods to solve the problem of congestion in a weaving area and provide theoretical and technical support for traffic control under the environment of intelligent connected vehicles (ICVs) in the future. Design/methodology/approach By analyzing the traffic capacities and traffic behaviors...

Purpose Heavy fog results in low visibility, which increases the probability and severity of traffic crashes, and fog warning system is conducive to the reduction of crashes by conveying warning messages to drivers. This paper aims at exploring the effects of dynamic message sign (DMS) of fog warning system on driver performance. Design/methodolog...

The drastic changes of the space environment at the tunnel entrance can lead to frequent accidents with higher levels. The connected vehicle environment provides drivers with surrounding traffic information and improve their driving behavior by helping them make safe decisions efficiently. As such, this study is to examine the effects of the connec...

As the merging section of an urban expressway main road and on-ramp traffic flow, on-ramp areas have serious merging conflicts. In the dynamic game between two streams of traffic flow, traffic congestion can occur and cause bottlenecks on expressways. With the development of vehicle intelligence and network technology, connected vehicles can form a...

Abstract In view of the benefits and a promising prospect of the emerging connected vehicles (CV), more and more vehicles will be equipped with the in‐vehicle human‐machine interface (HMI). This study aims to assess the comprehensive impacts of HMIs on individual driving performance, traffic safety, and eco‐driving behaviour based on a driving simu...

The accidents in the freeway are frequent and more serious on foggy days. Connected vehicle (CV) technology as a new technology can inform drivers of fog conditions in advance so the drivers can adjust their driving behaviors through Human Machine Interface (HMI) and Dynamic Message Sign (DMS) in the fog warning system. The level of driver's compli...

With the increase of vehicle ownership and the rapid growth of urban traffic, the problem of congestion in the off-ramp area of the main expressway has become the main factor restricting overall section efficiency and inducing traffic accidents. This paper focuses on the problem of group collaborative lane-changing behaviors of off-ramp vehicles an...

The traffic congestion in ramp areas is becoming increasingly prominent. In the upstream segments of ramp areas, effective management and control of lane-changing behaviors can improve the road capacity and make full use of the existing road resource. With the continuous development and application of connected vehicle technologies, lane-changing b...

Connected vehicle technology relying on Human Machine Interface (HMI) achieve a dominant position in the overall safety improvement. However, the impact of HMI on the driver’s visual attention cannot be ignored, especially on the accident-prone foggy freeway. The objective of this paper is to evaluate the level of distraction caused by HMI in data...

Raised pavement markers (RPMs) are among the common safety features of roads, playing an important role in preventing and reducing traffic crashes. RPMs are regarded as an effective measure for reducing the high crash rate and mortality in freeway tunnels in China. In this study, a driving simulator experiment was conducted to investigate the safet...

Emergency braking event of the vehicle in front is one of the main causes of forward collision. If the driver can sense emergency braking events of the vehicles in front timely, the coping behavior can be changed from passive visual stimulation to active coping behavior based on psychological expectation, which will greatly reduce the accident rate...

To explore the characteristics of mixed traffic flow with platoons of intelligent connected vehicles, a mathematical analytical expression that can reflect the random distribution characteristics of different types of vehicles in mixed traffic flow is proposed. Considering the dynamic characteristics of desired headway changing with speed, the car-...

To provide a better understanding of spatiotemporal characteristics of vehicle trajectories in connected vehicle environment, a driving simulation study was designed and conducted with an extra-long tunnel scenario. 35 drivers were recruited to participate in the driving experiment. To evaluate the spatiotemporal characteristics of vehicles with an...

To provide a better understanding of the effectiveness of the vehicle-road cooperative system on spatiotemporal characteristics of vehicles, especially in a tunnel road, this paper designed the human-machine interface of tunnel warning system based on the connected vehicle technology and carried out a driving simulation experiment. 35 drivers’ spat...

Crosswalk markings are a type of facility installed at the vehicle-pedestrian interaction locations and the function is to warn drivers to watch out for pedestrians crossing the street and improve safety for pedestrians. In Beijing, a type of new-designed crosswalk markings in China (NCMC) was installed. However, evaluating the effectiveness of thi...

Under the context of connected vehicle, vehicles can enact cooperatively at a small headway, and continuous connected vehicles will be in platoon configurations by information interaction of vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I) communication. Thus, the road capacity will be improved effectively. Focusing on the traffic flow r...

The development of connected vehicle technology enables the coordinated control of vehicle group behaviors. This article investigates traffic flow characteristics in on-ramp areas from two aspects: road geometry length and lateral spatial distributions of traffic flow. The upstream and downstream flow-balance strategies for each lane in on-ramp are...

To improve the efficiency of V2V, Efficient Clustering V2V Routing Based on PSO (Particle Swarm Optimization) in VANETs (CRBP) is proposed in this paper. First, vehicle nodes with identical moving directions are defined and the cluster heads are selected. Second, for the required routing optimization, the route particle and its velocity coding rule...

Connected vehicles have been shown to provide many benefits. The in-vehicle human-machine interface (HMI) can convey warning messages to drivers and help to adjust their driving behavior. This study investigated the comprehensive effects on individual driving performance, traffic safety, and eco-driving behavior with and without an in-vehicle HMI b...

Purpose The purpose of this study is to effectively optimize vehicle lane-changing behavior and alleviate traffic congestion in ramp area through the study of vehicle lane-changing behaviors in upstream segment of ramp areas. Design/methodology/approach In the upstream segment of ramp areas under a connected vehicle environment, different strategi...

