Comparison of Safety Performance Models for Urban Roundabouts in Italy and Other Countries
In Italy, almost half of all road crashes occur at intersections, primarily in urban areas. In recent years the widespread conversion of at-grade intersections to roundabouts has brought many safety advantages. To assess the safety benefits of roundabouts, transportation professionals need the powerful statistical tool known as the safety performance function (SPF). To date there has been no reported application of this tool to assess the relative safety performance of Italian urban roundabouts. This paper fills that void by using data sets from two municipalities in northern Italy. SPFs were estimated for each city with the negative binomial error distribution and then recalibrated for application in the other city by using the procedure described in the "Highway Safety Manual." Model reliability and between-city transferability were evaluated with the cumulative residuals method. To assess how the Italian roundabout SPFs might be used to learn lessons from differences in crash experience for similar intersections elsewhere, a comparison with models from other countries is also provided. This comparison reveals that Italian roundabouts tend to be less safe. Potential reasons for this finding are explored.
- Record URL:
- Summary URL:
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Availability:
- Find a library where document is available. Order URL: http://www.trb.org/Main/Blurbs/166819.aspx
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Authors:
- Sacchi, Emanuele
- Bassani, Marco
- Persaud, Bhagwant
- Publication Date: 2011
Language
- English
Media Info
- Media Type: Print
- Features: Figures; References; Tables;
- Pagination: pp 23-259
- Monograph Title: Highway and Traffic Safety: Vehicles, Behavior, and Roundabouts
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Serial:
- Transportation Research Record: Journal of the Transportation Research Board
- Issue Number: 2265
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Crash data; Highway safety; Mathematical models; Roundabouts; Traffic crashes; Urban areas
- Identifier Terms: Safety Performance Functions
- Uncontrolled Terms: Transferability of models
- Geographic Terms: Italy; Novara (Italy); Trento (Italy)
- Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I82: Accidents and Transport Infrastructure;
Filing Info
- Accession Number: 01333517
- Record Type: Publication
- ISBN: 9780309223027
- Report/Paper Numbers: 11-2538
- Files: TRIS, TRB
- Created Date: Mar 21 2011 2:14PM