Real Intersection Research Articles

Performance Assessment Study of Road User Sensing Method by RSSI Combinations at Real Intersections

The authors have proposed a dedicated onboard “sensor” system utilizing wireless communication devices for surveillance of road users in terms of collision avoidance. The authors' “sensor” system estimates the positions of transmitters on road users by comparing the strengths of communications signals of ZigBee devices. According to the authors' experimental results, their system has competitiveness to the system utilizes time difference of arrival (TDOA) localization such as global navigation satellite systems (GNSS), at the point of robustness against multipaths in urban canyon. Moreover, their system thought to be capable of detecting road users in non line-of-sight area whom the vision sensors cannot observe. Therefore the system is promising as a composition element of a sensor fusion system for road safety, is the final target. In this work, the authors report about field operational experiments at real intersections. In experiments at real intersections, the authors tested the localization ability of their system and GNSS. The proposed system successfully detected the near pedestrians.

Validation of the Surrogate Safety Assessment Model for Assessment of Intersection Safety

The surrogate safety assessment model (SSAM) is a software application that reads trajectory files generated by microscopic simulation programs and calculates surrogate measures of safety. This approach eliminates the subjectivity associated with the conventional conflict analysis technique and allows assessment of the safety of a facility under a controlled environment before accidents occur. The specific goal of this research was to validate SSAM as a tool for accident prediction at urban intersections. Two methods were used for validation. The first method compared the simulated number of conflicts from the use of SSAM and the predicted number of injury accidents from analytic models in three reference intersection layouts (four-leg priority intersection, four-leg staggered intersection, and single-lane roundabout). The second method compared SSAM results with conflicts observed on site in four real intersections: two priority ones and two roundabouts. The results indicate that, despite some limitations related to the nature of current traffic microsimulation models, SSAM analysis is an extremely promising approach to assessing the safety of new facilities or innovative layouts.

Robust Optimization of Intersection Capacity

The optimal design of traffic light settings assumes in general that all the input parameters are known and constant for each design reference period, neglecting the effects of the uncertainty of the incoming flows or of other intersection characteristics, such as the saturation flows or the lost time. Responsive traffic plans only partially solve this problem, since they cannot vary continuously the traffic light settings, and generally consider only the input flow variations. The aim of this paper is to reformulate three well-known models for intersection capacity optimization in terms of stochastic programming and discuss their application to traffic light design of a real world intersection in Genoa.

Evaluation of Air Pollution Impacts of a Signal Control to Roundabout Conversion Using Microsimulation

Traditionally, the comparison between alternative types of road intersection control has focused on efficiency and safety. In recent years, the increasing importance of air pollution produced by vehicular traffic has suggested that environmental considerations should be added to the above aspects as a criterion for intersection design. Situations in which a conversion of traffic control type (e.g. signal to roundabout) is applied to an existing intersection are frequent in real networks, and it is interesting to evaluate how pollutant emissions may change as a result. The increasing availability of microsimulation software and emission models makes it now possible to conduct such detailed analyses at an operational level. The research described in this paper focused on a comparison of a roundabout and a signal-controlled intersection in terms of environmental performance. A real road intersection where a roundabout has replaced a fixed-time traffic signal has been analyzed. S-Paramics® software was used to extract detailed vehicle data required as inputs for instantaneous emission models. Microsimulation model parameters were calibrated for obtaining reliable outputs in terms of traffic pollutant emissions. Emissions of NOx, PM10 and total carbon were considered. It was found that the roundabout, generally, outperformed the fixed-time traffic signal in terms of vehicle emissions, although the difference between the two types of control was smaller in terms of environmental impacts than in terms of operational traffic performance.

Linear Determination of a Camera's Intrinsic Parameters Using Two Intersecting Circles

An approach using two intersecting circles is proposed as a linear approach for determining a camera's intrinsic parameters. The two intersecting coplanar circles have four intersection points in the projective plane: two real points and two circular points. In the image plane, the diagonal triangle - on which the image of the four intersection points composes a complete quadrangle - is a self-polar triangle for the projection curves of the circles. The vertex of the self-polar triangle is the null space of the degenerate conic formed by the image of the four intersection points. By solving the three vertices of the self-polar triangle using the image coordinates of the two real intersection points, the degenerate conic can be obtained. The image of the two circular points is then computed from the intersection points of the degenerate conic. Using the image of the circular points from the three images of the same planar pattern with different directions, the intrinsic parameters can be linearly determined.

