Cooperative vehicle infrastructure system(CVIS)is one of the advanced solutions to enhance intersection vehicle passage safety.Due to the lack of clear specifications and standards regarding the dynamic timing and transition processes of system object state interaction in existing CVIS technologies,ensuring the safety of passage control logic is challenging.This study utilizes formal language to describe the functional logic of CVIS in unsignalized intersections,verifying the safety of system object state interaction and control logic to improve vehicle passage safety at unsignalized intersections.Simulations are conducted for scenarios including single-vehicle non-conflict,dual-vehicle conflict,and multi-vehicle conflict to identify state interactions and enable transition paths.By integrating tools and requirement specification statements for system safety attribute verification,the reliability and safety of control logic are demonstrated,providing a credible basis for developing high-security architecture for CVIS.

The rapid development of urban roads has resulted in an increase in the amount of information that needs to be displayed on traffic signs. The overloading of information on traffic signs may increase drivers' visual cognition burden and cause driving errors. It could be an important factor affecting driving safety and result in accidents. To enable drivers to cognize traffic signs, the information density that they could endure under reasonable workload levels should be determined. In this study, we designed and implemented trials to analyze drivers' visual working memory load (VWML) caused by different information densities (including stimulus intensity (SI) and interval time of stimulus (IS)) of traffic signs. Twenty-four paid participants (12 females) with a mean age of 23.38 years (SD = 1.38) participated in laboratory simulation trials based on the memory retrieval approach. Subjective ratings (rating scale mental effort (RSME)), and performance measurement based on reaction time and accuracy of information-matching task were measured to reflect drivers' VWML at different information densities. The results show that information density is an important factor affecting drivers' VWML. The following are the significant observations of the study: (1) The subjective ratings on mental effort increased with increase in the SI. Meanwhile, it first decreased and then increased with increase in the IS. (2) The response accuracy results show that a high accuracy (>= 0.7) was achieved by drivers in an IS of 15 s when the SI was at most 14.16 bit/m(2). Correspondingly, the drivers underwent less mental workload as a result of their better short-term memory characteristic. (3) The mean reaction time was over 1800 ms when the SI was over 14.16 bit/m(2). This indicated a reduction in the information-processing capability of the drivers. The results indicate that cognition of information of unreasonable density on traffic signs would increase drivers' VWML. This would, in turn, result in an increase in their reaction time and decrease in accuracy. The threshold of information density was also determined through the experiment. It would satisfy the information demand of drivers and prevent information redundancy. The results contribute to an understanding of drivers' VWML while cognizing traffic signs with different information densities and provide safety, effectiveness, and information continuity considerations for the design and setting of traffic signs.

Bus guidance information supplied by advanced traveler information systems provide a reference for route selection by bus passengers. This study analyzes the interaction between bus passengers’ route-choice behavior and the relationship in a game. The game revenue of the passengers waiting on the bus platform is quantified by parameters such as the number of passengers waiting on the platform, the number of passengers on the bus, and the passenger capacity of the bus. Based on the characteristics of passenger-bounded rationality, an evolutionary game model of bus choice behavior under information-induced conditions is established. Through the evolutionary game model, the distribution of the proportion of passengers receiving the guidance strategy is obtained when the evolution is stable. Finally, according to the distribution results, the passenger guidance strategy is discussed to achieve a win-win situation between passengers and bus operators.

Because the strategy of stopping bus lines during an epidemic can negatively impact residents, this study proposes a bus passenger flow control model to optimize the safety of and access to bus transport. The information interaction environment can provide a means for the two-way regulation of buses and passengers. In this model, passengers first request their pick-up and drop-off location, and then the bus feeds back information on whether it accepts the request. Through this method, passenger flow control can be realized through complete information interaction. The study aimed to establish a multi-objective function that minimizes the weighted total cost of the safety cost, the passenger travel cost, and the bus travel cost during an epidemic. The constraints were the full load and riding rates of urban buses in peak periods under the condition of epidemic prevention and control. The results showed that, in the morning peak period, the passenger flow control scheme reduced the passenger infection probability by 17.89%, compared with no passenger flow control scheme. The weighted total cost of the epidemic safety cost, the passenger travel cost, and the bus operation cost was reduced by 8.04%. The optimization effect of the passenger flow control scheme of this model is good, and not only reduces the probability of passengers being infected, but also meets the requirements of epidemic prevention and the travel needs of residents.