This paper analyzed the stability of traffic flow mixed with connected manual vehicles, and the impact of different connected vehicle market penetration rate on maximum service flow rate. Based on the car-following characteristics, the car-following models of the connected vehicle and the regular vehicle were established and the general method of t...

With the development of sensor and network technologies, a type of hybrid sensor network (HSN) has been developed in traffic information acquisition systems. Sensor types in HSNs are diversified, mostly by batteries or solar energy as their energy source. Energy determines their lifetime. If energy consumption of sensors can be reduced from the asp...

Intersections are the key nodes in an urban traffic network that affect overall traffic efficiency. Lane width is a major element of an intersection that is affected by the saturation flow rate of the intersection. It is also influenced by a variety of other factors, such as road resource constraints, vehicle composition, traffic safety, and drivin...

With the change in people’s lifestyle and travel mode, understanding the individual and population mobility patterns in urban areas remains to an outstanding problem. Pervasive mobile communication technologies generate voluminous data related to human mobility, such as mobile phone data. To further study the characteristics of returning and explor...

In response to developing and/or diminishing foggy conditions, the variable speed limit application in a connected vehicle environment (CV-VSL) can estimate and deliver recommended travel speeds to individual drivers, which can help to reduce crashes when visibility conditions change. This study aims to quantify the effectiveness of the CV-VSL appl...

This work considers the winter Olympics events and takes the Xingyan Freeway as an example for application. A human-oriented connected vehicle system test platform considering driver adaptability was constructed for hardware-in-the-loop for human factors, and the influence mechanism of the comprehensive evaluation index under the connected vehicle...

This paper studies the effectiveness of fog warning systems on driving performance and traffic safety in heavy fog condition. A comparison study was conducted for four scenarios in heavy fog condition. First, a series of indexes corresponding to driving speed adjustments and surrogate measures of safety was obtained to explore the impacts that fog...

In order to study the impact of on-board unit ( OBU) on driving behaviors in vehicle to vehicle environment， human machine interface ( HMI) of the OBU and the V2V environment based on driving simulator was established and designed， then the simulated driving experiments were carried out and the vehicle driving state data of 4 simulation scenarios w...

Congestion has become a significant issue in recent years and has greatly affected the efficiency of urban traffic operation. Random and disorderly lane-changing behavior greatly reduces traffic capacity and safety. This paper is mainly concerned with the relationship of lane-changing spacing intervals provided by off-ramp facilities and traffic fl...

Traffic crashes pose a serious threat to global health and have negative impacts on social and economic development. Driving safety could be significantly improved if drivers obtained effective training based on practical suggestions from studies of the relationship between driver characteristics and driving safety. In this study, driver characteri...

Connected vehicle technology has potentials to increase traffic safety, reduce traffic pollution, and ease traffic congestion. In the connected vehicle environment, the information interaction among people, cars, roads, and the environment is significantly enhanced, and driver behavior will change accordingly due to increased external stimulation....

Several studies have researched the effect of dynamic message signs (DMSs) on the driving safety in work zones. However, only a few studies have examined the design of DMS control strategies in work zones. The purpose of this study is to investigate the effects of DMS control strategies on driving decisions and behaviors and to improve the driving...

This paper modeled and analyzed the queue length estimation mechanisms by different layout strategies. According to the lane allocations of intersections, several feasible layout strategies of magnetic sensors are proposed. Furthermore, a layout strategy with one single magnetic sensor is proposed to estimate the queue length. Specifically, three s...

An increased number of sensors used in traffic networks to obtain more information will lead to higher costs. This study proposes a minimum investment model for optimal traffic network sensor layout, which considers the spatial distribution characteristics of traffic information, homogeneity of various link locations, and total project costs. The m...

The development of autonomous vehicles provides effective solutions and opportunities for reducing the probability of traffic accidents. However, because of technical limitations and economic and social challenges, achieving fully autonomous driving is a long-term endeavor. One principal research question is how to choose the suitable driving mode...

The emerging of intelligent sensors results in the emergence and development of intelligent parking. Parking survey is one of the most important things for the parking managers and corresponding planners or researchers. We discuss the problem of making parking survey in intelligent parking systems where parking spaces, entrance and exit are detecte...

The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been...

To obtain adequate traffic information, the density of traffic sensors should be sufficiently high to cover the entire transportation network. However, deploying sensors densely over the entire network may not be realistic for practical applications due to the budgetary constraints of traffic management agencies. This paper describes several possib...

The accurate measurement of road traffic states can provide decision making for travelers and traffic managers. In this paper, an algorithm based on Kernel k-nearest neighbors (Kernel-KNN) matching of regional traffic attractors is presented to estimate road traffic states. First, the road traffic running states are divided into several different m...

Besides the vehicle factory performance, the driver's driving perception also influences on vehicle running characteristics which have been recognized in general. However the quantitative and empirical research through field experiments is still relatively limited. Based on the driving perception and the physical force analysis, the vehicle operati...

To estimate the intersection queue length, a magnetic sensor is deployed near the stop line at the intersection. Through the vehicle queue mechanism modeling, the evolution of vehicle occupancy sensor time and the departure interval can be obtained. Eventually, the queue length of the last signal cycle can be estimated. This paper analyzes the vari...

In many developing countries, mixed traffic is the most common type of urban transportation; traffic of this type faces many major problems in traffic engineering, such as conflicts, inefficiency, and security issues. This paper focuses on the traffic engineering concerns on the driving behavior of left-turning vehicles caused by different degrees...