Roundabout Intersection Research Articles

Proposals for the reorganization of road traffic in the central area of Pitesti municipality based on microsimulation-performed traffic analyses

In order to identify the possibilities for solving the traffic problems in the central area of Pitesti municipality - from improving traffic-light intersections to the proposal to redirect some of the traffic flows outside the area under analysis - a Vissim application, consisting of a microsimulation of road traffic in the central area, was performed. Based on the research conducted, a perspective of great interest proved to be the identification of the possibilities by means of which, to an extent as large as possible, the road traffic coming from Calea Depozitelor or the bridge over Arges and going to the Maior Sontu traffic-light intersection should follow the route between the railway and the Arges River, so as to reduce the impact load on the Podul Viilor roundabout intersection and circumvent the central residential area of the municipality of Pitesti. But, in the long run, the only viable solution that will completely eliminate the traffic congestion phenomenon at Maior Sontu intersection is to create the conditions for redirecting some of the traffic flows, and this can be done by arranging a road passage over the railway in the Prundu neighbourhood. Thus, a significant part of the road traffic - the one going to the Prundu, Craiovei and Războieni neighbourhoods, as well as to the periurban area in the east and south of the city, will follow this route, thus alleviating the traffic in the central area of the municipality of Pitesti.

Roundabout performance analysis in the city of Medan

Medan city as one of the largest cities in Indonesia, currently has problems in the field of transport is quite worrying. Like the other cities in Indonesia, the growth of traffic volume can not be followed by improvement of existing infrastructure. It is characterized by frequent traffic jams, long queues and delays contained in the segment or intersection. One type of arrangement is a roundabout intersection. Roundabout intersection canalization is composed of a central circle surrounded by a one-way street. Roundabout can act as a controller, divider and guidance for the traffic system which rotates in the direction. This study aims to determine the performance of the roundabout on the road Ir. Haji Juanda, Medan. Analyses were performed to obtain the performance of these intersections. Analyses were performed by using a calculation method MKJI 1997 and the Australian Road Research Board (ARRB) manually. The performance measures analyzed in the form of the degree of saturation, delay and queue opportunities using the method MKJI 1997. whereas the ARRB method, the calculated performance of the roundabout is the degree of saturation and delay. Good infrastructure handling can create a reduction of delay, and congestion, so that it can reduce pollution and support a more green environment.

Design of a rotary for an uncontrolled multi-leg intersection in Chennai, India

One way to control the traffic at busy intersections is to construct a roundabout or rotary intersection, which is a special type of at-grade intersection, where all converging vehicles are forced to move round a central island in clock-wise direction. The present study aims to design a rotary for an uncontrolled multi leg intersection located in Royapetah in Chennai, India. The intersection has five approach roads with two-way traffic in all the approach roads and there is no signal or traffic police to control the traffic at present and hence experiences traffic chaos during peak hours. In order to design the rotary, it is essential to have the information on traffic volumes coming from the approach roads. For this, a video data collection was carried out for a duration of eight hours from 7.30 am to 11.30 am and from 2.30 pm to 6.30 pm on a typical working day using a handycam from the terrace of an apartment building located near the intersection. During data extraction stage, each 5 min. traffic volume was extracted for all the five classes of vehicles considered and were converted to passenger car units (PCU). The analysis of traffic data showed that during peak hour from 4.45 pm to 5.45 pm, the proportion of weaving traffic, i.e., ratio of sum of crossing streams to the total traffic on the weaving section was found to be 0.81. According to Indian road congress (IRC) guidelines, this proportion can take any value between 0.4 and 1 and in the present study, the calculated value is found to be within the prescribed range. Using the calculated values of average entry width of the rotary and width & length of weaving section, the practical capacity of the rotary was found to be 3020 PCUs which is well above the observed traffic volume of 2665 PCUs.

