Central European Comparative Study of Traffic Safety on Roundabouts

Ambros, Jiří; Novák, Jan; Borsos, Attila; Hóz, Erzsébet; Kieć, Mariusz; Machciník, Štefan; Ondrejka, Roman

doi:10.1016/j.trpro.2016.05.391

Cited by 18 publications

(17 citation statements)

References 12 publications

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“…Reviews done on the basis of data from 28 studies from different countries [1] show that roundabouts are associated with a reduction of 30 to 50% in the number of injury accidents and that fatal accidents are reduced by 50 to 70%. The results based on available accident data were similar, of studies on roundabouts traffic safety done for middle European countries [2] and also those done by Rodegerdts et al [3] for different countries around the world.…”

Section: Introductionsupporting

confidence: 83%

Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation

et al. 2018

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Driving experiences provided by the introduction of new vehicle technologies are directly impacting the criteria for road network design. New criteria should be taken into consideration by designers, researchers and car owners in order to assure traffic safety in changed conditions that will appear with, for example, introduction of Autonomous Vehicles (AVs) in everyday traffic. In this paper, roundabout safety level is analysed on the originally developed microsimulation model in circumstances where different numbers of AVs vehicles are mixed with Conventional Vehicles (CVs). Field data about speed and traffic volumes from existing roundabouts in Croatia were used for development of the model. The simulations done with the Surrogate Safety Assessment Model (SSAM) give some relevant highlights on how the introduction of AVs could change both operational and safety parameters at roundabouts. To further explore the effects on safety of roundabouts with the introduction of different shares of AVs, hypothetical safety treatments could be tested to explore whether their effects may change, leading to the estimation of a new set of Crash Modification Factors.

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Section: Introductionsupporting

confidence: 83%

Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation

et al. 2018

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“…The trend is rising from E1 (single entry and circulatory lane) to E3 (two entry and circulatory lanes). Positive association between entry width (number of lanes) and crash frequency was identified in several studies (9,19,37,44,45).…”

Section: Signs Of Regression Coefficients B I Enable the Interpretation Of Directions Of Influence Of Individual Variables On Response Vamentioning

confidence: 83%

How Roundabout Entry Design Parameters Influence Safety

Novák

Ambros

Frič

2018

Transportation Research Record: Journal of the Transportation R

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Roundabouts are considered the safest intersection design; however, the safety effect may not be satisfactory at each specific roundabout. This is true especially in countries where roundabout design is a relatively new concept, such as in the Czech Republic. Specifically, most Czech roundabout crashes were found to occur on entries. This motivated the presented study to investigate how entry design parameters influence safety on Czech roundabouts and, if possible, use the findings to update current Czech roundabout design guidelines. To this end, the study comprised three analyses: crash-based safety performance functions, speed analysis, and finally safety performance functions which incorporated speed. All three analyses proved that entry design parameters have a statistically significant influence on safety, in terms of crash frequency, severity and speeds. Given the study objective, this fact should be considered in Czech roundabout design guidelines.

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“…For intersections on national roads, traffic control device and presence/absence of turn lanes and bypass lanes was recorded. Following previous Czech studies [3,77], roundabouts were further described by number of legs, inscribed circle diameter, central island diameter, average of roundabout entry angles, average of deviation angles, width of circulatory lane, and width of truck apron. Sections of national roads were described by length and curvature change rate (CCR).…”

Section: Road Datamentioning

confidence: 99%

Safety assessment of Czech motorways and national roads

Ambros

Turek

Brich

et al. 2019

Eur. Transp. Res. Rev.

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Purpose: Czech motorways and national roads form the primary road network, which is critical in terms of safety. To be able to rationally manage network safety in both planning and operation stages, quality network-wide data and tools are needed. While such tools already exist in some countries, their transferability is limited. Authors therefore collected data and used it to develop tools, which allowed conducting state-of-the-art road safety impact assessment and network safety ranking in the Czech conditions. In addition to primary road network, focus was widened to include also secondary roads, in order to enable assessment of impacts on adjacent road network. Methods: Accident, road and traffic data was collected, using not only existing databases, but also including own collection of traffic volumes on motorway interchanges. Data was used to develop the tools, based on accident prediction models and accident modification factors. Results: The final accident prediction models and accident modification factors enabled conducting road safety impact assessment, for which simple on-line tool was also developed. For network safety ranking, accident prediction models were applied according to the Empirical Bayes method, in order to determine potential for safety improvement of the studied road network elements, with the final priority list visualized in an on-line map. Both outputs are shortly presented in the paper. Conclusions: Data and sample size limitations lead to some compromises in modelling, such as using fixed proportions of observed accident severities or omitted variables. Nevertheless, the study established the practical framework for both road safety impact assessment and network safety ranking. It may serve as an example for other member countries, which also lack their local tools. Follow-up studies may focus on future model updating and improvements, as well as development of local accident modification factors.

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Central European Comparative Study of Traffic Safety on Roundabouts

Cited by 18 publications

References 12 publications

Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation

Introduction of Autonomous Vehicles: Roundabouts Design and Safety Performance Evaluation

How Roundabout Entry Design Parameters Influence Safety

Safety assessment of Czech motorways and national roads

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