module 3 safety considerations safety benefits of roundabouts roundabouts in the united states...
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Module 3
Safety Considerations
Safety benefits of roundabouts
Roundabouts in the United States
Research has shown there are many safety benefits associated with roundabout intersection design.
Roundabouts in the United States Module 3—Safety Considerations
Safety is a major consideration on our highways and roadways
In the year 2003 there were an average of 6,850 motor vehicle crashes per day at intersections in the United States.
For transportation professionals, safety is a major concern.
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Roundabouts in the United States Module 3—Safety Considerations
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Intersections are the scene of many accidents.
Transportation professionals are always looking for ways to reduce the number and severity of crashes.
Roundabouts in the United States Module 3—Safety Considerations
What is the effect on crash rates after an intersection is converted to a roundabout?
Conventional 4-way Intersection
Roundabout
Data from 55 intersections with at least 2 years of crash data before and after conversion of the intersection to a roundabout.
1122
726
Roundabouts in the United States Module 3—Safety Considerations
RoundaboutConventional 4-way Intersection
What is the effect on severe injury rates after an intersection is converted to a roundabout?
Data from 55 intersections with at least 2 years of crash data before and after conversion of the intersection to a roundabout.
72
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Roundabouts in the United States Module 3—Safety Considerations
Urban Signalized Intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts?
3514
Roundabouts in the United States Module 3—Safety Considerations
Suburban Signalized Intersection
Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts?
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98
Roundabouts in the United States Module 3—Safety Considerations
How do typical types of crashes compare between conventional intersections and roundabouts?
AWSC intersection Roundabout
13 17
Roundabouts in the United States Module 3—Safety Considerations
Rural TWSC intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts?
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71
Roundabouts in the United States Module 3—Safety Considerations
Suburban TWSC intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts?
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Roundabouts in the United States Module 3—Safety Considerations
RoundaboutUrban TWSC intersection
How do typical types of crashes compare between conventional intersections and roundabouts?
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Roundabouts in the United States Module 3—Safety Considerations
Typical types of crashes at roundabouts
Entering
Roundabouts in the United States Module 3—Safety Considerations
Typical types of crashes at roundabouts
Exiting
Roundabouts in the United States Module 3—Safety Considerations
Typical types of crashes at roundabouts
Examples of Loss of Vehicle Control
Roundabouts in the United States Module 3—Safety Considerations
Typical types of crashes at roundabouts
-76%-35%
-87%-72%-71%-32%-81%-29%
-60%TOO FE W
-67% TOO FE W
S IMIL A R S IMIL A R
Roundabouts in the United States Module 3—Safety Considerations
Bicycle and Pedestrian Considerations
Intersections also introduce concerns for transportation professionals on the safest way to accommodate pedestrians and cyclists.
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Roundabouts in the United States Module 3—Safety Considerations
Pedestrian Considerations at Roundabouts
Data on pedestrian/motor vehicle crashes is very limited.P
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Roundabouts in the United States Module 3—Safety Considerations
How do typical types of pedestrian/motor vehicle crashes compare between conventional intersections and roundabouts?
Motor vehicles conflict with pedestrians in the crosswalk areas and can occur as the vehicles enter or leave the intersection from several different directions.
A roundabout allows a pedestrian to observe motor vehicles from one direction at a time as they cross the travel lanes.
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Roundabouts in the United States Module 3—Safety Considerations
Pedestrian Considerations at Roundabouts
“Personally, I love them, . . . you only have to stop one lane of traffic, then go to the middle and wait. The cars can’t go much faster than 20 mph through the roundabout so the crossing aspect is great”
From the Howard-Suamico—Denise Haltom, School Crossing Guard, Suamico, Wisconsin
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Roundabouts in the United States Module 3—Safety Considerations
Bicycle Considerations
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Roundabouts in the United States Module 3—Safety Considerations
Cyclist Movements at Roundabouts – Circulating as a Vehicle.
Bikes merge with motor vehicles
Bikes re-enter bike lane
Bike lanes are not recommended within a roundabout. Instead, cyclists merge with traffic before entering the roundabout, circulate with traffic, and then re-enter the bike lane after exiting.
Lower motor vehicle speeds (15-20 mph)
Fewer conflict points with motor vehicles
Roundabouts in the United States Module 3—Safety Considerations
Cyclist Movements at Roundabouts – Circulating as a Pedestrian.
If a cyclist is uncomfortable riding with traffic, a cyclist can choose to travel instead as a pedestrian.
Bikes join shared path with pedestrians
Bikes return to bike lane
Bicyclists cross as pedestrians
Roundabouts in the United States Module 3—Safety Considerations
Summary of the Safety Features of Roundabouts
• Travel speeds generally reduced by traffic calming effects
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• In almost all cases, the total number of crashes is reduced when a conventional intersection is replaced with a roundabout
• And more importantly, the number of severe injury crashes is dramatically reduced due to the roundabout’s common direction of travel and similar speeds