Dynamic traffic noise assessment tool: A comparative study between a roundabout and a signalised intersection

Considering traffic flow as a steady noise source is common practice when studying traffic alternatives and its impact on the sound environment. However, vehicle dynamics have a strong influence on both transport behaviour and noise emission. One of the most relevant elements of traffic design is the intersection, where replacement of crossing intersections with roundabouts is common. In order to understand the features of these two traffic configurations, microscopic approaches are needed, making it possible to study time-pattern fluctuations relevant for the urban sound environment perception. A model based on individual-vehicle characteristics as function of time is developed and implemented in a real case study at a development stage. The model incorporates state-of-art microscopic traffic simulation software combined with the recent noise emission model, CNOSSOS-EU, applied through an in-house developed dynamic traffic noise tool, including both internal combustion engine and all-electric vehicles at different traffic flows. The tool is described in general terms incorporating the randomisation of source power. The propagation considers a flat-city configuration up to 100m range. The tool enables study of different statistical indicators, including descriptors of probability density functions, calm periods through the novel indicator Centre of Mass Time (CMT) and noise events. The outcomes are presented through graphs and maps explaining traffic disruptions, acceleration effects, vehicle configurations and flows, source strengths, contribution and difference maps. Among the results, it is shown that, for the signalised crossing, the acceleration of the simulated traffic has a large effect on the source strength. It is however also shown that, for an unbalanced roundabout intersection leading to congestions, it can become noisier than the signalised crossing. It is furthermore shown that, when reducing the traffic flow, the two intersection types behave more similarly; however the roundabout having the best performance for the majority of the studied analysis. Further results are shown, e.g. for removing heavy vehicles, removing also medium heavy vehicles and assuming only all-electric light vehicles, including analysis from using various indicators. A discussion about the presented tool, the current results and ideas for future work concludes the paper.The present paper goes along a series of studies with the overall intention to provide a more solid basis for justifying decisions in traffic planning regarding the outdoor sound environment.

Particulate matter urban air pollution from traffic car

The particulate matters (PM) are very important compounds of urban air pollution. There are a lot of air pollution sources who can generate PM and one of the most important of them it is urban traffic car. Air particulate matters have a major influence on human health so everywhere are looking for PM reducing solutions. It is knows that one of the solution for reduce the PM content from car traffic on ambient urban air is the fluidity of urban traffic car by introduction the roundabout intersections. This paper want to present some particulate matter determinations for PM10 and PM2.5 conducted on the two types of urban intersection respectively traffic light and roundabout intersections in Baia Mare town in the approximate the same work conditions. The determinations were carried out using a portable particulate matter monitor Haz – Dust model EPAM – 5000, who can provide a real time data for PM10, PM 2.5.Determinations put out that there are differences between the two locations regarding the PM content on ambient air. On roundabout intersection the PM content is less than traffic light intersection for both PM10 and PM 2.5 with more than 30%.

Study of the opportunities of analytical determination of the origin-destination flows in roundabout intersections based on data provided by fixed observers

For the purposes of the analysis of road traffic at the level of the area surrounding a roundabout intersection there are times when the flows of Origin-Destination (O-D flows) of the respective intersection are of interest - when it is not possible to improve the level of service of the intersection by means of increasing its capacity, but only by diverting some traffic flows from the respective area. Currently, the determining of these O-D flows is based on video recordings of the intersection traffic, followed by laborious and lengthy analyses of the images obtained. But a prolific way, yet not explored in specialised literature, can be the identification of the analytic relations between O-D flow volumes and the volumes of the intersection traffic flows that can be measured by fixed observers (incoming flows, outgoing flows and conflict flows). As a result, this paper presents the research conducted to identify the possible relationships between these deterministic O-D flows and the flows that can be measured by fixed observers. It was demonstrated that, when performing measuring of the flow of vehicles that turn right with fixed observers, there will be analytical deterministic relationships for the 3-armed intersection with return flows, as well as for the 4-armed intersection without return flows. This means that, for 3-armed intersections with return flows and for 4-armed intersections without return flows, it is possible to fully know the O-D flows based on the flows measured by fixed observers (compulsorily involving right-turn flows), which is an absolutely exciting and unique achievement, as knowing these Origin-Destination flows will allow better regulation of the traffic in the area where the roundabout intersection is, in order to facilitate the upstream diversion of some of O-D flows passing through the roundabout intersection.

