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Road traffic signs are part of the road infrastructure components meant to ensure the safe use of roads by motorists and pedestrians alike. A good knowledge and comprehension of road signs helps ensure smooth flow of traffic, improves safety for other motorists and provides drivers with good reaction time to comply with the message dictated by the signs. Abu Dhabi, being the capital of the UAE, brings together people from all over the world for work, business or tourism. Abu Dhabi has quality roads and traffic signage together with an efficient police force that enforces adherence to traffic rules. Despite all these and the reduced fatalities in absolute terms, traffic violations have been increasing exponentially, resulting in five million traffic fines in 2019 for a population of about 2.9 million inhabitants. This study sought to assess motorists' comprehension of the various traffic signs used across the UAE. The results of the survey (N = 200) revealed that the drivers were able to correctly identify 77% of the road signs in the survey. It was also found that the respondents failed to correctly identify traffic signs within the specific category referred to as "advance warning signs". Respondents' education, nationality, gender, and marital status did not have any statistically significant effects on the results compared to earlier studies. It is recommended that more attention be focused on driver education and training. [ABSTRACT FROM AUTHOR]

Abstract: This article proposes a novel methodology that uses the bi‐level programming formulation to calibrate the expected total demand and the corresponding demand variability of traffic networks. In the bi‐level formulation the upper‐level is either a new maximum likelihood estimation method or a least squares method and the lower‐level is the strategic user equilibrium assignment model (StrUE) which accounts for the day‐to‐day demand volatility. The maximum likelihood method proposed in this article has the ability to utilize information from day‐to‐day observed link flows to provide a unique estimation of the total demand distribution, whereas the least squares method is capable of capturing link flow variations. The lower‐level StrUE model can take the total demand distribution as input, and output a set of link flow distributions which can then be compared to the link‐level observations. The mathematical proof demonstrates the convexity of the model, and the sensitivity to the prediction error is analytically derived. Numerical analysis is conducted to illustrate the efficiency and sensitivity of the proposed model. Some possible future research is discussed in the conclusion. [ABSTRACT FROM AUTHOR]

Abstract: This article proposes an extension of the strategic user equilibrium proposed by Waller and colleagues and Dixit and colleagues. The proposed model relaxes the assumption of proportional Origin‐Destination (O‐D) demand, as it accounts for users’ strategic link choice under independently distributed O‐D demands. The convexity of the mathematical formulation is proved when each O‐D demand is assumed to follow a Poisson distribution independently; link flow distributions and users’ strategic link choice are also proved to be unique. Network performance measures are given analytically. A numerical analysis is conducted on the Sioux Falls network. A Monte Carlo method is used to simulate network performance measures, which are then compared to the results computed from the analytical expression. It is illustrated that the model is capable of accounting for demand volatility while maintaining computation efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The prediction of bus arrival time is important for passengers who want to determine their departure time and reduce anxiety at bus stops that lack timetables. The random forests based on the near neighbor (RFNN) method is proposed in this article to predict bus travel time, which has been calibrated and validated with real‐world data. A case study with two bus routes is conducted, and the proposed RFNN is compared with four methods: linear regression (LR), k‐nearest neighbors (KNN), support vector machine (SVM), and classic random forest (RF). The results indicate that the proposed model achieves high accuracy. That is, one bus route has the results of 13.65 mean absolute error (MAE), 6.90% mean absolute percentage error (MAPE), 26.37 root mean squared error (RMSE) and 13.77 (MAE), 7.58% (MAPE), 29.01 (RMSE), respectively. RFNN has a longer computation time of 44,301 seconds for a data set with 14,182 data. The proposed method can be optimized by the technology of parallel computing and can be applied to real‐time prediction. [ABSTRACT FROM AUTHOR]

