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Intersections are at the core of congestion in urban areas. After the end of the Second World War, the problem of intersection management has benefited from a growing body of advances to address the optimization of the traffic lights' phase splits, timing, and offset. These contributions have significantly improved traffic safety and efficiency in urban areas. However, with the growth of transportation demand and motorization, traffic lights show their limits. At the end of the 1990s, the perspective of autonomous and connected driving systems motivated researchers to introduce a paradigm shift for controlling intersections. This new paradigm is well known today as autonomous intersection management (AIM). It harnesses the self-organization ability of future vehicles to provide more accurate control approaches that use the smallest available time window to reach unprecedented traffic performances. This is achieved by optimizing two main points of the interaction of connected and autonomous vehicles at intersections: the motion control of vehicles and the schedule of their accesses. Considering the great potential of AIM and the complexity of the problem, the proposed approaches are very different, starting from various assumptions. With the increasing popularity of AIM, this paper provides readers with a comprehensive vision of noticeable advances toward enhancing traffic efficiency. It shows that it is possible to tailor vehicles' speed and schedule according to the traffic demand by using distributed particle swarm optimization. Moreover, it brings the most relevant contributions in the light of traffic engineering, where flow–speed diagrams are used to measure the impact of the proposed optimizations. Finally, this paper presents the current challenging issues to be addressed. [ABSTRACT FROM AUTHOR]

The optimization of intersection signal control can improve traffic efficiency, reduce congestion degree, and improve traffic safety. Aiming at implementing the coordinated adaptive traffic signal control (ATSC) across large-scale arterial network, multi-agent reinforcement learning (MARL) has been widely concerned and lucubrated. Nevertheless, the existing MARL-based ATSC studies suffers from several limitations: (1) While most existing researches focused on the mobility performance of controlled corridor, there calls for a methodology that aims at combine multi-objective performance on traffic safety, efficiency, and network coordination simultaneously; (2) Most methods ignore the correlations between multiple agents, nor considers the spatial–temporal dependencies among the corelated neighboring intersections due to high communications requirements, which can hardly be achieved in real adaptive coordination control. To overcome the aforementioned difficulties, a multi-objective reinforcement learning model (NACRL) for network-wide coordinated signal control is proposed. Firstly, to enforce a coordinated network control with safety and efficiency considerations, a reward mechanism inspecting both traffic safety and traffic efficiency indicators was designed to achieve ideal performance in terms of mobility, safety and smooth. Secondly, the proposed NACRL conducted a centralized training-decentralized execution framework, this overcomes the critical limitation of data transmission in the field implementation while explicitly analyzing the traffic state over the entire network instead of examining each isolated intersection. Last but not least, the proposed algorithm utilized the attention mechanism to dynamically capture the sophisticated spatial–temporal dependencies over the complex arterial network, which aids the better coordinated control over multi-agents deployed at the intersections across the corridor. To testify the effeteness of the proposed algorithm, extensive experiments were implemented in both large-scale synthetic traffic grid and real-world arterial network. The experiment demonstrated that the proposed NACRL algorithm outperforms other state-of-the-art baselines with simultaneously improved performance in terms of traffic safety, traffic efficiency and network coordination, as well as improved algorithm convergence and interpretability. [ABSTRACT FROM AUTHOR]

The intersection of a public road with a railway line in one level, called a rail-road crossing, is a particularly dangerous place due to the traffic flows crossing it. The regulations give absolute priority to a rail vehicle over a public road user; in addition, significant differences in the masses and speeds of moving vehicles require traffic regulation consisting of adequate passage protection. To this end, the road on which motor vehicles is equipped with road signs informing drivers that they are approaching an intersection with a railway line. The rail-road crossing, depending on the category, is equipped with signaling devices warning of an oncoming train and barriers closing the entire width of the road or part of it, operated or operating automatically. In Poland, the category of rail-road crossing, the associated method and type of security used at the crossing, is determined on the basis of relevant acts and internal regulations of the railway line manager. The paper presents an overview of the state of safety at rail-road crossings in Poland in the years 2008-2018, presents applicable regulations regarding traffic safety at rail-road crossings, and presents methods of protection of rail-road crossings. In addition, a map of concentration of events on rail-road crossings was presented for the area of the Silesian Voivodeship. The effect of the case study for the Silesian Voivodeship is to identify sensitive rail-road crossings with the highest number of events during the analysis period. [ABSTRACT FROM AUTHOR]

Urban road networks may benefit from left turn prohibition at signalized intersections regarding capacity, for particular traffic demand patterns. The objective of this paper is to propose a method for minimizing the total travel time by prohibiting left turns at intersections. With the flows obtained from the stochastic user equilibrium model, we were able to derive the stage generation, stage sequence, cycle length, and the green durations using a stage-based method which can handle the case that stages are sharing movements. The final output is a list of the prohibited left turns in the network and a new signal timing plan for every intersection. The optimal list of prohibited left turns was found using a genetic algorithm, and a combination of several algorithms was employed for the signal timing plan. The results show that left turn prohibition may lead to travel time reduction. Therefore, when designing a signal timing plan, left turn prohibition should be considered on a par with other left turn treatment options. [ABSTRACT FROM AUTHOR]