The work zones greatly change the traffic wave characteristics on the urban road and further significantly influence the signal timing schemes. However, studies on the traffic wave under the influence of work zones are limited. This paper attempts to investigate how a work zone changes the traffic wave propagation characteristics. The traffic wave profiles for different scenarios are analyzed to explore the propagation characteristics of the traffic waves. Then the novel models for the various traffic waves are proposed. Furthermore, a real case study is conducted to evaluate the performance of the proposed models. The study indicates on the road with the work zone, the lane-blockage phenomenon is more likely to occur, which can be improved by releasing the left-turn vehicles before the through-right vehicles in the intersection signal scheme. The case study shows the proposed models have good performance, with the MAPE value of 20%.

A variable message sign (VMS), which is a key component of intelligent transportation systems, has been frequently used in the management of urban roads and motorways to provide drivers with real-time traffic condition information about a road section or area. Nevertheless, there is a lack of unified regulations for VMS design, which makes it difficult to accurately determine the understandability and legibility of VMS information. In practice, inappropriate designs of VMSs are common, such as overload of VMS information and excessive number of phases, particularly on the urban roads of China. Building on our earlier findings obtained by surveys, in this study, field tests were conducted to assess the reliability of VMS information in terms of the visual perception characteristics of drivers. For a full visual perception, the information displayed on a VMS must be reliable, i.e., it should be easy for drivers to detect, obtain, and understand the messages they require. Two basic theories-information theory and visual perception theory-were introduced to build a quantification model of VMS information, select evaluation indices, and design the experimental process. A total of 24 drivers participated in the field experiments and questionnaires. Five indices-information obtainment rate, periodic validity, driver subjective scoring and the corresponding UI (represents information intelligibility), and CE (represents information legibility)-were analyzed to evaluate their relationships to VMS information reliability. The results confirmed that the amount of information, and the scrolling period considering redundant distance, significantly affect the reliability of VMSs information. For static VMSs, the information obtainment rate and the subjective scoring decrease with increasing amount of information. The recollection accuracy of the drivers significantly declines when the amount of information shown increases to 90 bits, corresponding to an information obtainment rate of less than 0.8 and UI equal to 0. For dynamic VMSs, the information reliability deteriorates as the scrolling period shortens and the number of phases increases. Unreasonable reliability is found when the periodic validity is less than 0.9, i.e., the actual scrolling period is more than 10% less than the calculated one, corresponding to CE equal to 0. The reliability of information was evaluated by combining the subjective scoring of the drivers and a data-based statistical analysis and considering driving safety. Accordingly, it was recommended that 90 bit is the maximum amount of information to be shown on a VMS and that the preferred scrolling period of each phase of a dynamic VMS is 5 s. The results of this study support the objective of providing reliable information to drivers by addressing the problems related to the amount of information and presentation time for VMSs. These findings provide a basis for determining the thresholds for VMS information to promote practical and user-friendly designs of VMSs on urban roads.

Probabilistic yielding behavior is commonly observed at permitted left-turn signalized intersections in China. Nevertheless, its impact on traffic capacity has not been explored in existing research. The uniqueness of this traffic operation is that neither left-turn traffic nor through traffic holds an absolute priority. Based on queuing theory, this research developed an analytical capacity model that took into account the probabilistic priority phenomenon at permitted left-turn signals. To validate the developed capacity model, stochastic simulations with different combinations of left-turn traffic yielding rates and through-traffic flow rates were performed. It was found that modeling results from the analytical model precisely matched the stochastic simulation results. In comparison with traditional capacity estimation models that assumed through traffic holds an absolute priority, this research revealed that when through-traffic flow rate is around 1000 vehicles per hour (vph), the capacity of left-turn traffic increased from 233 vph to 536 vph when left-turn traffic yielding rates decrease from 1 to 0.2; whereas when left-turn traffic yielding rates decreased from 0.2 to 0, left-turn capacity increased sharply to 1200 vehicles per hour (vph). In this regard, it is critical to take into account the probabilistic left-turn yield behavior when developing permitted left-turn signal warrants.

