Search

In this paper, we focus on trajectories at intersections regulated by various regulation types such as traffic lights, priority/yield signs, and right-of-way rules. We test some methods to detect and recognize movement patterns from GPS trajectories, in terms of their geometrical and spatio-temporal components. In particular, we first find out the main paths that vehicles follow at such locations. We then investigate the way that vehicles follow these geometric paths (how do they move along them). For these scopes, machine learning methods are used and the performance of some known methods for trajectory similarity measurement (DTW, Hausdorff, and Fréchet distance) and clustering (Affinity propagation and Agglomerative clustering) are compared based on clustering accuracy. Afterward, the movement behavior observed at six different intersections is analyzed by identifying certain movement patterns in the speed- and time-profiles of trajectories. We show that depending on the regulation type, different movement patterns are observed at intersections. This finding can be useful for intersection categorization according to traffic regulations. The practicality of automatically identifying traffic rules from GPS tracks is the enrichment of modern maps with additional navigation-related information (traffic signs, traffic lights, etc.). [ABSTRACT FROM AUTHOR]

We study a future Internet networking paradigm where instead of congestion control an open loop traffic control is applied. We aim to give theoretical foundations for data transfer controlled only by the access points of the network. The key characteristics of networks without congestion control are stability and efficiency addressed in this paper. We consider the queue length processes of data-flows on directed graphs. The stability is characterized by the ergodicity of these processes and the efficiency of the network is measured by the Price of Anarchy. Under restrictions on the input traffic rates we derive an achievable efficiency limit in a stable network for very general conditions, namely, for any network topology and for any buffer management policy. Moreover, we show that even for cyclic networks, which usually cause severe instability in networks, an upper bound for the loss of efficiency can be given independently of the size of the network under a fair AQM buffer management policy. Furthermore, for monotonic networks we present a reasonable choice for setting access capacities. Our results demonstrate that with a proper setting of access capacities of incoming flows the congestion collapse of the Internet can be avoided even without congestion control. [ABSTRACT FROM AUTHOR]

Large numbers of traffic accidents were experienced on the road networks of Arab Gulf Countries including United Arab Emirates (UAE). This had resulted in enormous loss of lives and economy. This article through using Abu Dhabi city, UAE capital as a case study is aiming to understand the reasons behind such safety problem through analysing a large accidents data-set extending over the period from 2008 to 2013. The traffic accidents data-set was obtained from Abu Dhabi traffic police department records and covers wide range of accident's attributes. A wide spectrum of accident attributes was analysed in the paper including but not limited to the time of accident, accident location, type of accident, reasons behind the accident, driver characteristics, road conditions, and many other accident attributes. A specific reasoning for each of these attributes was given by authors. Furthermore, recommendations to enhance the safety levels were introduced. [ABSTRACT FROM AUTHOR]

This study aim to determine the proportion of traffic rule infractions in Cali, Colombia, in places where a road traffic injury (RTI) occurred. Description of videotaping of sites where a person was injured in an RTI in 2009. Counts of road users and infractions were established for each road user group and were compared using a Z-test. They were found 13,491 users, distributed as follow: 8.9% were pedestrians, 4.6% cyclists, 24.6% motorcyclists, and 61.8% were automobile drivers. The most frequent traffic violation among motorcyclists was transiting on lines designated for other vehicles (55.2%). Among cyclists, the most frequent violations were transiting without a helmet (99.2%) and not wearing the designated vest (100%). Among pedestrians, crossing streets at prohibited places (77.3%), even at sites where a pedestrian bridge was present (72.7%), represented two common violations. Vulnerable road users committed more traffic infractions than automobile drivers (p < 0.001). High rates of traffic rule infractions among vulnerable road users were observed. Studies to better understand the occurrence of these behaviours and the promotion of effective interventions are warranted. [ABSTRACT FROM AUTHOR]

Urban traffic emissions have been increasing in recent years. To reverse that trend, restrictive traffic measures can be implemented to complement national policies. We have proposed a methodology to assess the impact of three restrictive traffic measures in an urban arterial by using a microsimulation model of traffic and emissions integrated platform. The analysis is extended to some alternative roads and to the overall network area. Traffic restriction measures provided average reductions of 45%, 47%, 35%, and 47% for CO2, CO, NOX, and HC, respectively, due to traffic being diverted to other roads. Nevertheless, increases of 91%, 99%, 55%, and 121% in CO2, CO, NOX, and HC, respectively, can be expected on alternative roads. [ABSTRACT FROM PUBLISHER]