Abstract: Connected vehicles are able to proactively change speed to adapt to the prevailing traffic condition. Even in the mixed traffic environment, connected vehicles may function as leading vehicles, hence influencing the driving pattern of following nonconnected vehicles. This article proposes a cell‐based simulation approach to model the proactive driving behavior of connected vehicles. First, a state variable of connected vehicles is introduced to track the trajectory of connected vehicles. Then the exit flow of cells containing connected vehicles is adjusted to simulate the proactive driving behavior, such that the traffic light is green when the connected vehicle arrives at the signalized intersection. The second part of the article conducts numerical tests to examine the effect of the proactive driving behavior of connected vehicles. Extensive test results consistently show that the presence of connected vehicles contributes significantly to the smoothing of traffic flow and vehicular emission reductions in the network. [ABSTRACT FROM AUTHOR]

The current method for the analysis of sight distance for left-turn vehicles at signalized intersections assumes that all component variables are deterministic. This paper presents a probabilistic approach based on such random variables as major-road speed, time gap required for left-turn vehicle, vehicle width, lateral position of left-turn vehicle, distance between driver eye of left-turn vehicle and its front, and lateral and longitudinal positions of positioned opposing left-turn vehicle. A safety margin is defined as the difference between available and required sight distances. Relationships for the mean and standard deviation of the safety margin were developed using the first-order second-moment (FOSM) method. This method identifies the offset (distance between left edge of the left-turn lane and right edge of the opposing left-turn lane) at signalized intersections for a desired probability of noncompliance based on intersection and traffic characteristics. The proposed reliability method was validated using Monte Carlo simulation, and design graphs were established. The results show that the deterministic method provides very conservative offsets and that the offset is most sensitive to vehicle width and lateral distance-related variables and less sensitive to longitudinal distance-related variables. [ABSTRACT FROM AUTHOR]

Smart traffic engineering and intelligent transportation services are in increasing demand from governmental authorities to optimize traffic performance and thus reduce energy costs, increase the drivers' safety and comfort, ensure traffic laws enforcement, and detect traffic violations. In this paper, we address this challenge, and we leverage the use of Artificial Intelligence (AI) and Unmanned Aerial Vehicles (UAVs) to develop an AI-integrated video analytics framework, called TAU (Traffic Analysis from UAVs), for automated traffic analytics and understanding. Unlike previous works on traffic video analytics, we propose an automated object detection and tracking pipeline from video processing to advanced traffic understanding using high-resolution UAV images. TAU combines six main contributions. First, it proposes a pre-processing algorithm to adapt the high-resolution UAV image as input to the object detector without lowering the resolution. This ensures an excellent detection accuracy from high-quality features, particularly the small size of detected objects from UAV images. Second, it introduces an algorithm for recalibrating the vehicle coordinates to ensure that vehicles are uniquely identified and tracked across the multiple crops of the same frame. Third, it presents a speed calculation algorithm based on accumulating information from successive frames. Fourth, TAU counts the number of vehicles per traffic zone based on the Ray Tracing algorithm. Fifth, TAU has a fully independent algorithm for crossroad arbitration based on the data gathered from the different zones surrounding it. Sixth, TAU introduces a set of algorithms for extracting twenty-four types of insights from the raw data collected. These insights facilitate the traffic understanding using curves, histograms, heatmaps, and animations. The present work presents a valuable added value for academic researchers and transportation engineers to automate the traffic video analytics process and extract useful insights to optimize traffic performance. TAU is a ready-to-use framework for any Transportation Engineer to better understand and manage daily road traffic (video demonstrations are provided here: https://youtu.be/wXJV0H7LviU and here: https://youtu.be/kGv0gmtVEbI). The source code is available at: https://github.com/bilel-bj/TAU. [ABSTRACT FROM AUTHOR]

The Aw-Rascle-Zhang (ARZ) model can be interpreted as a generalization of the Lighthill-Whitham-Richards (LWR) model, possessing a family of fundamental diagram curves, each of which represents a class of drivers with a different empty road velocity. A weakness of this approach is that different drivers possess vastly different densities at which traffic flow stagnates. This drawback can be overcome by modifying the pressure relation in the ARZ model, leading to the generalized Aw-Rascle-Zhang (GARZ) model. We present an approach to determine the parameter functions of the GARZ model from fundamental diagram measurement data. The predictive accuracy of the resulting data-fitted GARZ model is compared to other traffic models by means of a three-detector test setup, employing two types of data: vehicle trajectory data, and sensor data. This work also considers the extension of the ARZ and the GARZ models to models with a relaxation term, and conducts an investigation of the optimal relaxation time. [ABSTRACT FROM AUTHOR]