Oversaturated signalized intersections have significant impacts on traffic signal coordinated control systems, especially in traffic flow efficiency. Therefore, it is critical to optimize the coordinated control methods of artery for oversaturated intersections. In this study, we first discuss the definitions of oversaturated, critical intersection, and direction registration. Next, a modified forward-backward procedure method is proposed based on maximum traffic flow with adjusting the signal timing parameters, such as cycle, green time, and offset. Finally, the proposed method is evaluated by the maximum number of throughputs, minimum average delay time, and minimum average stops. Compared to the initial timing control, the results indicated that the throughputs are increased by 12.72%, average delay time and stops are decreased by 28.55% and 14.97%.

An urban arterial weaving section has been considered a bottleneck in urban roadway systems, which is one of the key contributing factors to the occurrence of the capacity-drop phenomenon. This paper proposes a novel lane signal control method to regulate the weaving traffic flow at urban arterial weaving sections. With consideration of the operational characteristics of the weaving section and the imbalance of traffic at each entrance lane, a reduction coefficient of the weaving traffic was adopted. A capacity calculation model for weaving traffic under lane signal control was developed. The optimization model was established to derive the optimal lane signal control scheme. The objective function was to maximize the weaving section's capacity, and the constraints were the safe time headway between two adjacent phases. The proposed capacity estimation model was validated using field data collected at a representative urban arterial weaving section in Chongqing City, China; it was found that the mean absolute percent error was 4.7%. Modeling results demonstrate that the actual capacity of the weaving section significantly increased after adopting the lane signal control strategy. During the morning peak period, the actual capacity was 3,265pcph (passenger cars per hour), which improves by 28.14% under the optimal scheme of two-phase lane signal control. The weaving capacity improvement for the three-phase lane single control is found to be 3,458pcph, which improves by 35.71% under the three-phase control strategy. This paper used capacity reduction as index to test the robust of entrance lane, facing the increasing demand for traffic.

Roadside LiDAR deployment provides a solution to obtain the real-time high-resolution micro traffic data of unconnected road users for the connected-vehicle road network. Single roadside LiDAR sensor has a lot of limitations considering the scant coverage and the difficulty of handling object occlusion issue. Multiple roadside LiDAR sensors can provide a larger coverage and eliminate the object occlusion issue. To combine different LiDAR sensors, it is necessary to integrate the point clouds into the same coordinate system. The existing points registration methods serving mapping scans or autonomous sensing systems could not be directly used for roadside LiDAR sensors considering the different feature of point clouds and the spare points in the cost-effective roadside LiDAR sensors. This paper developed an approach for roadside LiDAR points registration. The developed points-aggregation-based partial iterative closest point algorithm (PA-PICP) is a semi-automatic points registration method, which contains two major parts: XY data registration and Z adjustment. A semi-automatic key point selection method was introduced. The partial iterative closest point was applied to minimize the difference between different LiDARs in the XY plane. The intersection of ground surface between different LiDARs was used for Z-axis adjustment. The performance of the developed procedure was evaluated with field-collected LiDAR data. The results showed the effectiveness and accuracy of data integration using PA-PICP was greatly improved compared with points registration using the traditional iterative closest point. The case studies also showed that the occlusion issue can be fixed after PA-PICP points registration.

Unsafe driver behavior has been a major concern for traffic safety. Limited studies were conducted for driver behavior analysis on ramp-related areas due to limited data. The advanced Intelligent Transportation Systems (ITS) technologies, such as connected-vehicles, are helpful to reduce driver behavior fault. However, considering the numerous ramps in the road network in the United States, priority of ITS deployment needs to be given to those sites with a high risk of having driver behavior fault. This paper analyzed the role of driver behavior fault in crashes/near-crashes on ramp-related areas with the Strategic Highway Research Program 2 Naturalistic Driving Study (NDS) data. A total of 428 crash/near-crash records and 100 baseline events (normal driving) were extracted from the database. It is found that driver behavior fault is the most important factor in the occurrence of crashes/near-crashes on ramp-related areas. Driver distraction is the most common types of driver behavior faults leading to crash/near-crash. The influence of different factors on driver behavior fault was also examined. Gender and Level of Service (LOS) were found highly related to unsafe driver behavior. Female drivers were more likely to have unsafe driver behavior at ramp-related areas. The LOS did not impact driver behavior significantly until the traffic was congested. It is recommended to initially deploy connected-vehicle devices at the sites with heavy traffic volume.

