Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode

Turbo roundabouts are a particular road intersection layout, designed to increase the safety of double-lane roundabouts, while maintaining their excellent capacity. The main feature of this new concept of roundabout is the impossibility to move from one lane to another, provided by physical barriers...

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Main Authors: Raffaele Mauro, Marco Cattani, Marco Guerrieri
Format: Article
Language:English
Published: Riga Technical University Press 2015-03-01
Series:The Baltic Journal of Road and Bridge Engineering
Subjects:
Online Access:https://bjrbe-journals.rtu.lv/article/view/3414
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author Raffaele Mauro
Marco Cattani
Marco Guerrieri
author_facet Raffaele Mauro
Marco Cattani
Marco Guerrieri
author_sort Raffaele Mauro
collection DOAJ
description Turbo roundabouts are a particular road intersection layout, designed to increase the safety of double-lane roundabouts, while maintaining their excellent capacity. The main feature of this new concept of roundabout is the impossibility to move from one lane to another, provided by physical barriers marking the lanes. The paper shows an application to turbo roundabouts of a potential accident rate model, aiming to evaluate their safety improvement. The model is based on the concept of potential conflict: each vehicle involved in a general intersection performs a series of maneuvers which potentially imply a crash, according to the actual traffic. The number of accidents related to each critical maneuver is proportional to the number of times this maneuver occurs at the intersection. In order to define the critical maneuvers, and hence the relevant potential conflicts, specific crash typologies for roundabouts are adopted. Traffic volumes are required, to evaluate the expected number of accidents, and also probabilities of accident for every critical maneuver. These ratios were obtained by a model calibration, based on actual accident and traffic data recorded on conventional single and double-lane roundabouts. The model was then used to compare four-leg turbo roundabouts to conventional roundabouts. The comparisons have taken into account only basic differences in layout, such as geometric elements, that also play a role in determining safety performances of a roundabout. The results obtained show that turbo roundabouts significantly decrease the accident rate with respect to conventional roundabouts, by eliminating conflicts between circulating and exiting vehicles.
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spelling doaj-art-6337033b6f704a57b9764ce955bdce692025-01-02T16:10:30ZengRiga Technical University PressThe Baltic Journal of Road and Bridge Engineering1822-427X1822-42882015-03-01101283810.3846/bjrbe.2015.041860Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate ModeRaffaele Mauro0Marco Cattani1Marco Guerrieri2Dept of Civil, Environmental and Mechanical Engineering, University of Trento, via Mesiano, 77–38123 Trento, ItalyCivil Engineer, Director of Trentino Mobilità s.p.a., via Brennero, 98‒38122 Trento, ItalyPolytechnic School of the University of Palermo, viale delle Scienze, Ed. 9–90128 Palermo, ItalyTurbo roundabouts are a particular road intersection layout, designed to increase the safety of double-lane roundabouts, while maintaining their excellent capacity. The main feature of this new concept of roundabout is the impossibility to move from one lane to another, provided by physical barriers marking the lanes. The paper shows an application to turbo roundabouts of a potential accident rate model, aiming to evaluate their safety improvement. The model is based on the concept of potential conflict: each vehicle involved in a general intersection performs a series of maneuvers which potentially imply a crash, according to the actual traffic. The number of accidents related to each critical maneuver is proportional to the number of times this maneuver occurs at the intersection. In order to define the critical maneuvers, and hence the relevant potential conflicts, specific crash typologies for roundabouts are adopted. Traffic volumes are required, to evaluate the expected number of accidents, and also probabilities of accident for every critical maneuver. These ratios were obtained by a model calibration, based on actual accident and traffic data recorded on conventional single and double-lane roundabouts. The model was then used to compare four-leg turbo roundabouts to conventional roundabouts. The comparisons have taken into account only basic differences in layout, such as geometric elements, that also play a role in determining safety performances of a roundabout. The results obtained show that turbo roundabouts significantly decrease the accident rate with respect to conventional roundabouts, by eliminating conflicts between circulating and exiting vehicles.https://bjrbe-journals.rtu.lv/article/view/3414turbo roundaboutsdouble-lane roundaboutpotential conflictspotential accident rate model
spellingShingle Raffaele Mauro
Marco Cattani
Marco Guerrieri
Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
The Baltic Journal of Road and Bridge Engineering
turbo roundabouts
double-lane roundabout
potential conflicts
potential accident rate model
title Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
title_full Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
title_fullStr Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
title_full_unstemmed Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
title_short Evaluation of the Safety Performance of Turbo Roundabouts by Means of a Potential Accident Rate Mode
title_sort evaluation of the safety performance of turbo roundabouts by means of a potential accident rate mode
topic turbo roundabouts
double-lane roundabout
potential conflicts
potential accident rate model
url https://bjrbe-journals.rtu.lv/article/view/3414
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AT marcocattani evaluationofthesafetyperformanceofturboroundaboutsbymeansofapotentialaccidentratemode
AT marcoguerrieri evaluationofthesafetyperformanceofturboroundaboutsbymeansofapotentialaccidentratemode