Objective:The main goal of this research is to identify variables related to the expected time to death due to road traffic accidents (RTAs). Such research is expected to be useful in improving safety laws and regulations and developing new safety systems. The resulting information is crucial not only for reducing accident fatalities but for assessing related insurance policies. Methods:In this article, we analyze factors that are potentially associated with variation in the expected survival time after a road traffic accident using Weibull regression. In particular, we consider the association with alcohol involvement, deltaV, and restraint systems. Results:Our empirical results, obtained based on the NASS-CDS, indicate that the expected survival time for non-alcohol-impaired drivers is 3.23 times longer at a deltaVof 50 km/h than that for alcohol-impaired drivers under the same conditions. In addition, it was observed that, even when occupants were alcohol-impaired, if they were protected by both air bags and seat belts, their expected survival time after an RTA increased 2.59-fold compared to alcohol-impaired drivers who used only seat belts. Conclusion:Our findings may be useful in improving road traffic safety and insurance policies by offering insights into the factors that reduce fatalities. [ABSTRACT FROM PUBLISHER]

Average speed and speed variance are two characteristics of traffic flow that affect accident rates and severity near work zones. Operationally, work zones account for approximately 24% of the non-recurring delay. A policy for work zone speed limits has to delicately balance the safety and the efficiency impacts. If speeds are set too low, then avoidable congestion and speed violations might result. If speeds are set too high then, again, safety may be compromised. In this paper, results from field studies conducted on three Interstate 70 maintenance short-term work zones in rural Missouri are presented for three different speed limit scenarios: no posted speed limit reduction, 10 mph posted speed limit reduction, and 20 mph posted speed limit reduction. The 85th percentile speeds and standard deviation of speed were found to be 81 and 10 mph; 62 and 8 mph; and 48 and 6 mph, respectively for the three scenarios. The differences in 85th percentile speed and standard deviation of speed among all three scenarios were statistically significant. The per cent of drivers who exceed speed limit by over 10 mph were 15·4, 4·8, and 0·9%, respectively. Thus a reduction in posted speed limit was effective in reducing prevailing speeds and speed variances in short-term work zones in rural Missouri. [ABSTRACT FROM AUTHOR]

The aim of this paper is to examine Sweden's Vision Zero road safety policy. In particular, the paper focuses on how safety issues were framed, which decisions were made, and what are the distinctive features of Vision Zero. The analysis reveals that the decision by the Swedish Parliament to adopt Vision Zero as Sweden's road safety policy was a radical innovation. The policy is different in kind from traditional traffic safety policy with regard to problem formulation, its view on responsibility, its requirements for the safety of road users, and the ultimate objective of road safety work. The paper briefly examines the implications of these findings for national and global road safety efforts that aspire to achieving innovative road safety policies in line with the Decade of Action for Road Safety 2011–2020, declared by the United Nations General Assembly in March 2010. [ABSTRACT FROM AUTHOR]

Adaptive cruise control (ACC) can potentially improve quality-of-service and safety and reduce the environmental effect of the road traffic system. This article uses vehicle trajectories from traffic simulation to study effects of ACC on vehicle acceleration and deceleration rates. The analysis is based on traffic simulations with car-following models including ACC functionality and driver behavior in ACC-equipped as well as standard nonequipped vehicles. The simulation results show that ACC can improve the traffic situation in terms of reduced acceleration and deceleration rates even though macroscopic traffic properties may remain uninfluenced. This supports the hypothesized positive road safety and environmental effects of ACC. It is also established that the results are largely dependent on the assumptions made regarding driver behavior in ACC-equipped and standard vehicles. It is consequently crucial to include appropriate assumptions regarding driver behavior in traffic simulation–based analyses of ACC. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing interest in externalities in our society, mainly in the context of climate and air quality, which are of importance when policy decisions are made. For the assessment of externalities in transport, often the output of static traffic assignment models is used in combination with so-called effect models. Due to the rapidly increasing possibilities of using dynamic traffic assignment (DTA) models for large-scale transportation networks and the application of traffic measures, already several models have been developed to assess the externalities using DTA models more precisely. Different research projects have shown that there is a proven relation between the traffic dynamics and externalities, such as emissions of pollutants and traffic safety. This means that the assessment of external effects can be improved by using temporal information about flow, speed and density, which is the output of DTA models. In this paper, the modelling of traffic safety, emissions and noise in conjunction with DTA models is reviewed based on an extensive literature survey. This review shows that there are still gaps in knowledge in assessing traffic safety, much research is available concerning emissions, and although little research has been conducted concerning the assessment of noise using DTA models, the methods available can be used to assess the effects. Most research so far has focused on the use of microscopic models, while mesoscopic or macroscopic models may have a high potential for improving the assessment of these effects for larger networks. [ABSTRACT FROM AUTHOR]

