Traffic Roundabout Research Articles

From Colleagues to Critical Friends: Exploring Avenues of Professional Learning to Support Equity-Based Pedagogies in Mathematics Education

ABSTRACT This article describes a collaborative self-study of seven early career mathematics teacher educators. Our collective group sought to improve our practice in, and enhance transparency around, supporting prospective teachers as they engaged in equity-based mathematics pedagogies. The collaboration evolved into a critical friendship and provided a space to study, reflect and supportively challenge our practices. We found that self-study methodology matched our motivation to improve our practice as teacher educators, while recognizing the contexts of our other professional and institutional obligations and upholding our own values. We draw upon a traffic roundabout as a metaphor for our experience in self-study, noting the ways it provided professional learning and moved our work with prospective teachers forward.

Photocatalytic Synthesis of Acetals and Ketals from Aldehydes and Silylenolethers without the Use of Acids.

Invited for the cover of this issue are Desirée Steuernagel and Hans-Achim Wagenknecht at the Karlsruhe Institute of Technology. The image depicts a traffic roundabout, which symbolizes the photocatalytic cycle for the conversion of aldehydes and silylenolethers as starting materials into their acetals. Read the full text of the article at 10.1002/chem.202203767.

Towards IoT monitoring of street-side monuments: the Florentine Dietrofront as a case study

The need for care often shown by ageing cultural heritage and the circumstantial lack of dedicated budget are increasingly calling for smart monitoring solutions to shift the maintenance paradigm from reactive-preventive to predictive. Monitoring artworks poses additional issues with respect to the more common industrial solutions, such as aesthetics, dealing with unusual materials, remote locations (archaeology), etc. In this scope, the “Dietrofront” statue in Florence, by artist Michelangelo Pistoletto, is an emblematic instance. Installed on a traffic roundabout, it comprises four travertine blocks, one of which hangs 5 m above the ground supported by a steel structure which has shown relevant symptoms of damage during the 2006 restoration works. During a later intervention, we seized the opportunity to equip the structure with a three IoT sensing devices, so as to monitor thermo-hygrometric conditions, inclination and vibrations of the structure. Various issues common to outdoor monuments have been faced, such as the need for visual non-intrusiveness and the unavailability of power supply. A small wireless sensor network was designed and installed, also exploiting an existing room inside the nearby mediaeval city gate. The network is fully solar-powered by photo-voltaic modules integrated on both the statue and the gate and not visible from the street. The data obtained have been analysed and compared to a simple lumped-parameters structural model, so as to estimate the relevance of traffic-induced vibration on the steel structure. The risk of water vapour condensation has also been assessed.

Ground Level Ozone Formation Near a Traffic Intersection: Lisbon “Rotunda De Entrecampos” Case Study

Ground-level ozone in cities is increasing mainly due to traffic exhaust aftertreatment devices, i.e., tailpipe catalytic converters. The chemical reaction of O3 formation indicates radiation and nitrogen oxides as main players. Thus, we investigate correlations between O3, global radiation, nitrogen oxides, temperature, and precipitation in several periods of the year (2017) near a traffic roundabout in Lisbon city (coordinates 38°44’55’’ lat, −9°08’56’’ long). The weekend effect, school break versus school period, day and night, and seasonal effect were explored. Low-cost sensors (LCS) of O3, NOx, and temperature were tested to see if they can be used to get historical data on other cities and locations. The main innovation is the calibration of the sensor directly with real data (uncontrolled environment). Raw data were compared and led us to conclude that MQ-131 has a better performance than the MICS-4514 sensor. The results indicate that the diurnal cycle of ozone concentration has a mid-day peak around 1–2 pm and a lower nighttime concentration below 5 ppb Weekends and school break period (251 days a year) have the highest values of Ozone, this is due to lower NOx emissions and thus lower levels of ozone destruction reaction (NOx-titration reaction). August is a hotspot month with a maximum concentration of 71 ppb.

