01372495

Component

https://doi.org/10.3141/2312-01

http://scholar.google.com...mark&publication_year=2012

Roundabouts have proved to be effective in urban and suburban environments in the United States, but little has been reported on the effectiveness of roundabouts in rural environments on high-speed roadways. There is no question that roundabouts reduce the speeds of all vehicles at intersections and reduce the frequency of fatal and injury-related crashes. This research is the first comprehensive look at roundabouts in a rural environment with high-speed approaches. Nineteen intersections had ample comprehensive crash data to be evaluated and analyzed for safety performance. The findings validated the hypothesis that roundabouts in a rural environment as well as roundabouts in urban and suburban environments outperformed other intersection safety improvements. A before-and-after crash analysis was conducted for the 19 intersections by using a negative binomial regression model. Results showed statistically significant reductions for the total number of crashes (63%) and injury crashes (88%) when roundabouts were implemented. A before-and-after empirical Bayes estimation was also conducted, and the results were consistent, indicating a 62% to 67% reduction in total crashes and an 85% to 87% reduction in injury crashes at these rural intersections. Furthermore, results showed that injury-producing crash types, such as the angle crash, were reduced by 91%, and were statistically significant. Finally, this research produced crash prediction models at planning level for total and injury crashes at rural roundabouts on high-speed roadways. This supplements the models produced in NCHRP Report 572: "Roundabouts in the United States" and reported in the AASHTO "Highway Safety Manual."

01470175

12-4191

English

pp 3–13

2012

Transportation Research Record: Journal of the Transportation Research Board

9780309263108

Print

Figures; References; Tables

Before and after studies; Crash analysis; Crash injuries; Highway safety; Roundabouts; Rural areas; Traffic crashes

Crash prediction models; High speed roads

Design; Highways; Operations and Traffic Management; Safety and Human Factors; I82: Accidents and Transport Infrastructure

TRIS, TRB, ATRI

Feb 8 2012 5:22PM

• Analytical Method for Estimating Delays to Vehicles Traversing Single-Lane Roundabouts as a Function of Vehicle and Pedestrian Volumes
• Bus Contraflow Lane: Improved Contraflow Approach in Freeway Evacuation
• Changes in Evacuation Decisions Between Hurricanes Ivan and Katrina
• Comparison of Time-Dependent Sequential Logit and Nested Logit for Modeling Hurricane Evacuation Demand
• Delay Analysis of Single-Lane Roundabout with a Slip Lane Under Varying Exit Types, Experimental Balanced Traffic Volumes, and Pedestrians, Using Microsimulation
• Dynamic Traffic Assignment Evaluation of Hurricane Evacuation Strategies for the Houston–Galveston, Texas, Region
• Effect of Pedestrian Impedance on Vehicular Capacity at Multilane Roundabouts with Consideration of Crossing Treatments
• Empirical Estimation of Capacity for Roundabouts Using Adjusted Gap-Acceptance Parameters for Trucks
• Evacuee Route Choice Decisions in a Dynamic Hurricane Evacuation Context
• Examining Statewide Public Perceptions of Roundabouts Through a Web-Based Survey
• Modeling Risk Attitudes in Evacuation Departure Choices
• Optimization of Vehicle Travel Position on Roundabouts in Snowy Cold Regions
• Simulator Study of Driver Responses to Pedestrian Treatments at Multilane Roundabouts
• Travel Time Reliability During Evacuation: Impact of Heterogeneous Driving Behavior
• Turning Angle Effect on Emergency Egress: Experimental Evidence and Pedestrian Crowd Simulation
• Use of Regional Transportation Planning Tool for Modeling Emergency Evacuation: Case Study of Northern New Jersey