Point searching in real singularcomplete intersection varieties: algorithms of intrinsic complexity

LetX1, . . . , Xn be indeterminates over Q and letX := (X1, . . . , Xn). Let F1, . . . , Fp be a regular sequence of polynomials in Q[X] of degree at most d such that for each 1 ≤ k ≤ p the ideal (F1, . . . , Fk) is radical. Suppose that the variables X1, . . . , Xn are in generic position with respect to F1, . . . , Fp. Further suppose that the polynomials are given by an essentially division-free circuit β in Q[X] of size L and non-scalar depth `. We present a family of algorithms Πi and invariants δi of F1, . . . , Fp, 1 ≤ i ≤ n− p, such that Πi produces on input β a smooth algebraic sample point for each connected component of {x ∈ Rn | F1(x) = · · · = Fp(x) = 0} where the Jacobian of F1 = 0, . . . , Fp = 0 has generically rank p. The sequential complexity of Πi is of order L(nd)O(1)(min{(nd)c n, δi})2 and its non-scalar parallel complexity is of order O(n(`+ lognd) log δi). Here c > 0 is a suitable universal constant. Thus, the complexity of Πi meets the already known worst case bounds. The particular feature of Πi is its pseudo-polynomial and intrinsic complexity character and this entails the best runtime behavior one can hope for. The algorithm Πi works in the non-uniform deterministic as well as in the uniform probabilistic complexity model. We exhibit also a worst case estimate of order (nn d)O(n) for the invariant δi. The reader may notice that this bound overestimates the extrinsic complexity of Πi, which is bounded by (nd)O(n).

Modeling and controlling an isolated urban intersection based on cooperative vehicles

In this paper, we propose a new approach for controlling the traffic at isolated intersections. We assume that all vehicles are equipped with on-board units (ITS station) that make them able to wirelessly negotiate the “right of way” according to the measurements done by the positioning system during their travel. A vehicle is allowed to cross the intersection if the green color is displayed to the driver in an on-board screen. The control aims to smooth the traffic through the sequence of vehicles authorized to traverse the intersection. The main challenge raised with the assumption is that the sequence must be dynamically formed by a real time application. The dynamic behavior of the traffic is considered discrete, in order to determine the switching rule according to the instantly observed events. We propose a model based on Timed Petri Nets with Multipliers (TPNM) which allows us to propose the control policy through the structural analysis. The resulting switching rules are very simplistic and efficient for isolated intersections. Indeed, microscopic simulations show that they perform as well as the optimal sequence based on the detection of vehicles at the entrance of the intersection. Moreover, the proposed approach has been tested through a real intersection.

Stationary Detection of the Pedestrian?s Intention at Intersections

This paper focuses on stat ionary detect ion of the pedestrian's intention to enter the traffic lane at intersections. We use an Interacting Multiple Model Extended Kalman Filter (IMM-EKF) based tracking approach as basic method to recognize this. In addition, we propose a novel Motion Contour image based HOG-like descriptor (MCHOG) in combination with Support Vector Machine (SVM) classification that reaches the decision at an accuracy of 99 % within the initial step at the curb of smart infrastructure. MCHOG implicitly comprises the body language of gait initiation, especially the body bending and the spread of legs. As a result of a case study at laboratory conditions we present Receiver Operating Characteristic (ROC) performance data and an evaluation of the span of time necessary for recognition. While MCHOG in special cases indicates detection of the intention before the whole body moves, on average it allows for detection of gait initiation within 6 frames at a frame rate of 50 Hz and an accuracy of 80%. In addition to a comprehensive evaluation under laboratory conditions we demonstrate feasibility of the methods in a real world intersection scenario and we show the gain which we achieve with MCHOG compared to the IMM-EKF approach.

