Relevant bibliographies by topics / Roundabouts

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
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Academic literature on the topic 'Roundabouts'

Author: Grafiati
Published: 4 June 2021
Last updated: 3 March 2023

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Journal articles on the topic "Roundabouts"

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Wankogere, Elisha Jackson, Valerian Kwigizile, Jun-Seok Oh, and Pavel Ikonomov. "Comparison of Driver Navigation at Turbo Roundabouts and Modern Two-Lane Roundabouts: Simulation Study." Transportation Research Record: Journal of the Transportation Research Board 2637, no. 1 (January 2017): 89–98. http://dx.doi.org/10.3141/2637-11.

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Roundabouts can be a solution to safety concerns common to conventional intersections. Recently in the United States, there has been an increase in the conversion of problematic intersections to roundabouts to improve their safety. However, there are some important considerations and challenges to make roundabouts safe for all users, especially multilane roundabouts. There may also be challenges for drivers to navigate a newly built or a new type of roundabout. Roundabout features such as pavement markings and signage play an important role in driver navigational performance. This research was an effort to evaluate new roundabout design and existing roundabout safety and operational features such as signs and pavement markings. The focus was on how such features influenced the performance of drivers, specifically at multilane roundabouts. Two-lane roundabouts and rotor turbo roundabouts were evaluated. A driving simulator was employed to test various simulation scenarios in a virtual world. The results indicate that lane keeping and higher navigation speeds are still problems at multilane roundabouts. The rotor turbo roundabout outperforms the two-lane roundabout in enabling correct lane choice and navigation speed control by drivers. Furthermore, it was found that roundabout signs and pavement markings used in the United States can be adopted for turbo roundabouts.
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Hatami, Hadi, and Iman Aghayan. "Traffic Efficiency Evaluation of Elliptical Roundabout Compared with Modern and Turbo Roundabouts Considering Traffic Signal Control." PROMET - Traffic&Transportation 29, no. 1 (February 3, 2017): 1–11. http://dx.doi.org/10.7307/ptt.v29i1.2053.

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This paper compared the performance of elliptical roundabout with turbo and modern roundabouts. It considers the effects of increasing the central island radius and speed limit on delay and capacity. Three types of roundabouts (modern, turbo and elliptical roundabouts) with different numbers of lanes (single lane, two-lane and three-lane) were designed. Unsignalized and signalized controls were applied for these roundabouts. The robustness of the designed roundabouts was investigated for saturated and unsaturated flow conditions. Based on the obtained results, increasing the central island radius had both positive and negative effects on delay and capacity. However, a positive effect on these variables was observed in all roundabouts when increasing the speed limit. In unsignalized and signalized control under unsaturated flow conditions, a modern roundabout had lower delay time than an elliptical roundabout. Moreover, in saturated flow, the elliptical roundabout had the best performance in terms of delay. Overall, in comparison with the turbo roundabouts, modern and elliptical roundabouts had the highest capacities in unsignalized and signalized controls. This study can provide useful information for engineers who decide to design a roundabout.
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Alluri, Priyanka, Albert Gan, Andres Diaz, and Ruth Steiner. "Safety Impacts of Access Management Features near Roundabouts." Transportation Research Record: Journal of the Transportation Research Board 2517, no. 1 (January 2015): 28–36. http://dx.doi.org/10.3141/2517-04.

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Roundabouts can better facilitate U-turns and provide better safety, especially in reducing severe crashes, than can traditional intersections. Roundabouts, instead of traditional signalized intersections, increasingly are being installed on busy arterial streets. Even though roundabouts gradually are becoming integral to regional transportation networks, no literature addresses the safety impacts of access management features such as driveways and median openings along corridors with roundabouts. The existing access management guidelines for signalized intersections are not directly applicable to roundabouts because traffic operations are different at the two types of intersections. In this study the safety impact of access features near roundabouts was investigated. In particular, three potential safety concerns associated with roundabouts were studied in commercial areas in Florida: (a) the impact of driveway corner clearances on roundabout safety, (b) the safety impact of median openings near roundabouts, and (c) the safety at roundabouts that provided direct access to activity centers. Data for the analysis reflected 131 roundabouts in commercial areas in Florida. Police reports for more than 1,000 crashes that occurred in roundabout influence areas between 2007 and 2011 were reviewed carefully to identify crash patterns and causes related to specific roundabout designs, con-figurations, and access features. Recommendations are made for access features near roundabouts in commercial areas.
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Flannery, Aimee, and Tapan K. Datta. "Modern Roundabouts and Traffic Crash Experience in United States." Transportation Research Record: Journal of the Transportation Research Board 1553, no. 1 (January 1996): 103–9. http://dx.doi.org/10.1177/0361198196155300115.

