Speed Impacts from Roundabouts and Other Traffic Control Devices
Roundabouts are widely acknowledged to be very effective at reducing drivers’ speeds. These lower speeds are one of the reasons why roundabouts tend to experience significantly fewer injuries and fatalities as compared to other types of intersection control. Roundabouts are also a promising speed control measure, particularly on corridors with high volumes of pedestrian and bicycle traffic. However, the specific impacts on speeds are found to vary across locations due to geometric differences, the presence of supplementary traffic control devices, and other factors. Furthermore, it is unclear the degree to which speeds vary on the entry and exit approaches as compared to other types of intersections. This provides motivation for research to compare entry and exit speeds between roundabouts and intersections with alternative types of traffic control. This information would help to improve geometric design and provide metrics that are useful for intersection control evaluation reports, as well as in aligning target speeds, design speeds, and operating speeds as part of a Safe Systems approach to road design. A better understanding of the impacts on speed selection may also serve to address public concerns that often arise with the introduction of roundabouts. This information may also allow for more accurate estimates of other performance measures, including capacity and delay. To that end, this research proposes to examine how various speed metrics differ between roundabouts and intersections with other forms of traffic control. Field data will be collected to examine vehicle speeds upstream, downstream, and at the intersection entries and exits. The results of this study will provide critical insight and guidance for forecasting the operational and safety implications of various design decisions.
Language
- English
Project
- Status: Active
- Funding: $149002
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Contract Numbers:
1036336 WO 14
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Sponsor Organizations:
Minnesota Department of Transportation
395 John Ireland Boulevard
St Paul, MN United States 55155 -
Managing Organizations:
Minnesota Department of Transportation
395 John Ireland Boulevard
St Paul, MN United States 55155 -
Performing Organizations:
Michigan State University, East Lansing
Department of Civil & Environmental Engineering
Institute for Community Development
East Lansing, MI United States 48824-1226 -
Principal Investigators:
Savolainen, Peter
Dey, Kakan
Gates, Tim
- Start Date: 20240805
- Expected Completion Date: 20260630
- Actual Completion Date: 0
Subject/Index Terms
- TRT Terms: Alternatives analysis; Geometric design; Intersections; Metrics (Quantitative assessment); Operating speed; Roundabouts; Traffic speed
- Subject Areas: Design; Highways; Operations and Traffic Management;
Filing Info
- Accession Number: 01926598
- Record Type: Research project
- Source Agency: Minnesota Department of Transportation
- Contract Numbers: 1036336 WO 14
- Files: RIP, STATEDOT
- Created Date: Aug 7 2024 9:25AM