Detection and Tracking of Moving Objects at Intersections Using a Network of Laser Scanners

In our previous work, we reported a system that monitors an intersection using a network of horizontal laser scanners. This paper focuses on an algorithm for moving-object detection and tracking, given a sequence of distributed laser scan data of an intersection. The goal is to detect each moving object that enters the intersection; estimate state parameters such as size; and track its location, speed, and direction while it passes through the intersection. This work is unique, to the best of the authors' knowledge, in that the data is novel, which provides new possibilities but with great challenges; the algorithm is the first proposal that uses such data in detecting and tracking all moving objects that pass through a large crowded intersection with focus on achieving robustness to partial observations, some of which result from occlusions, and on performing correct data associations in crowded situations. Promising results are demonstrated using experimental data from real intersections, whereby, for 1063 objects moving through an intersection over 20 min, 988 are perfectly tracked from entrance to exit with an excellent tracking ratio of 92.9%. System advantages, limitations, and future work are discussed.

Research of Signalized Intersection Delay Model by Using Optimization Method

By using optimization method, this paper has set up vehicle delay models of signalized intersection which based on vehicle average delay minimum, each phase remain time equal and each phase remain time balance. By using a real intersection’s geometry and traffic flow data, this paper has also set up the phase time with the above models, studied the results and evaluated these models

The Color of Change in Continental Feminist Philosophy

journal of speculative philosophy, vol. 26, no. 2, 2012 Copyright © 2012 The Pennsylvania State University, University Park, PA The Society for Phenomenology and Existential Philosophy (SPEP) was the first philosophy conference I attended along with my graduate peers. I gave thanks to the universe that at least everyone dressed better than what I had seen at the American Philosophical Association (APA) as a terrified undergraduate guest during a hire—and that the maleness of the philosophical milieu called the APA would recede for a few days. As silly as these two factors may sound in engendering an increased comfort level with philosophical spaces, it really made a difference. There was a uniform that appeared to pervade the philosophical milieu against which my presence in fashion, comportment, and body fell short. It was at SPEP that I found myself able to take up becoming a philosopher; it was among the feminist here that I could begin to think and take up the question of race. For me, it was always easier to talk about race among the Continental feminists than in the larger population of SPEP. But it was also during this time, as it seems to me now, that race as a relevant and important philosophical topic was beginning to flourish in Continental circles, and thus SPEP as a whole appeared much less hostile than the APA venue, though not wholly without hostility to the exploration of race. The Color of Change in Continental Feminist Philosophy

Real intersection points of piecewise algebraic curves

The piecewise algebraic curve, as the set of zeros of a bivariate spline function, is a generalization of the classical algebraic curve. In this work, we present an algorithm for computing the real intersection points of piecewise algebraic curves. It is primarily based on the interval zeros of the univariate interval polynomial in Bernstein form. An illustrative example is provided to show that the proposed algorithm is flexible.

Wind tunnel measurements of pollutant turbulent fluxes in urban intersections

Wind tunnel experiments have been carried out at the EnFlo laboratory to measure mean and turbulent tracer fluxes in geometries of real street canyon intersections. The work was part of the major DAPPLE project, focussing on the area surrounding the intersection between Marylebone Road and Gloucester Place in Central London, UK. Understanding flow and dispersion in urban streets is a very important issue for air quality management and planning, and turbulent mass exchange processes are important phenomena that are very often neglected in urban modelling studies. The adopted methodology involved the combined use of laser Doppler anemometry and tracer concentration measurements. This methodology was applied to quantify the mean and turbulent flow and dispersion fields within several street canyon intersections. Vertical profiles of turbulent tracer flux were also measured. The technique, despite a number of limitations, proved reliable and allowed tracer balance calculations to be undertaken in the selected street canyon intersections. The experience gained in this work will enable much more precise studies in the future as issues affecting the accuracy of the experimental technique have been identified and resolved.

Real two-dimensional intersections of a quadric by a cubic

The paper is devoted to finding the rigid isotopy classes of real projective surfaces that are obtained from nonsingular cubic sections of a chosen nonsingular real quadric. The result thus obtained is used to find the topological type of the real part of the Fano variety for the last rough projective class of real four-dimensional cubics which remained not investigated.