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Roundabouts have become popular in Australia and many countries in Europe during the past few decades. In the United States of America, however, roundabouts are just beginning to be recognized as an alternative treatment for roadway intersections. An effort was made to collect traffic and traffic crash data for existing roundabouts in the United States and to perform a statistical analysis to determine the effectiveness of roundabouts as a treatment for intersecting roadways. General information about thirteen roundabouts located in Maryland, Florida, Nevada, and California was collected and is included for readers’ use. In addition, six retrofitted roundabout sites with accident data ranging from 1 to 3 years before and after were analyzed. In all but one case, the reduction in accidents for roundabout sites was in the range of 60 to 70 percent. A chi-squared test and a normal approximation test were performed using the accident data from these six roundabout sites. Both of these tests indicated a significant difference in the reduction of frequency and mean of accidents at 95 and 99 percent confidence levels, respectively, between pre-roundabout and post-roundabout periods. Results, though limited, are encouraging and in line with findings of past European and Australian studies involving roundabouts. Additional studies on the safety performance of U.S. roundabouts should be conducted in the future when more data are available to reinforce these findings.
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Guerrieri, Marco, and Ferdinando Corriere. "Estimation of Measures of Effectiveness (MOE) for the C-Roundabouts." Applied Mechanics and Materials 459 (October 2013): 569–74. http://dx.doi.org/10.4028/www.scientific.net/amm.459.569.

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The C-roundabout (cyclist roundabout) is a new multi-lane roundabout designed to improve the safety of cyclists at and make multi-lane roundabouts more cyclist-friendly. The geometric layout of C-Roundabouts allows the decrease of the vehicle speeds through the roundabout to around 30 km/h. The rare C-roundabout installations so far implemented in the world have not allowed analysing the capacity by means empirical data. In the light of this considerations, the main objective of the paper is to give a theoretical closed-form model for evaluation the measures of effectiveness MOE (capacity, delay, queues) of the C-Roundabouts.
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Guerrieri, Marco, and Ferdinando Corriere. "Calculation of Turbo-Roundabouts with Slip Lanes." Applied Mechanics and Materials 459 (October 2013): 595–600. http://dx.doi.org/10.4028/www.scientific.net/amm.459.595.

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A turbo roundabout is a particular type of roundabout where all lanes are bounded by traffic signs and by non-mountable curbs installed at entering and circulating lanes. Turbo roundabouts also have a very particular shape to accomplish the splitting of traffic streams and to prevent cars weaving through. These aspects make turbo-roundabouts more appropriate than roundabouts when a higher level of safety has to be guaranteed, particularly in presence of relevant pedestrian and two-wheels traffic volumes. Only in some traffic conditions, turbo roundabouts can offer higher capacities than conventional double-lanes roundabouts, so if more capacity must be guarantee a bypass lane can be added to the turbo roundabouts layout. This paper presents a closed-form model for the estimation of capacity, delays and level of service of turbo-roundabout equipped with Right-turn bypass lanes, considering the effect of geometric slip lane schemes, control type, vehicular and pedestrian flow.
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Tollazzi, Tomaž, Goran Jovanović, and Marko Renčelj. "New Type of Roundabout: Dual One-Lane Roundabouts on Two Levels with Right-Hand Turning Bypasses – ’’Target Roundabout’’." PROMET - Traffic&Transportation 25, no. 5 (October 27, 2013): 475–81. http://dx.doi.org/10.7307/ptt.v25i5.1230.

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The problems of low level traffic safety on multi-lane roundabouts have been resolved in various ways in different countries, usually by using alternative types of roundabouts that reduce the number of conflict points. Alternative types of roundabouts typically differ from 'normal' or 'standard' roundabouts in one or more design elements, as their implementation purposes could also be specific. Today, several different types of roundabouts are already in use ('mini', 'double mini', 'dumb-bell', those 'with joint splitter islands' ('dog-bone'), those 'with a spiralling circular carriageway' ('turbo'), those 'with depressed lanes for right-hand turners' ('flower') etc.). This paper introduces a new type of roundabout, dual one-lane roundabouts on two levels with right-hand turning bypasses, namely the 'target roundabout'. This paper describes and analyses their design, traffic safety, and capacity characteristics, compared with the standard two–lane roundabouts.
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Macioszek, Elżbieta. "Roundabout Entry Capacity Calculation—A Case Study Based on Roundabouts in Tokyo, Japan, and Tokyo Surroundings." Sustainability 12, no. 4 (February 18, 2020): 1533. http://dx.doi.org/10.3390/su12041533.