Cooperative vehicular ad-hoc networks are currently under development for improving traffic safety and efficiency. The strict requirements of traffic safety applications demand robust communication protocols that are able to efficiently operate under diverse and challenging operating conditions. In this context, this work proposes the joint study and evaluation of cooperative applications with potential dependencies, and evaluates a context-aware communications mechanism that exploits traffic context information to maximize the applications' effectiveness. The benefits of the proposed approach are illustrated with the intersection collision warning and emergency electronic brake lights applications. [ABSTRACT FROM AUTHOR]

This research aims at developing a system of real-time simulation-based dynamic traffic model under mixed traffic flow conditions. The system consists of two layers, namely, simulation layer and real-time control layer. The system is implemented based on rolling horizon approach, which is advanced for each stage; thus real-time data can be incorporated within the framework. In order to predict normative, as well as predictive, information, a simulation-based dynamic traffic assignment model is employed within each stage. Empirical data for a real city network, such as flows from vehicle detectors, are used to validate the model in a real-time environment. The values of mean absolute percentage error and root-mean-squared percentage error are within 15%, and the results show promising agreements between observed and simulated flows. [ABSTRACT FROM AUTHOR]

No track thermoplastic is a relatively new thermoplastic traffic marking material which can be installed on newly constructed asphalt pavement shortly after finishing paving operations. The main objectives of this study are (1) to develop a test procedure that can be used to determine whether a thermoplastic traffic marking is a no track thermoplastic traffic marking and (2) to run field tests to obtain performance data through real applications of industry-proclaimed no track thermoplastic traffic markings. Sixteen transverse lines were installed in the field for performance evaluation. The research team measured several parameters in the field such as appearance, retroreflectivity, and color. By comparing the testing parameters between no track and regular thermoplastic traffic markings, the research team intended to select a parameter that can be used to develop technical specifications to help decision makers define no track thermoplastic traffic markings. It was found that the best parameters that can be used to define a no track thermoplastic traffic marking were the CIELAB ΔE* value and the CIE94 color tolerance ΔE94*. These two parameters were proposed by the International Commission on Illumination and have been used extensively for measuring color differences. As compared to other testing parameters, the change of these two parameters with time is more consistent and the selected no track thermoplastic traffic markings produced significantly lower ΔE* and ΔE94* values as compared to the regular thermoplastic traffic marking. The research results have the potential to be used by decision makers to develop technical specifications to guide the real engineering applications of no track thermoplastic traffic markings. [ABSTRACT FROM AUTHOR]

This paper presents an extensive investigation regarding the impacts of green signal countdown devices (GSCD) on the intersection safety and efficiency, based on field observation of critical driver and vehicle related parameters at two similar intersections (one with GSCD and the other without GSCD) in Shanghai. Statistical analysis results have revealed that the installation of GSCD can (1) encourage drivers to pass the stop-line during the amber time with higher speeds and thus result in better utilization of the amber time and increased capacity of the intersection approach; (2) smooth the driver's response to the phase transition and effectively prevent the sudden change of speeds; (3) effectively eliminate the intersection dilemma zones by allowing the drivers to envision the phase transition and make decisions in advance; and (4) significantly reduce the number of red-light violations. Despite its effectiveness in facilitating the driver decision-making process, the installation of GSCD may adversely increase the possibility of collisions with unexpected crossing vehicles or pedestrians due to the significantly increased speeds of vehicles approaching the amber time. The analysis results from this study will offer the basis for traffic practitioners, researchers, and authorities in China to assess the impact of GSCD with respect to its operational and safety performance, and propose guidelines for its proper field installation. [ABSTRACT FROM AUTHOR]