Technical and Economic Evaluation of Pinavia Interchange in Comparison with Roundabout Intersection by AIMSUN

Interchanges that are investigated in this research are roundabout interchange and pinavia interchange that are simulated in AIMSUN software using traffic data. The parameters that are considered for each interchange are traffic volume, pollutant emissions, fuel consumption, travel time, delay time ,construction cost, repair and maintenance cost, travel time cost , fuel consumption cost and safety , so that in technical evaluation traffic volume, pollutant emissions, fuel consumption, travel time, delay time are compared by using two independent sample t – test that are used for comparing of two group of data and It is assumed that the variances are equal . Then In economic evaluation construction cost, repair and maintenance cost, travel time cost , fuel consumption cost and safety are converted into cost by using axis produce way that based on this supposal that storage in exchange for an hour of travel time, increase an hour of production opportunities and construction cost, repair and maintenance cost calculated by executive plans and Related Regulations and finally each parameter is weighted by AHP and obtain the universal (total) cost. Finally due to the total cost of the resulting it can be seen that for twenty-year period pinavia interchange in compare with roundabout interchange has 49% more efficient.

Cooperative Intelligence in Roundabout Intersections Using Hierarchical Fuzzy Behavior Calculation of Vehicle Speed Profile

In this paper, a new fuzzy-behavior-based algorithm for roundabout intersection management is presented. The algorithm employs cooperative intelligence and includes intelligent vehicles and infrastructure to calculate speed profiles for different vehicles, in order to achieve more comfortable driving profiles, as well to reduce congestion and CO 2 emissions. The algorithm uses adaptive spatio-temporal reservation technique and was tested in MATLAB/Simulink environment. The algorithm is designed to function in different scenarios with both cooperative and non-cooperative vehicles, as well as optional intersection infrastructure. Results have show that using the proposed algorithm different vehicle communication types can be successfully combined in order to increase traffic flow through roundabout intersections.

EVALUATING THE OPERATIONAL AND THE ENVIRONMENTAL BENEFITS OF A SMART ROUNDABOUT

Vehicle fuel consumption and emission rates in Kuwait have increased considerably over recent decades, and are now causing health and economic problems. A three-lane smart roundabout is a new and innovative design idea that can help to mitigate these issues. The smart roundabout was designed with a dedicated exit lane on the right side of each entryway, and a U-turn path connecting each adjacent entry and exit road. Both features permit vehicles to turn in specific directions without needing to enter the roundabout itself. Underground tunnels were designed for pedestrian and cyclist use. The objective of this study was to measure the impact of a smart roundabout on vehicle fuel consumption and on emissions of carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons. These results were then compared with those of a traditional roundabout and of a light-signalised intersection. Two light-signalised intersections with different traffic volumes were chosen for this study and simulated in their present state, as replaced by traditional roundabouts; and as replaced by smart roundabouts using the SIDRA 6.0 software. The smart roundabout allowed traffic to proceed with minimal delay and idling time, significantly reducing vehicle fuel consumption and emissions in comparison with a traditional roundabout or light-signalised intersection. Furthermore, the smart roundabout allowed pedestrians and cyclists to move safely through the intersection without interacting with vehicular traffic

Integrating Roundabouts with Freight Roadway Networks

The demand for freight transportation in the United States has grown rapidly in the past couple of decades; the rate at which the highway capacity is growing is not able to meet the freight-trans- portation needs, resulting in congestion and delay, ultimately affecting the users and the public with increased prices for the goods delivered, unreliable delivery times, and air-pollution concerns. Freight bottlenecks are a major cause of recurring congestion which accounts for about 40% of total vehicle hours of delay in the United States. Intersections for urban freight-roadway networks are one of the major freight bottlenecks and are considered to be a significant contributor for congestion and delay. Improving the efficiency at urban intersections with high truck traffic can address the freight-traffic congestion, leading to optimized goods movement as well as decreased delays, congestion, and emissions, thus enhancing the air quality in and around the communities. With the roundabout intersection control being proven as a safe, operationally efficient, and environment-friendly control treatment, a greater use of roundabouts with urban freight- roadway networks and their feasibility is analyzed in this study. The control for most urban intersections is a signalized treatment; a performance analysis is conducted for selected signalized intersections in urban freight-roadway networks, comparing the intersections by adapting a roundabout control theoretically using SIDRA (signalized and un-signalized intersection design and research aid) Intersection software. Various parameters, such as the intersection’s level of service, the effective intersection capacity, the average control delay, vehicular emissions [carbon dioxide (CO2), hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx)], the intersection’s annual delay, and the intersection’s annual cost, are selected for comparison.