Image-processing algorithms for detecting and counting vehicles waiting at a traffic light

suboptimal traffic management, with unnecessary delays, higher fuel consumption, and higher emissions. Traffic management can be improved by installing inductive loops; however, installation involves temporary road closures and high maintenance costs, especially if there is normally a lot of heavy traffic on the road. We present a vehicle detection and counting system based on digital image-processing techniques. These images can be taken by digital cameras installed at the top of existing traffic lights. By using the proposed approach, it is possible to detect the number of vehicles waiting on each side of the intersection, hence, providing the necessary information for optimal traffic management. Results achieved after testing this methodology on three real intersections are promising, attaining high accuracy during the day (98.8%) and the night (91.3%) while counting several vehicles at the same time. Hence, the system is equivalent to installing multiple inductive loops in all the streets of the intersection, but with lower installation and maintenance costs. After integrating the proposed algorithms into a traffic-management system, it was possible to reduce fuel and CO2 emissions by half compared to the standard fixed-time scheduler.

Optimization Simulation Design of Sign Intersection Control

This project has operated the traffic survey, collected and analyzed the data， found the congestion of the road and optimized it, alleviated the congestion, evacuated the traffic jams. Taking real intersection as example， this paper records the traffic flow and timing control, analyzes traffic condition. At the last, this study simulates the traffic operation status under the present condition with traffic simulation software VISSIM and improves the signal timing.

Implementation of Two-step Crossing System with Cycle-time Reduction: The Effects and Future Tasks

In Japan, and also in other Asian countries, intersections with very long signal cycle time have been problematic especially form pedestrian viewpoint. This research aims to suggest a technique to solve the problems: 2-step crossing system with cycle time reduction, as a new standard of intersection design in Japan and other Asian countries as well. To check the effects of it, an experimental attempt are conducted in a real intersection and analyzed through a video survey and an interview survey. As a result, the authors revealed how much the effect differs by pedestrian walking direction and that lots of pedestrians accept this kind of experiment and think about the future extension. For future task, installing sound signals and remaining-time indicators, and applying different cycle time will be necessary to make this technique new Asian standard of intersection designing and controlling.

On the intrinsic complexity of point finding in real singular hypersurfaces

In previous work we designed an efficient procedure that finds an algebraic sample point for each connected component of a smooth real complete intersection variety. This procedure exploits geometric properties of generic polar varieties and its complexity is intrinsic with respect to the problem. In the present paper we introduce a natural construction that allows to tackle the case of a non-smooth real hypersurface by means of a reduction to a smooth complete intersection.

Analysis of Off-Peak Traffic Signal Operations

Abstract A traffic signal plays a major role in the overall safety and efficiency of traffic operations at an intersection. The type of operation strategy and signal timings utilized is typically based on the designed operation of the intersection at a desired Level of Service during peak traffic conditions. However, the same strategy could cause extensive vehicle delay as well as safety and security problems when lower traffic volumes are present. The main objective of this study is to define the existing off-peak issues and propose solutions to mitigate those issues. It also entails an evaluation of different traffic signal operation strategies which can be deployed to mitigate the off-peak issues. Computer simulation was utilized to optimize volumes ranging from 5 to 30 percent of peak traffic volumes on one hypothetical and two real intersections. All results showed drastic improvement on such measures of effectiveness as delay per vehicle, average speed, emission, and number of stops.

Delay Model of Adaptive Signal Control Using Fixed Number Theory

Considering the fact that the delay model of adaptive signal control derived from the stable theory cannot reflect the dynamic status of the traffic flow from each approach at an intersection, this paper uses the Fixed Number Theory and considers the dynamic traffic flow arriving process from each approach at the intersection. Subsequently, a new delay model is proposed according to the characteristics of Markov, to determine the vehicle's average delay for a certain period under a self-adaptive signal control condition, by simplifying the arrival form of traffic flow and simulating the reasoning for the Delay triangle. On the basis of the simulation platform of OPAC (Optimized Policies for Adaptive Control), the survey data from real intersections is used as the input, and the comparative analysis between the calculation results of the delay model and the traffic simulation results indicate that the proposed delay model is more effective than the model based on the stable theory, in objectively reflecting the operation of the traffic flow at the intersection.