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The article presents the calculation of roundabout entry capacity as a case study based on roundabouts located in Tokyo, Japan, and Tokyo surroundings. The analysis was conducted as part of the project entitled “Analysis of the applicability of the author’s method of roundabouts entry capacity calculation developed for the conditions prevailing in Poland to the conditions prevailing at roundabouts in Tokyo (Japan) and in the Tokyo surroundings”. The main aim and the research question was whether the author’s model of roundabouts entry capacity calculation constructed for the conditions prevailing in Poland after calibration is suitable to calculate roundabout entry capacity of roundabouts located in Tokyo and in the Tokyo surroundings. In order to perform the calibration in 2019, measurements were taken at the single-lane roundabouts located in Tokyo and Tokyo surroundings. The model calibration revealed that it is possible to evaluate the entry capacity of roundabouts located in Tokyo and in Tokyo surroundings using the author’s model.
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Ibanez, Guillermo, Tobias Meuser, Miguel A. Lopez-Carmona, and Diego Lopez-Pajares. "Synchronous Roundabouts with Rotating Priority Sectors (SYROPS): High Capacity and Safety for Conventional and Autonomous Vehicles." Electronics 9, no. 10 (October 20, 2020): 1726. http://dx.doi.org/10.3390/electronics9101726.

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Roundabouts are a highway engineering concept meant to reduce congestion and improve safety. However, experience shows that capacity of roundabouts is limited, and safety is not optimal. However, these improvements in capacity and safety should be compatible with both manually-driven and autonomous vehicles. Incorporating existing advanced technologies to the signaling and control of roundabouts will undoubtedly contribute to these improvements but should not restrict this compatibility. We approach roundabouts as synchronous switches of vehicles, and propose a roundabout system (synchronous roundabouts with rotating priorities) based on vehicle platoons arriving at the roundabout at a uniform speed and within the time slot assigned to their entry, avoiding conflicts and stops. The proposed signaling system is visual for human drivers and wireless for connected and autonomous vehicles. We evaluated analytically and with simulations roundabouts of different radii for several values of the average distance between vehicles. Results show that average delays are 28.7% lower, with negligible dispersion. The capacity improvements depend on design parameters, moderate for small roundabouts, but that goes up to 70–100% for short inter vehicular distances and medium and large roundabouts. Simulations with unbalanced traffic maintained the capacity improvement over standard roundabouts.
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Thai Van, May-Jeanne, and Pascal Balmefrezol. "Design of Roundabouts in France: Historical Context and State of the Art." Transportation Research Record: Journal of the Transportation Research Board 1737, no. 1 (January 2000): 92–97. http://dx.doi.org/10.3141/1737-12.

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First appearing in the French highway code in 1983, roundabouts have multiplied greatly throughout France, to the currently estimated 17,000. The success of roundabouts is explained, first, by the ideal safety conditions that this type of intersection presents and, second, by the advantages roundabouts provide in speed reduction, suitability to traffic, and break effect. The growth of roundabouts in recent years has allowed better understanding of this type of layout and has enabled all uses to be tested. The rules for designing and sizing have developed to favor the construction of roundabouts that are smaller and thus easier to fit into the urban environment. Vulnerable users (pedestrians and cyclists) are catered to better. New configurations are appearing that combine traffic lights and roundabouts, and these should be investigated in depth. Furthermore, it appears that the roundabout is subject to fashion and that many changes are planned to the roundabout—forgetting that it is not always the best solution. Also, it is important to remind designers and architects of the conditions under which the roundabout actually is an adequate solution for the site in question.
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Dissertations / Theses on the topic "Roundabouts"

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He, Yi. "Safety Effectiveness Analysis of Roundabouts in Louisiana." Thesis, University of Louisiana at Lafayette, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10683149.

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Louisiana currently has 30 roundabouts in operation and hundreds of roundabouts in the planning and design stage. The Louisiana Department of Transportation and Development (DOTD) is very interested in knowing the safety performance of existing roundabouts in the state.

As revealed in this paper, the safety effectiveness of a roundabout depends on its prior traffic control type, conformity to the geometric design guidelines, changes in layout of intersection, and nighttime lighting conditions. All 19 roundabouts investigated by this study demonstrated significant reduction in injury crashes because of lower operating speed, reduced right-angle collisions, and elimination of head-on and left turn crashes. Based on changes in the number of conflicting points and traffic control method, it is understandable why the most significant and consistent safety improvement was associated with the roundabouts previously controlled by stop signs on minor streets. The Crash Modification Factor (CMF), as estimated by the Empirical Bayes (EB) method, for this group of roundabouts is 0.28 with a standard deviation of 0.054. The roundabout is economically justified for its safety benefit alone based on the benefit-cost ratio analysis for this group of roundabouts.

The study did identify a few compounding factors at the individual intersections, such as questionable geometric design elements, increased number of conflicting points, unpredictable human behavior, and lack of lighting at night.

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Linse, Leif. "Capcal for small roundabouts : Current status and improvements." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-63822.