제주지역 다지교차로의 회전교차로 교통시스템 변환에 따른 효과분석

회전교차로는 평면교차로의 일종으로 교차로 중앙에 원형교통섬을 두고 교차로를 통과하는 자동차가 원형교통섬을 우회하도록 하는 교차로 형식이다. 본 연구에서는 신호교차로와 회전교차로의 운영 및 경제적 효과를 분석하기 위해서 제주지역의 5개 교차로를 중심으로 회전교차로 설치에 따른 비교 분석을 실시하였다. 분석 결과, 차량평균지체 측면에서 신호교차로에 비해 회전교차로가 65.6%%에서 91.77%의 개선효과가 있는 것으로 분석되었다. 차량운행비용과 시간가치비용을 종합한 교통혼잡비용의 효과를 분석한 결과, 년간 58.59%(D intersection)에서 81.69%(B intersection)의 비용절감 효과가 있는 것으로 분석되었다. 이를 통해 제주지역의 경우 신호교차로에 비해서 회전교차로가 운영 효과가 뛰어난 것으로 조사되었다. Roundabout is an intersection that allows vehicles to pass through the intersection by circulating the circular traffic island at the center of the intersection. In this study, a comparative analysis was conducted on roundabout at five locations in order to deduce the operational result and financial effect of roundabout and signal intersection. As for the operational result, it was found that roundabout showed improvement effect in the average delay per vehicle compared to that of signal intersection by minimum of 65.6% and maximum of 91.77%. it was found that roundabout showed financial cost-saving effect in the traffic congestion cost compared to that of signal operation by minimum of 58.59% and maximum of 81.69% per year. It can be known from these analysis results that roundabout has significant operational effects under certain amount of traffic volume by allowing vehicles to pass through the intersection in a continuous way without much waiting time and stoppage from signal control.

Evaluation of Roundabout and Signalized Intersection Designs using Microsimulation

Evaluation of Roundabout and Signalized Intersection Designs using Microsimulation

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.

Carbon monoxide levels along roadway

This paper predicts and compares the carbon monoxide (CO) concentration levels along Sembulan Road for years 2004 and 2014 using CAL3QHC air dispersion model at two major locations, i.e., at Sembulan Roundabout and Sutera Harbour Intersection, Kota Kinabalu, Sabah, Malaysia. The CO concentration “hot-spots” were also identified at Sutera Harbour Intersection, and the highest maximum 1-hr average ground level concentrations of CO modeled for Kpg. Air Sembulan located in the northeast of idling road was 9.33 ppm for year 2004. This study showed that there would be no extreme changes in CO concentration trends for year 2014 although a substantial increase in the number of vehicles is assumed to affect the level of CO concentrations. It was also found that the CO levels would be well below the Malaysian Ambient Air Quality Guidelines of 30 ppm for 1-hour Time-Weighted Average (TWA). Comparisons between the modeled and observed outputs using quantitative data analysis technique and statistical methods indicated that the CAL3QHC predicted results correlated well with measured data. It was predicted that receptors located near to the major intersection, in the long-term would be potentially exposed to relatively higher CO levels.

VEHICLE MOVEMENTS AND INTERACTIONS AT ROUNDABOUT INTERSECTIONS.

The paper examines the circulating paths of vehicles at roundabouts and also methods of evaluating capacities of such layouts. The work of Al-Alawi in investigating the lateral placement of circulating vehicles is detailed. In this work time-lapse cine recording techniques were employed to obtain details of vehicle paths and gap acceptance operations. This observed merging decision-making was classified and mean lag and standard deviation determined. Using the results of this analysis a computer model of traffic flow at a roundabout intersection was developed. The model can be used to simulate a roundabout with up to five approaches with a maximum of five lanes on each approach. The object of the model was to investigate traffic flow at roundabouts when for short periods demand exceeds capacity. It is considered that the model is capable of realistically simulating traffic behaviour at roundabouts when predictions of vehicle paths can be made within the circulating area. (TRRL)