Given the dynamic character of public transportation systems, it is difficult to respect accurately theoretical timetables. In real conditions, many disturbances may occur in transportation networks and cause troubles in vehicle schedules. In order to keep transportation systems as stable as possible, a real-time traffic regulation has to be performed by optimizing some regulation criteria that represent exploitation objectives. In this article, we deal with the regulation problem as a multi-criteria optimization one for which we propose a nonaggregative approach based on multi-agent systems. For a given disturbance, the approach firstly ensures an anytime generation of Pareto solutions set by using a distributed Tabu search. Then, the best compromise solution is determined through a multi-criteria evaluation process. Therefore, two multi-criteria evaluation procedures are also suggested: Plurality voting procedure and fuzzy-based procedure. In order to assess the distributed approach, an experimental study was performed on the base of real scenarios. [ABSTRACT FROM AUTHOR]

The situation awareness (SA) of air traffic controller (ATCO) students, including the temporal aspect of SA, was measured by means of their visual information acquisition during simulator training. The measurements were defined both at an individual level and at a team level. SA and team SA (TSA) were measured by means of eye-movement data: first, the extent to which individual ATCOs focused or distributed their visual attention in the interface; second, the extent to which ATCO teams were actively involved in planning tasks. Planning was measured based on how ATCO teams attended to tactical and strategic monitoring tasks. This enabled process-oriented measurements of SA and TSA that predicted aspects of performance and were sensitive to situational changes. [ABSTRACT FROM AUTHOR]

The current paper deals with the real-time regulation of an urban collective transport disrupted network, which is a very difficult problem, especially in the case of simultaneous disturbances (breakdowns, strikes, demonstrations, etc.). Indeed, regulators or decision makers have to carry out difficult tasks, which involves the assistance of a decision support system (DSS). The current paper presents the main part of this DSS, i.e. a regulation strategy generator and evaluator. Thus, a new hybrid approach is proposed using a fuzzy logic and evolutionary algorithm. It treats the regulation problem as an optimization one and provides the regulator with classified effective decisions by taking into account his/her preferences. [ABSTRACT FROM AUTHOR]

We describe the development of fast heuristics and methodologies for congestion minimization problems in directional wireless networks, and we compare their performance with optimal solutions. The focus is on the network layer topology control problem (NLTCP) defined by selecting an optimal ring topology as well as the flows on it. Solutions to NLTCP need to be computed in near realtime due to changing weather and other transient conditions and which generally preclude traditional optimization strategies. Using a mixed-integer linear programming formulation, we present both new constraints for this problem and fast heuristics to solve it. The new constraints are used to increase the lower bound from the linear programming relaxation and hence speed up the solution of the optimization problem by branch and bound. The upper and lower bounds for the optimal objective function to the mixed integer problem then serve to evaluate new node-swapping heuristics which we also present. Through a series of tests on different sized networks with different traffic demands, we show that our new heuristics achieve within about 0.5% of the optimal value within seconds. [ABSTRACT FROM AUTHOR]

In an attempt to uncover the personal and situational determinants of law violation, rates of prohibited right turns on red lights were observed at four intersections in Lubbock, Texas, for 726 male and female Anglo drivers. Drivers were either alone, or behind a violating model, or alone in the presence of a uniformed authority figure standing at the corner, or in the presence of both violating model and a uniformed authority figure. The uniform significantly decreased overall rates of violation. When no lawbreaking model was present, the effect was significant, but the introduction of a violating model cancelled the uniform's effect, and the corrupting effect of the model was more powerful in the Uniform condition than in the No Uniform condition. Generally, males and drivers under 30 were more likely to turn than females and drivers over 30. Females and older drivers were more hesitant to turn in the presence of a uniformed authority figure than were males and younger drivers, and females were particularly susceptible to the effects of a violating model's defiance of authority. [ABSTRACT FROM AUTHOR]