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Questions have been raised regarding how good Capcal works for roundabouts with a weaving length smaller than 25 meters and if Capcal would work for weaving lengths lower than the 16 meters that is the lower limit in the current model. In this thesis, two possible improvements has been developed and tested on five roundabouts with a weaving length less than 25 meters. Work has been done to build alternative gap acceptance models ranging from removal of the 16-meter limit through re-estimation of the current model to a completely new model. In this thesis a new sub model has been introduced that take into account the uncertainty of if circulating vehicles will exit or continue to circulate. These sub models have been combined in 29 different ways including the current Capcal model configuration and have been tested with five different roundabouts. The conflict delay, which is caused by interaction with other vehicles, has been used to compare the model results with delay observations from video captures of the roundabouts.   Out of all model configurations, the original Capcal 3.3 model had the lowest difference in average between the model result and the observations. If the 16-meter weaving length restriction in the original model is removed, almost the same results are obtained as with the restriction. While none of the model configurations improved the model fit, no configuration could be statistically be rejected. In the results of individual roundabouts, there were differences between the model and observations of up to 50%. This shows that while this thesis could not find any improvements of Capcal, there is a potential for future work to develop improvements of the roundabout model.
I nuläget tillåter Capcal att växlingssträckor ner till 16 meter modelleras, men i dataunderlaget som användes vid skapandet av nuvarande modell finns endast med en cirkulationsplats under 25 meter. Det har lyfts frågetecken kring huruvida Capcal ger bra resultat för cirkulationsplatser med en växlingssträcka på mindre än 25 meter samt huruvida modellens nedre gräns på 16 meter skulle kunna tas bort. I detta examensarbete har två olika möjligheter att förbättra modellen testats på fem olika cirkulationsplatser med växlingssträcka kortare än 25 meter. I arbetet har det ingått att ta fram alternativa gap-acceptance-modeller vilka sträcker sig från att enbart ta bort 16-metersgränsen via en nyestimering av Capcals modell till en helt ny modell. Därtill har en ny submodell skapats som tar hänsyn till den osäkerhet som uppstår kring huruvida cirkulerande fordon kommer att köra ur cirkulationen vid en utfart eller fortsätta cirkulera. De utvecklade submodellerna samt nuvarande Capcal modell har kombinerats i 29 olika kombinationer. Dessa 29 kombinationer har för varje av de fem studerade cirkulationsplatserna testats mot observationer från respektive cirkulationsplats. Konfliktfördröjningen, vilket är fördröjning på grund av interaktion med andra fordon, har använts för att jämföra Capcal-resultaten och observationerna.   Av alla modellkonfigurationer så gav nuvarande Capcal 3.3-modell lägst medelskillnad mellan modellresultat och observationer. Om 16-meter-restriktionen i nuvarande Capcal-modell tas bort, så fås i stort sett samma resultat. Ingen av de studerade modell-förändringarna gav en bättre passning mellan modell och verklighet i medel, men ingen förändring kunde förkastas ur statistisk synvinkel. Det var dock stora variationer i resultaten för enskilda cirkulationsplatser med upp till 50% skillnad mellan modellens resultat och observerade värden. Detta visar på att även om detta examensarbete inte lyckades hitta några förbättringar av Capcal, så finns det potential för framtida arbete att ta fram förbättringar av cirkulationsplatsmodellen i Capcal.
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Xu, Feng. "Driver behavior and gap acceptance studies at roundabouts." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1442865.

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Okezue, O. G. "Design and evaluation of signal controlled highway roundabouts." Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376698.

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Elbadrawi, Hesham Roshdy. "A computer simulation model for single-lane roundabouts." FIU Digital Commons, 2000. http://digitalcommons.fiu.edu/etd/3131.

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During the past three decades, the use of roundabouts has increased throughout the world due to their greater benefits in comparison with intersections controlled by traditional means. Roundabouts are often chosen because they are widely associated with low accident rates, lower construction and operating costs, and reasonable capacities and delay. In the planning and design of roundabouts, special attention should be given to the movement of pedestrians and bicycles. As a result, there are several guidelines for the design of pedestrian and bicycle treatments at roundabouts that increase the safety of both pedestrians and bicyclists at existing and proposed roundabout locations. Different design guidelines have differing criteria for handling pedestrians and bicyclists at roundabout locations. Although all of the investigated guidelines provide better safety (depending on the traffic conditions at a specific location), their effects on the performance of the roundabout have not been examined yet. Existing roundabout analysis software packages provide estimates of capacity and performance characteristics. This includes characteristics such as delay, queue lengths, stop rates, effects of heavy vehicles, crash frequencies, and geometric delays, as well as fuel consumption, pollutant emissions and operating costs for roundabouts. None of these software packages, however, are capable of determining the effects of various pedestrian crossing locations, nor the effect of different bicycle treatments on the performance of roundabouts. The objective of this research is to develop simulation models capable of determining the effect of various pedestrian and bicycle treatments at single-lane roundabouts. To achieve this, four models were developed. The first model simulates a single-lane roundabout without bicycle and pedestrian traffic. The second model simulates a single-lane roundabout with a pedestrian crossing and mixed flow bicyclists. The third model simulates a singlelane roundabout with a combined pedestrian and bicycle crossing, while the fourth model simulates a single-lane roundabout with a pedestrian crossing and a bicycle lane at the outer perimeter of the roundabout for the bicycles. Traffic data was collected at a modern roundabout in Boca Raton, Florida. The results of this effort show that installing a pedestrian crossing on the roundabout approach will have a negative impact on the entry flow, while the downstream approach will benefit from the newly created gaps by pedestrians. Also, it was concluded that a bicycle lane configuration is more beneficial for all users of the roundabout instead of the mixed flow or combined crossing. Installing the pedestrian crossing at one-car length is more beneficial for pedestrians than two- and three-car lengths. Finally, it was concluded that the effect of the pedestrian crossing on the vehicle queues diminishes as the distance between the crossing and the roundabout increases.
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Gbologah, Franklin E. "The impacts of illumination on nighttime safety at roundabouts." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54453.