• Proposed a semi-actuated control logic for superstreet intersection. • The model uses a fuzzy-logic type 2 system and derives control parameters. • A VISSIM simulation estimates the quality of the proposed control algorithm. • The model is tested on a field superstreet under various traffic demand patterns. The paper presents a novel approach to RCUT control, based on the interval Type-2 fuzzy system (IT2FS). RCUT design, among other various alternative intersections, proposes dislocation of left and through movements from the main intersection for an increase in safety and efficient traffic conditions. This concept assumes the rise of two new U-turn intersections downstream from the main intersection that can be controlled by traffic lights. RCUT design is justified when U-turn traffic demands, along with demands from and to minor streets, are significantly lower than arterial street ones. The semi-actuated traffic control seems the most appropriate control mode that should be applied at the RCUT. Evaluation of semi-actuated traffic control based on IT2FS is compared with other traffic control modes. The results show that semi-actuated traffic control, based on IT2FS, can generate statistically better results than other well-known controls. [ABSTRACT FROM AUTHOR]

Stop signs are the primary form of traffic control in the United States. However, they have a tendency to be much less effective than other forms of traffic control like traffic lights. This is due to their smaller size, lack of lighting, and the fact that they may become visually obscured from the road. In this paper, we offer a solution to this problem in the form of a mobile application implemented in the Android platform: Stop Watcher. It is designed to alert a driver when they are approaching a stop sign using a voice notification system (VNS). A field test was performed in a snowy environment. The test results demonstrate that the application can detect all of the stop signs correctly, even when some of them were obstructed by the snow, which in turn greatly improves the user awareness of stop signs. [ABSTRACT FROM AUTHOR]

This study examined how objective measures of the local road environment related to safety were associated with change in physical activity (including active transport) among youth. Few longitudinal studies have examined the impact of the road environment on physical activity among children/adolescents in their neighborhoods. Participants were children aged 8–9 years ( n = 170) and adolescents aged 13–15 years ( n = 276) in 2004. Data were collected in 2004 and 2006 during follow-up of participants recruited initially in 2001 from 19 primary schools in Melbourne, Australia. Walking/cycling to local destinations was parent-reported for children and self-reported by adolescents. Moderate-to-vigorous physical activity (MVPA) during nonschool hours was recorded using accelerometers. Road environment features in each participant’s neighborhood (area within 800 m radius of their home) were measured objectively using a Geographical Information System. Linear regression analyses examined associations between road features and changes in active transport (AT) and MVPA over 2 years. Children’s AT increased but MVPA levels decreased in both age groups; on average, younger girls recorded the greatest declines. The number of traffic/pedestrian lights was associated with ΔAT among younger girls (B=0.45, p=0.004). The total length of walking tracks (in meters) was associated with ∆AT among younger girls ( B = 0.0016, p = 0.015) and adolescent girls ( B = 0.0016, p = 0.002). For adolescent boys, intersection density was associated with ∆AT ( B = 0.03, p = 0.030). Slow points were associated with ∆MVPA among younger boys before school ( B = 1.55, p = 0.021), while speed humps were associated with ∆MVPA among adolescent boys after school ( B = 0.23, p = 0.015). There were many associations for adolescent girls: for example, the total length of local roads ( B = 0.49, p = 0.005), intersection density ( B = 0.05, p = 0.036), and number of speed humps ( B = 0.33, p = 0.020) were associated with ∆MVPA during nonschool hours. Safety-related aspects of the built environment are conducive to physical activity among youth and may help stem age-related declines in physical activity. Passive road safety interventions may promote AT and physical activity among less active girls, in particular. [ABSTRACT FROM AUTHOR]

Driver performance in responding to the green-amber-red signal change was studied based on a sample of 2316 last crossing and first stopping vehicles collected by unobtrusive observations at 10 junction approaches in Singapore. Two schemes, a speed-distance diagram (S-D) and an acceleration-deceleration (A-D) diagram, were used to demarcate the driving situations; the driver actions, as revealed outcomes of driver decision-making, were mapped onto these diagrams. The speed-distance diagram can give some indication on what a driver would possibly do. The more complicated acceleration-deceleration diagram is useful for diagnosing the appropriateness of the driver actions. An application of the A-D diagram was demonstrated, and several situations prone to red-running were noted. [ABSTRACT FROM AUTHOR]

The goal of this study was to determine if traffic signals that are synchronized along a route are associated with fewer red-light violations than traffic signals that are not synchronized. A total 3600 cycles of traffic signals at 12 intersections along 2 major urban arteries were observed. Synchronized intersections were effective in reducing the likelihood of red-light running (RLR) by (a) providing fewer opportunities than nonsynchronized intersections for RLR and (b) having a lower rate of RLR relative to the number of opportunities. After adjustment for the number of opportunities, the odds of entering the intersections in red in synchronized intersections were nearly 1/7 the odds of RLR in nonsynchronized intersections. Congestion reduced the effectiveness of synchronized intersections relative to nonsynchronized intersections. Male drivers were slightly more likely to run red lights than female drivers, and the effects of synchronization were fairly constant across age, gender, and the presence or absence of passengers. Actual or potential applications of this research involve signal synchronization to reduce aggressive driving in general and RLR in particular. [ABSTRACT FROM AUTHOR]

Traffic signs are an integral part of the traffic control plan and they provide road users with necessary information on the upcoming situation. This paper aims to examine the level of understanding of traffic sign imagery used in different countries and to track participants' eye movement when they encounter unfamiliar signs. Tobii eye tracking glasses were used to track gaze differences between familiar and unfamiliar traffic signs. Our findings show that sign characteristics (such as the amount of information on the sign) and the observer's knowledge of the sign meaning have a significant impact on eye behaviour. Signs containing more information (loaded with more content) and unfamiliar to the participant systematically produced the longest overall and average fixations and gazing duration. Given that longer gaze time for unfamiliar traffic signs presents a potential traffic hazard, we evaluated the need for standardization of traffic signs. [ABSTRACT FROM AUTHOR]