Analisis Kinerja Rencana Bundaran dengan Pendekatan Simulasi Mikro

Urban road network typically consists of many intersections which commonly lead to traffic problems. In relatively low traffic, a simple priority intersection will be sufficient and lead no traffic problem without necessarily implement traffic lights, roundabout or others. In an urban area where traffic demands are high, intersections need to be treated with an accurate traffic engineering approach. There are many different approaches to reduce the traffic problem in intersection including traffic light, roundabout, or interchange. Cimahpar Raya street and Indobaso intersections are urban areas in Bogor city with the high demand for transportation and often having a congestion problem in peak hour. The Office of Public Works and Spatial Planning (PUPR) of Bogor city plans to develop and change the Indobaso intersection to be a roundabout, while also increasing the lane width of the approaching roads. This study was conducted to assess the performance changes of the Indobaso intersection improvement by developing a traffic model of the intersection. The planned roundabout and lane width improvement significantly reduce the traffic delays by 90,07%, reduce travel time by 51,76%, improve average speed by 83,77%, and reduce the traffic density by 88,54% compared to the current condition of the intersection which lacks required lane road width and maneuver area.Key words: urban road, intersection, traffic model

Regression analysis with compositional data using orthogonal log-ratio coordinates

Compositional data frequently arise when data refer to components which are proportions or fractions of a whole. Within the log-ratio approach, the analysis of compositional data can be conducted in terms of log-ratio transformations of components. These transformations make it possible to overcome the problem of the constant-sum constraint, making standard statistical methods applicable. In the present work, the log-ratio approach based on orthogonal log-ratio coordinates is adopted to show how it can lead to considerable improvements in the interpretation of the results of regression modeling with compositional data, both as explanatory or response variables. In order to demonstrate its practical usefulness, the methodology presented in this paper is applied to the analysis of air pollution produced by vehicles traveling through road intersections, with a specific focus on the effect of the type of traffic control (traffic signal vs. roundabout) on CO2 emissions.

Using Virtual Reality to Assess the Street Crossing Behavior of Pedestrians With Simulated Macular Degeneration at a Roundabout

This work investigates how pedestrian street crossing behavior at a virtual traffic roundabout is affected by central visual field loss. We exposed participants with normal vision to a first-person virtual experience of central visual field loss of variable size in the form of a simulated scotoma, an area of the visual field with degraded visual acuity. A larger size of scotoma influenced people to select longer gaps between traffic, and to wait longer before initiating a crossing. In addition, a gender difference was found for risk taking behavior. Male subjects tended to take more risk, as indicated by the selection of shorter gaps in traffic and a shorter delay before the initiation of a crossing. Our findings generally replicate those of studies done in real-world conditions using participants afflicted with genuine central vision loss, supporting the hypothesis that virtual reality is a safe and accessible alternative for investigating similar issues of public concern.

Numerical simulation of pollutant dispersion characteristics in a three-dimensional urban traffic system

A complex three-dimensional (3D) urban traffic system containing roundabouts and tunnels continues to emerge in China's metropolises. Based on this, a mathematical model was established to describe the fluid flow and CO propagation characteristics in a complex 3D traffic system, including a sunken bus stop area, traffic roundabout, viaducts, and tunnels. Features of pollution dispersion in those locations were analyzed under different ambient crosswinds (ACWs). The results showed that the distribution of pollutants in the 3D traffic system was greatly influenced by geometric parameters and their relative positional relationship. Distribution of pollutants in the 3D traffic system is rather complicated and varied. At a sunken bus stop area, changes in ambient wind will cause fluctuating pollution levels upstream and downstream at the bus stop, and symmetrical distribution has been exhibited under parallel wind. The effects of complex road conditions on pollutants are beyond the prevailing winds at the traffic roundabout. In a naturally ventilated municipal double-hole traffic tunnel, contaminants accumulate along the downstream direction, which is more pronounced at low wind speeds. However, dilution effects are enhanced in tunnels' open areas.

<b>THE SNAKE AND THE ROUNDABOUT: ETHICAL PARTICULARISM AND THE PATTERNS OF NORMATIVE INDUCTION</b><br/>A SERPENTE E A ROTUNDA: PARTICULARISMO ÉTICO E OS PADRÕES DA INDUÇÃO NORMATIVA

Using two examples of ethical choice, Philippa Foot’s snake and the traffic roundabout, this paper offers an account of normative induction that characterizes particularism and generalism as stages of normative inquiry, rather than rival accounts of moral knowledge and motivation. Ethical particularism holds that the evaluative cannot be “cashed out” in propositional form, and that it is descriptively “shapeless.” Drawing on examples from law, this paper claims that, while individual normative inquiry may be viewed as encountering a shapeless particularist context of seem-ingly unlimited nonmoral properties, normativity is driven by repe-tition of similar situations toward shared practices and descriptive predication. Rather than retention of epistemic status by defeated reasons, this illustrates retirement of relevant properties and ac-companying reasons, transformation of the reasons environment, and a pluralist normative ontology.