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Roundabout installations are becoming common practice among DOTs and other local governments due to their superior safety attributes compared to other conventional at-grade intersections, especially stop-control and uncontrolled intersections. Current U.S. national guidelines for roundabout illumination recommend systematic illumination for all roundabouts. This recommendation might become a potential hindrance to desired widespread installations due to implied financial costs, especially in rural areas because the competing stop-control and uncontrolled intersections can be kept unlit. Interestingly rural roundabouts in most countries around the world are not illuminated as indicated by a recent survey of international roundabout illumination policies and standards from 45 countries. Also, review of intersection safety literature does not identify any publication that supports a systematic illumination policy of U.S. roundabouts. In fact, despite this recommendation there is no quantitative research on influence of illumination levels on nighttime safety at roundabouts and little on conventional intersections. Conversely, the literature shows a significant number of published studies which have indicated that currently recommended illumination levels on roadways can be reduced without compromising nighttime safety. This dissertation evaluates the link between roundabout crashes and different illumination levels. At the beginning of this dissertation research, there was no available repository of quantitative intersection illumination levels which could be used in highway safety research. Also, existing protocols for measurement require expensive light meters and are extremely time consuming to follow, making them impractical to use to study a large number of intersections. Consequently, this dissertation first evaluates the relationship with the best available data. The best available intersection illumination data was obtained from the Minnesota data contained in the Highway Safety Information System (HSIS). Minnesota crash and illumination data from 2003 to 2010 were analyzed. This illumination data was a qualitative description of intersection illuminating schemes and/or luminaire arrangement. Therefore, this dissertation also developed a cost-effective, accurate, and rapid method for measurement of quantitative intersection illumination data, and applied the developed protocol to a case study in Georgia. The measured intersection illumination was analyzed together with crash data obtained from GDOT for 2009 to 2014. The results of a naive analysis on the best available data indicated among other findings that the presence of lighting can provide approximately 61 percent lower total nighttime crash rate compared to the unlit condition. Also, providing illumination to the roundabout circle alone can yield about 80 percent of the benefits (55 percent reduction from unlit condition) of illuminating both the roundabout circle and approaches (66 percent reduction from unlit condition). Field test results for the camera calibration indicate that the average intersection illuminance derived from the protocol is within 4 percent difference of the actual average intersection illumination estimated from following the existing protocols. Next, despite limited roundabout data and potential issues of selection bias which could not be addressed in this dissertation, a cautious roundabout illumination specific crash modification factor was estimated with a negative binomial regression model. The model results showed that an increase of 1 lux in average roundabout illuminance will result in a 4.72 percent reduction in expected number nighttime crashes. The results of this work are useful in creating a sound framework for DOTs and other transportation agencies to determine the most appropriate level of illumination for roundabouts. This study also makes a number of significant contributions to highway safety research. First, this work is the first quantitative study on the impact of illumination on safety at roundabouts. The status-quo for highway safety research regarding the impacts of illumination had been to treat road lighting as a binary (Lit/Unlit) variable. However, even in most places without purposely-built road lighting there is usually ambient lighting from abutting facilities such as a gas stations or a store. Second, this dissertation is the first documented application of the photographic method to roundabouts. It is also the first documented application of the photographic method’s camera specific constant calibration approach to transportation field measurements. Previous documented application of the photographic method to transportation field measurements used an exposure specific calibration approach. Unlike the camera specific constant calibration approach, the exposure specific approach is rigid and field measurements must always be done at the exposure settings used in calibrating the camera. Thirdly, this work demonstrates the first developed procedure to developing uniformity (contour) plots from the photographic method. Next, this work can serve as the basis for initial efforts to create an illumination specific quantitative crash modification factor. Currently, the Highway Safety Manual is lacking in this important safety parameter. Last, but not the least this work offers procedures for collecting luminance data from the field and also documents a database of intersection illumination levels and intersection characteristics which can be used by future research.
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Toussant, Erica A. "Analyzing the Impacts of Driver Familiarity/Unfamiliarity at Roundabouts." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1451907184.