Decisions regarding the location of motorway interchanges need to be made very carefully because of their economic and political implications. In this paper, we present three optimization models aimed at assisting road administrations when they deal with motorway interchange location problems. The decisions are assumed to be made from the perspective of road users, with the objective of minimizing travel costs. Two of the models are based on existing hub location models, whereas the third one is a new model. The usefulness of the models in real-world situations is illustrated with a case study involving A25, one of the most important Portuguese motorways. When applied to this case study, the new model performed in general clearly better than the other two. [ABSTRACT FROM AUTHOR]

An urban traffic network of signalised intersections can be suitably modelled as a discrete event system, in which the traffic light alternations are described by means of timed coloured Petri nets (TCPNs). A module of basic traffic TCPN model with a signal timing plan for a day is successfully constructed. The traffic operations are ruled by the control logic of TCPN and an analysis method using place invariant is verified. From the basic TCPN model, some of the complicated traffic signal models will be easily obtained. Moreover, a real-world supervisor of the urban traffic light system is implemented by the new methodology. Finally, an urban traffic light control system with five intersections is realised. Also, the performance of the supervisor of the urban traffic light system can be confirmed by the simulation results. [ABSTRACT FROM AUTHOR]

Abstract: We study the congestion on a homogeneous roadway with open boundaries. Three different phases are identified. Both numerical and analytical results are presented. For stationary boundaries, three different flow can be associated with a single density on the fundamental diagram. When the congestion is characterized by numerous jams, the system is homogeneous and the traffic flow is low. When the system is dominate by a single jam, the time trajectory traces out finite cycles and a higher traffic flow can be supported. If the cycles fill up a two-dimensional area, the traffic flow remains constant as the density changes; if the cycles collapse into a one-dimensional loop, a much higher traffic flow can be achieved. We also discuss the effects of dynamical boundaries. [Copyright &y& Elsevier]

This paper sets out the safety and traffic management arrangements for one of the most prestigious events in the sports calendar, the PGA World Golf Championship, held for the first time in the UK in 2006. Hertfordshire Highways was responsible for ensuring that safety was maintained and gridlock avoided during the six-day event. This paper describes the meticulous planning arrangements prior to the event, as well as the coordination between the many organisations responsible for ensuring that traffic could enter and exit the various car parks and that plans were in place in the event of an emergency on site. The paper ends with lessons learned and considers what actions taken might be different if an event of this scale were to be held in Hertfordshire in the future. [ABSTRACT FROM AUTHOR]

Abstract: The fuzzy version of group model of traffic flow in street networks is presented. At first definitions of vehicles groups and its elementary transformations are introduced. Then the generic transformer of vehicle groups at an entrance of intersection is derived and network evaluation performed. The introduction of the fuzzy group definition as fuzzy set of similar vehicle groups made possible to extend results have obtained for crisp model to fuzzy one. Vehicle group transformations were generalized to fuzzy environment by law of extension and new formulas for delay were derived. Remarks concerning delay defuzzyfication and advantages of fuzzy group model over crisp one ended the paper. [Copyright &y& Elsevier]

In July 2003 a new Road Code was approved by the Italian parliament. Among other changes, the law states that on three-lane motorways the right lane should not be reserved anymore to slow vehicles. The model developed in this paper casts doubts on the wisdom of such a change, suggesting that reserving a separate lane for slow vehicles is generally better, in terms of number of accidents and slow-downs, than treating all vehicles the same way. In addition, a value for the speed threshold below which vehicles are considered slow can be found, for which the old rule also performs better in terms of average speed. This conclusion has applications beyond the Italian case. Moreover, it is shown to be extremely robust to refinements of the main assumptions concerning driving attitudes and the stochastic arrival of accidents. [ABSTRACT FROM PUBLISHER]

The article offers information about the National Committee on Uniform Traffic Control Devices (NCUTCD). It discusses the history of the NCUTCD from the early establishment of the Manual on Uniform Traffic Control Devices (MUTCD), and its purpose of providing technical expertise and assistance on traffic controls, development of standards and warrants for traffic control devices. It notes that the NCUTCD's has technical committees that include Regulatory, Signals, and Markings.