Research on VSP Microcosmic Emission Model and Numerical Simulation for Motor Vehicle

The paper has first built the vehicle-borne computer sensing integration testing system experiment platform, through the actual road test experiment, collects the different mobile vehicle the operating condition data and emission data, has constructed the different vehicle instant exhaust emission rate and database of vehicles driving cycle-based data correspondence, Establishes the driving cycle and road grade power density microscopic emission model. Uses the typical path roundabout crossing as an example, the paper carries on the power density computation through microscopic simulation software numerical simulation output roundabout crossing region vehicle bicycle the real-time speed, acceleration and other travel data, combined with the previous microscopic emission model of building, calculates the instantaneous mass emission rate and vehicles total emission of roundabout crossing different vehicles pollutant gas. According to the result of software simulation and numerical computation, the paper effectively appraises the regional road roundabout pollution emitted by vehicles, has verify the validity of the in-vehicle computer sensor integration testing and emission assessment model, provide a reference for seeking to solve regional traffic roundabout environmental pollution testing methods and effective assessment.

Space and time resolved monitoring of airborne particulate matter in proximity of a traffic roundabout in Sweden

Concerns over exposure to airborne particulate matter (PM) are on the rise. Currently monitoring of PM is done on the basis of interpolating a mass of PM by volume (μg/m3) but has the drawback of not taking the chemical nature of PM into account. Here we propose a method of collecting PM at its emission source and employing automated analysis with scanning electron microscopy associated with EDS-analysis together with light scattering to discern the chemical composition, size distribution, and time and space resolved structure of PM emissions in a heavily trafficated roundabout in Sweden. Multivariate methods (PCA, ANOVA) indicate that the technogenic marker Fe follows roadside dust in spreading from the road, and depending on time and location of collection, a statistically significant difference can be seen, adding a useful tool to the repertoiré of detailed PM monitoring and risk assessment of local emission sources.

Application of Simulation Methods for Evaluating the Sea Waterways Traffic Organisation

Maritime transport is of great importance as it is the basis of international trade. Shipping is a global industry and highly complex business. Further safety development at sea is determined by the growth of maritime traffic intensity. Therefore, new ideas and technologies are needed to optimize the sea transport system. In the paper, the cellular automaton model is suggested to describe traffic flow at grade roundabout and simple crossing. Not only the cell state but also neighborhood as well is defined for presented cellular automaton. The model, describing vessels motion, takes into account vessel’s type, speed and length, vessel’s behavior and maneuverability, lane status, and flow density. It provides the basis for simulation. Two types of traffic schemes, namely, roundabout and simple routes crossing, are considered. Some results of simulation, including ships safety prediction, illustrate possible applications for evaluation of maritime traffic organization. Final conclusion and remarks outline further work development.

An open-terrain line source model coupled with street-canyon effects to forecast carbon monoxide at traffic roundabout

A double-lane four-arm roundabout, where traffic movement is continuous in opposite directions and at different speeds, produces a zone responsible for recirculation of emissions within a road section creating canyon-type effect. In this zone, an effect of thermally induced turbulence together with vehicle wake dominates over wind driven turbulence causing pollutant emission to flow within, resulting into more or less equal amount of pollutants upwind and downwind particularly during low winds. Beyond this region, however, the effect of winds becomes stronger, causing downwind movement of pollutants. Pollutant dispersion caused by such phenomenon cannot be described accurately by open-terrain line source model alone. This is demonstrated by estimating one-minute average carbon monoxide concentration by coupling an open-terrain line source model with a street canyon model which captures the combine effect to describe the dispersion at non-signalized roundabout. The results of the modeling matched well with the measurements compared with the line source model alone and the prediction error reduced by about 50%. The study further demonstrated this with traffic emissions calculated by field and semi-empirical methods.