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Jackson, Meredith A. "Do Roundabouts Work? An Evaluation for Uniform Approach Demands." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76831.

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With the increased prevalence of roundabouts in the United States, there is a need to evaluate the performance of roundabouts relative to other intersection control strategies. Few studies have compared roundabouts with other intersection control strategies in a systematic fashion. Consequently, this Thesis compares four types of intersection control strategies considering a single lane approach with a 58 km/hr speed limit and equal demand on all approaches. The study demonstrates that vehicle delay is minimized with the use of a roundabout intersection control for all demand levels below 500 veh/hr/approach. Above this point if the left turn percentage exceeds 70% traffic signal control is more efficient. The roundabout alternative also produces the fewest vehicle stops for low demand levels, low left turn demand and high right turn demand, however a TWSC alternative produces the least number of vehicle stops when the through and total demand is high. This study illustrates that fuel consumption and carbon dioxide, carbon monoxide, hydrocarbon and nitrogen oxide emissions can be improved with roundabout control over other intersection control strategies. The research presented here demonstrates that for low traffic demand levels roundabouts should be part of design alternatives considered for isolated intersection control.
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Rescot, Robert Andrew. "Automating traffic studies at modern roundabouts a feasibility study /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5025.

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Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 12, 2009) Includes bibliographical references.
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Ren, Liang. "Development and Validation of New Capacity Models for Roundabouts." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/367372.

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There is increased interest in building modern roundabouts in Europe, Australia and North America because of the safety and operational benefits that can be realized from this type of intersection. With this interest comes the increasing need to be able to estimate the capacity, evaluate the performance and analyze the emission levels that a roundabout will be likely to provide once it is built. In the early 2000s, a National Cooperative Highway Research Program (NCHRP) study was conducted that, among other tasks, developed single-lane roundabout capacity estimation equations. These equations, presented in the Highway Capacity Manual 2000 and 2010 (referred to as HCM 2000 and 2010 hereafter), can be calibrated using locally determined values for the critical gap and follow-up time. Other models, such as the German Highway Capacity Manual (referred to as GHCM) and SR45 models are also widely used in estimating capacity around the world. However, some studies have indicated that the existing models could under or overestimate roundabout capacity because some important factors, such as headway distribution type, proportion of exiting vehicles and heavy goods vehicles, are not taken into account.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Books on the topic "Roundabouts"

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Roundabouts. Washington, D.C.]: U.S. Dept. of Transportation, Federal Highway Administration, Office of Safety, 2010.

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Züst, Andreas. Roundabouts. Zürich: Edition Patrick Frey c/o Scalo, 2004.

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McKenna, Jonathan. Magic roundabouts. Dublin: University College Dublin, 2001.

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McKenna, Jonathan. Magic roundabouts. Dublin: University College Dublin, 2001.

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Mini-roundabouts. Washington, D.C.]: U.S. Dept. of Transportation, Federal Highway Administration, Office of Safety, 2010.

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Bouwmeester, Belgium Vlaams. Roundabouts: Traffic roundabouts as a context for art. Brussel: Mercatorfonds, 2007.

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Glass, Harry. Swings and roundabouts. Glasgow: Pedersen Press, 1992.

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Swings and roundabouts. Bath: Chivers, 1987.

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Mauro, Raffaele. Calculation of Roundabouts. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-04551-6.

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Eldon, John. Swings and roundabouts. Minchinhampton: Besbury, 1996.

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Book chapters on the topic "Roundabouts"

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Tollazzi, Tomaž. "Origins of Roundabouts." In Alternative Types of Roundabouts, 1–9. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09084-9_1.

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Tollazzi, Tomaž. "Modern Roundabouts Design." In Alternative Types of Roundabouts, 57–116. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09084-9_3.

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Gulyás, András, Zalán Heszberger, and József Biró. "Everybody Loves Roundabouts." In Paths, 5–10. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47545-1_2.

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Simon, Michel J. "Roundabouts in Switzerland." In Intersections without Traffic Signals II, 41–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-84537-6_4.

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Prassas, Elena S., and Roger P. Roess. "Unsignalized Intersections: Roundabouts." In Springer Tracts on Transportation and Traffic, 125–36. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34480-1_6.

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Chown, Alison, and Penny McFarlane. "Swings or roundabouts?" In Routledge International Handbook of Play, Therapeutic Play and Play Therapy, 289–300. Milton Park, Abingdon, Oxon ; New York, NY : Routledge, 2021. | Series: Routledge international handbooks: Routledge, 2020. http://dx.doi.org/10.4324/9780429327230-31.