The contradictory relation between traffic demands and traffic networks is the source and motive force to promote urban traffic forward harmoniously.It can fully embody the integrated concept of land use and transportation from the integrated,balanced and harmonious configuration of the two.In this paper,based on the alterability of the traffic demands and traffic networks which is reflected by the traffic demand function and road traffic impedance function,a model of coupling relation between them is built with equilibrium principle and a method to make the city and traffic planning integrate is also proposed on the basis of the traffic demands and traffic networks double balanced coordination.Also a standard to judge the harmony level of the traffic demands and traffic networks is introduced.This method can integrate the traffic demands and traffic networks simultaneously and realize the bi-directional equalization between urban traffic flow and traffic demand volume.

For the bus has serious impact on the intersection running effective, the paper gives a new passenger car equivalent method for the bus according to the bus's time-space characteristics. When the bus arrives and departs the intersection without stopping, the passenger car equivalent is set as the section of highway, when the bus passes the intersection experiencing stop, the passenger car equivalent for the bus considering some factors, such as the bus's stop space between the stop line, the bus's starting-up characteristics and the bus's impact on the vehicle's behind it, then the bus's passenger car equivalent is given. Through the example using the simulation methods, the different passenger car equivalent of the bus is tested, and it is proved, the methods given in the paper can decrease the vehicle's delay at the signalized intersection.

By analyzing some slow traffic ways in some domestic and international cities, this paper proposes a combination mode of slow traffic ways which is suitable for Chongqing, a typical mountain city. The combination mode is composed of personal rapid transit system, Crossing-river cableway, pedestrian access and overhead pedestrian trails, which are corresponding to the pedestrian corridor, pedestrian street and pedestrian unit, with the consideration of interface between them. This model can solve the problem which bicycles are inappropriate for Chongqing people fundamentally, and make a high efficiency, low power consumption slow traffic patterns.

The application of waste tire rubber in highway engineering mainly focuses on the modification of asphalt rather than the asphalt mixture, which restricts the application of waste tire. The addition of rubber has an effect on the performance of the mixture because of the obvious difference between rubber and mineral aggregates. This paper makes a research on the preparation technology of the specimens made of crumb rubber modified asphalt mixture in the laboratory by means of the study of selection of rubber、aggregate gradation、compaction temperature and so on. The effect of compaction was investigated in terms of the air void of the specimens under different preparation conditions. The optimal preparation process of rubberized asphalt mixture is put forward which could be proved to effectively control the pavement damages such as loose、stripping and so on.

The operational safety and service quality of urban expressway are greatly affected by the distance of interchange opening. This paper definited the distance of 4 kinds of opening combination modes, showed the calculation models, and established a piecewise function model of opening distance, traffic volume and speed. It also proposed that, meeting the requirements of minimum distance, the opening distance should be determined with the consideration of actual road traffic conditions, by analyzing the relationship between the opening distance, traffic volume and speed. The results can be the references for the traffic management and the planning and designing of urban expressway interchange.

Optimization of urban public transit network is an important means to improve the efficiency of urban public transit system. This paper presents an optimization objective function of public transit network which is taking into account the optimal cost of administrator and transit user, and restrictions through analyzing the optimization goals and restricted conditions of urban public transit line network with the equilibrium theory. A further multiple objective optimization model of public transit network based on traffic equilibrium theory is established through considering related factors of public transit network. Finally, the algorithm of the proposed model is established according to the system decomposition principle.

目前,大力发展城市轨道交通已成为我国大、中城市交通发展的目标,而交通一体化规划的优劣将直接影响城市轨道交通在城市交通中作用的发挥。结合深圳市地铁1号线续建工程公共交通设计,分析交通一体化规划在城市轨道交通中的重要作用,以及如何做好交通一体化规划。