Capacity evaluation of multi‐lane traffic roundabout

AbstractThe entry capacity at a traffic roundabout is typically evaluated for each entry approach, considering the circulating flow and geometric characteristics, e.g., the US highway capacity manual model and the UK Linear Regression model. These models are not appropriate for analyzing multi‐lane roundabouts because they do not take into account the possible unequal traffic distribution between the circulating lanes. This paper introduces a lane‐based methodology that evaluates the entry capacity for each individual lane while considering the traffic distribution on the circulating lanes. The arrival and circulating flows are formulated based on drivers' lane choice patterns. We then modify and extend the formulae from existing models for the analysis of capacity of multi‐lane roundabout. Based on the analysis, we show that higher capacity can be achieved when the utilization on the circulating lanes is more balanced. This result can lead to improved design and management techniques to increase the capacity of multi‐lane roundabout. Copyright © 2010 John Wiley & Sons, Ltd.

Uncertainty in modelling PM10 and PM2.5 at a non-signalized traffic roundabout

Uncertainty in inputs to most air quality models of causal nature often results uncertainty in modelled concentrations as well. If incorporated, it may provide complete information on assured range of air pollutant levels. The study presents a sensitivity analysis of models and the probabilistic based estimates of uncertainties in their predictions. Two vehicular exhausts dispersion models have been used for forecasting hourly average PM10 and PM2.5 concentrations at a non–signalized roundabout traffic intersection. The uncertainties were estimated using first–and second–order Taylor series and Monte Carlo methods due to wind speed and wind direction and evaluated with one week particulate matter measurements (PM10 and PM2.5) during winter period. The amount of uncertainty due to wind speed was about 55% in the both models, resulted from wind direction was up to 5 to 20% of the modelled mean for receptors closer to the source but increased even up to 200% as the distance from the source increased. The uncertainty due to wind speed by second–order Taylor series matched with that by Monte Carlo method implying that a simple second–order Taylor series can be utilized for such studies instead of conventional time–taking Monte Carlo method.

‘Bikes are Such a Nuisance’ – Visually Impaired People Negotiating Public Space in Groningen

Groningen, the seventh largest city of the Netherlands, has a long tradition of improving accessibility of its city centre. In 1977, the centre was radically modified by replacing a six-lane motorway with an increasingly car-free centre (Nicholson-Lord, 1993; see Tsubohara and Voogd, 2004 for extensive discussion) with a central market square, reclaimed from a traffic roundabout. The leftist city council of Groningen has since promoted the use of bicycles and provided the necessary infrastructure (bicycle paths and public transportation) in a top-down procedure which virtually excluded target groups or social organisations. This approach was initially heavily opposed by shopkeepers until they realised the positive impact of the council’s measures on their profits in the mid1980s and began to pressure for more pedestrian areas (Bratzel, 1999). In order to keep the city accessible, policy developments and city planning were based on the principles of the ‘compact city’ which intended to restrict suburban sprawl by shortening distances between residential areas, the workplace, and locations for shopping (P. Allen, 1994; Bloemkolk and Huis in’t Veld, 2001). As a result, more than 50% of Groningen’s 182,000 residents use the bicycle as a key means of transportation making Groningen the Dutch city with the most bike trips per day (Centraal Bureau voor Statistiek, 2007). In 1993, an American Bicycle magazine already labelled Groningen the Number 1 bicycle city of the world and

Circulatory Markings at Double-Lane Traffic Roundabout: Comparison of Two Marking Schemes

This paper compares two types of circulatory markings at a double-lane traffic roundabout: the concentric marking scheme and the Alberta marking scheme. The effects of these two marking schemes on drivers' lane choice behavior, delay, and safety, are compared based on data collected from before and after field surveys over a period of 2 years. The results showed that the Alberta marking scheme could better balance the traffic flows on the two circulatory lanes, resulting in higher performance levels.

Phase diagram of a traffic roundabout

We propose a simple cellular automaton model to study the traffic dynamics in a roundabout. Both numerical and analytical results are presented. We are able to obtain exact solutions in the full parameter space. Exact phase diagrams are derived. When the traffic from two directions mixed, there are only five distinct phases. Some of the combinations from naive intuition are strictly forbidden. We also compare the results to a signaled intersection.