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Mauro, Raffaele. "Calculation of Roundabouts: Problem Definition." In Calculation of Roundabouts, 1–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04551-6_1.

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Mauro, Raffaele. "Capacity Evaluation." In Calculation of Roundabouts, 15–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04551-6_2.

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Mauro, Raffaele. "Waiting Phenomena at Steady State and Non-steady State Conditions." In Calculation of Roundabouts, 59–105. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04551-6_3.

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Mauro, Raffaele. "Calculation of Waiting Times, Queue Lengths, and Levels of Service." In Calculation of Roundabouts, 107–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04551-6_4.

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Conference papers on the topic "Roundabouts"

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Ahac, Saša, and Petra Kipa. "Investigation of the clear sight areas on suburban roundabouts." In 7th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2022. http://dx.doi.org/10.5592/co/cetra.2022.1348.

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To achieve safe and unobstructed traffic flow at roundabouts and their approaches, the important condition that needs to be met is adequate visibility. Namely, a clear line of sight must be ensured to enable a driver without the right of way to engage in the roundabout traffic flow safely and to note on time the position of the vehicle in front of him. The issue of sight distance evaluation on suburban single-lane roundabouts will be analysed in this paper. A critical review of several roundabout design standards and guidelines (Australian, Croatian, and Italian) that describe procedures for determining the necessary sight distance at these intersections will be given. Influential parameters for defining clear sight areas will be presented in detail, with an emphasis on the diversity of roundabout sight distance evaluation approaches. Key issues of the existing Croatian guidelines will be identified, and recommendations for the improvement will be given. Test results obtained on a theoretical example of a suburban roundabout will also be commented on.
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Klobučar, Mirna, Aleksandra Deluka-Tibljaš, Sanja Šurdonja, Tiziana Campisi, and Robert Maršanić. "Roundabout approaching speed analyses." In 7th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2022. http://dx.doi.org/10.5592/co/cetra.2022.1444.

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Roundabouts are very often implemented as a measure for speed control at the intersections where there is a problem with traffic safety. Although the approaching speed is emphasized in some research as relevant for operational speed in the roundabout, there are no detailed analyses of the effects of geometric and traffic elements on approaching speed that can be used to design safer roundabouts. The experimental study presented in this paper was done on six different roundabouts, on 22 approaches, located at a regional road network. The outer radii of analyzed roundabouts were from 15 to 22 m. The speed was measured for 24 hours at every approach. As operational speed, v85 - speed up to which 85% of vehicles are moving was included in the analyses. The impact of main geometric elements – lane width, slope, and length of the straight part of the road before entrance to the roundabout was analyzed. As a traffic parameter, the impact of the posted speed limit at the approach on the operational speed was also analyzed. Some preliminary recommendations regarding speed control were generated as a conclusion of this study.
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Hannun, Jameel, Jamal Hannun, Khaled Shamiyeh, Mohammad Ghanim, and Mohamed Kharbeche. "Operational Performance and Safety Assessment of Signalized Roundabouts." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0077.

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Roundabouts are widely used to reduce the severity of conflicts at intersecting roads. While they tend to provide an acceptable level of traffic operation, their operational benefits are reduced when traffic demands increase. One possible and economic mitigation is to convert the roundabouts into signalized ones to accommodate the demand increase and to further reduce the conflicts. This conversion will allow the roundabouts to perform both functions (safety and operational) within acceptable levels. Accordingly, proper signal timing parameters are often required to achieve the anticipated safety and operational levels. Unlike the operational performance of signalized intersections that can be easily assessed based on field measurements, safety assessment is far more difficult due to the need of historical crash data, which would potentially take years. This study presents the use of traffic simulation to assess the operational performance as well as the safety performance of signalized intersections. At first, a well-calibrated model of a signalized roundabout located in the city of Doha is built in microscopic traffic simulation environment based on field measurements and observations. Secondly, Surrogate Safety Assessment Method (SSAM) is used to analyze the simulated vehicular trajectories to identify the type and severity of conflicts. The results revealed that the implemented signal timing parameters have a significant impact on the safety functionality of the signalized roundabouts.
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Sides, Ken, and Gene Russell. "Roundabouts and Carbon Management." In Carbon Management Technology Conference. Carbon Management Technology Conference, 2012. http://dx.doi.org/10.7122/151264-ms.

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De Winne, E. "Roundabouts for safer roads." In SAFE 2009. Southampton, UK: WIT Press, 2009. http://dx.doi.org/10.2495/safe090501.

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Ariniello, Alex, and Bart Przybyl. "Roundabouts and Sustainable Design." In Green Streets and Highways Conference 2010. Reston, VA: American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41148(389)8.