This paper presents a theory of traffic equilibrium which involves responsive signal control policies; in this theory drivers' route choices and the control policy's choice of green times are treated in a symmetrical manner. The central theme of the paper is the iterative optimization assignment algorithm. This algorithm may be considered as a means of calculating equilibria which are consistent with a given responsive control policy. But it may also be regarded as a highly idealized model of the day to day dynamics of drivers' route choices when a responsive signal setting policy is employed; on "day" 1 the signals are held fixed and drivers settle down to an equilibrium flow pattern, on "day 2" the flow pattern is held fixed and the signals are updated according to the control policy for the fixed flow pattern, on "day" 3 the signals are held fixed and drivers settle down to an equilibrium flow pattern.... We state natural but strong conditions on the responsive control policy which guarantee that this algorithm is bound to converge to a convex set of (flow, control) pairs such that (i) the flow is a user equilibrium and (ii) the control parameters satisfy the responsive control policy; and we give a proof of convergence under these conditions--we do not seek to minimize total travel cost. Our conditions involve the delay or cost formula used; with the BPR cost formula, modified in a natural way to allow for green times, the traditional policy of choosing control parameters which minimize delay for the observed traffic pattern does satisfy these conditions in full. However, with Webster's delay formula traditional control policies are a long way... [ABSTRACT FROM AUTHOR]

The author presents his views about the third motor age, wherein the goal of maximizing traffic speed and volume is being balanced against other goals for creating livable settings. He mentions that local elected officials, specifically mayors, stated that the cost of providing even more capacity has been too high, financially and in terms of quality of life. As a traffic engineer, he presents his views about the dominant features of the current road system. Traffic engineers have defined and responded to the traffic problem with vertical thinking and attention has turned to efficient innovations like smart cars, intelligent vehicle highway systems, and better signal systems.

In this article, the author responds to criticisms received by his article on the history of roads and road traffic from Professor Wilson. The author deals with the criticisms which fall into six categories: his sketch of the historiography of the subject; his emphasis on traffic rather than road surfaces; the interpretation of the figures in tables; the reality of the published carrying schedules; the selection of some literary evidences against others; and his apparent confusion over stage-coaches. In so far as Wilson's authorities support his views, they do so only in showing that his use of them was somewhat incautious.

Urban road noise has always been an important environmental problem for man from ancient history. But despite the fact proven by measurements and calculations that road traffic is the main source of noise in urban areas, citizens have the tendency to accept the situation as part of modern way of life and as a "necessary evil". This paper compares the results of noise measurements and the noise related complaints of the citizens from Timisoara. [ABSTRACT FROM AUTHOR]

The article presents the author's experiences in his transportation engineering career. Topics include the introduction of the 1985 edition of the "Highway Capacity Manual," the mainframe version of TRANSYT 7F, and the evolution of the 1971 edition of "Manual on Uniform Traffic Control Devices" (MUTCD). It also mentions the principles on start-up delay and headway by Bruce Greenshields and the 1982 edition of "Traffic Engineering Handbook" by the Institute of Transportation Engineers.

In this paper, we introduce new models of non-homogenous weighted Koch networks on real traffic systems depending on the three scaling factors r1,r2,r3∈(0,1). Inspired by the definition of the average weighted shortest path (AWSP), we define the average weighted receiving time (AWRT). Assuming that the walker, at each step, starting from its current node, moves uniformly to any of its neighbors, we show that in large network, the AWRT grows as power-law function of the network order with the exponent, represented by θ(r1,r2,r3)=log4(1+r1+r2+r3). Moreover, the AWSP, in the infinite network order limit, only depends on the sum of scaling factors r1,r2,r3. [ABSTRACT FROM AUTHOR]

The article underscores a roadmap of highway safety legislation. It states that a report from US pressure group Advocate for Highway and Auto Safety underlines gaps in a list of 15 important and lifesaving highway safety laws. Relative to this, this necessitated that governors and state legislators in the United States should act correspondingly on this issue. It is also posed that motor vehicle crashes caused 42,000 and over 2.5 million injuries in 2006.