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Bey, Henrik, Moritz Sackmann, Alexander Lange, and Jorn Thielecke. "POMDP Planning at Roundabouts." In 2021 IEEE Intelligent Vehicles Symposium Workshops (IV Workshops). IEEE, 2021. http://dx.doi.org/10.1109/ivworkshops54471.2021.9669232.

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Raimundo, Vazquez, and Mason Favio. "Driver intention prediction at roundabouts." In 2021 XIX Workshop on Information Processing and Control (RPIC). IEEE, 2021. http://dx.doi.org/10.1109/rpic53795.2021.9648491.

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Liu, Runfen. "Roundabouts Improve the Safety of Intersections." In 2017 International Conference on Humanities Science, Management and Education Technology (HSMET 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/hsmet-17.2017.172.

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Mahdalova, Ivana. "DISORDERS OF STRUCTURE ELEMENTS ON ROUNDABOUTS." In 15th International Multidisciplinary Scientific GeoConference SGEM2015. Stef92 Technology, 2015. http://dx.doi.org/10.5593/sgem2015/b62/s26.012.

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Reports on the topic "Roundabouts"

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Day, Christopher, Alexander Hainen, and Darcy Bullock. Best Practices for Roundabouts on State Highways. Purdue University, December 2013. http://dx.doi.org/10.5703/1288284315216.

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Adsit, Sarah E., Theodora Konstantinou, Konstantina Gkritza, and Jon D. Fricker. Public Acceptance of INDOT’s Traffic Engineering Treatments and Services. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317280.

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As a public agency, interacting with and understanding the public’s perspective regarding agency activities is an important endeavor for the Indiana Department of Transportation (INDOT). Although INDOT conducts a biennial customer satisfaction survey, it is occasionally necessary to capture public perception regarding more specific aspects of INDOT’s activities. In particular, INDOT needs an effective way to measure and track public opinions and awareness or understanding of a select set of its traffic engineering practices. To evaluate public acceptance of specific INDOT traffic engineering activities, a survey consisting of 1.000 adults residing within the State of Indiana was conducted. The survey population was representative in terms of age and gender of the state as of the 2010 U.S. Census. The survey was administered during the months of July and August 2020. Public awareness regarding emerging treatments not currently implemented in Indiana is low and opposition to the same new technologies is prominent. Older or female drivers are less likely to be aware of emerging treatments, and older drivers are more likely to oppose potential implementation of these treatments. Although roundabouts are commonplace in Indiana, multi-lane roundabouts remain controversial among the public. Regarding maintenance and protection of traffic during work zones and considering full or partial roadway closure, public preference is for partial closure; this preference is stronger in rural areas. The public equally agrees and disagrees that INDOT minimizes construction related traffic delays. Approximately 76% of Indiana drivers believe themselves to above average drivers, while an additional 23% believe themselves to be average. Driver perceptions of average highway speeds speed are not aligned with posted speed limit as the perceived average speed on Indiana’s urban freeways and rural and urban state highways is considerably higher than the actual speed limit.
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Cohen, Yves. Horizontality in the 2010s: Social Movements, Collective Activities, Social Fabric, and Conviviality. Maria Sibylla Merian Centre Conviviality-Inequality in Latin America, October 2021. http://dx.doi.org/10.46877/cohen.2021.40.

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Horizontality is a salient social phenomenon of the last decade. It asserts itself against hierarchies in social movements and countless other collective practices around the world. It constitutes a characteristic of an emergent sociality that demands the attention of the social sciences. The 2010s are a moment as important as “the Sixties”, a time when Ivan Illich called for the development of tools of conviviality, and horizontality may be categorized as one of them. Today’s horizontality may be related to that of populations that have been the focus of anthropologists interested in their longstanding propensity to work against the affirmation of the authority of commanding. Public squares, roundabouts, and the courtyards of apartment buildings welcome the early symptoms of democratic experimentation that circulates also among groups, collectivities, and associations with varied purposes. In all these places, equality asserts itself and cuts across differences. The Yellow Vests and an educational cooperative in São Paulo are the empirical foundation of this study.
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Bullock, Christine, Mary Chastenet de Gery, and Jamie Gerard. MARSAME Radiological Release Report for Diamond Drive Widening and Roundabout Construction Projects. Office of Scientific and Technical Information (OSTI), October 2022. http://dx.doi.org/10.2172/1893636.

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Tarko, Andrew, Mario Romero, Thomas Hall, Shaikh Ahmad Matin, and Cristhian Lizarazo. Evaluation of Alternative Intersections and Interchanges: Volume I—Roundabout Capacity and Rollover Analysis for Heavy Vehicles. Purdue University, December 2015. http://dx.doi.org/10.5703/1288284316011.

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Roundabouts with Cycling Traffic. Deutsches Institut für Urbanistik (Difu), 2013. http://dx.doi.org/10.26128/2023.18.

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