230 likes | 396 Views
Roundabouts in the United States. Module 3 Safety Considerations . Safety benefits of roundabouts . Research has shown there are many safety benefits associated with roundabout intersection design. Safety is a major consideration on our highways and roadways.
E N D
Roundabouts in the United States Module 3Safety Considerations Safety benefits of roundabouts Research has shown there are many safety benefits associated with roundabout intersection design.
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. PHOTOGRAPHY SOURCE: Fred Ranck For transportation professionals, safety is a major concern.
Intersections are the scene of many accidents. PHOTOGRAPHY SOURCE: Fred Ranck Transportation professionals are always looking for ways to reduce the number and severity of crashes.
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.
What is the effect on severe injury 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.
How do typical types of crashes compare between conventional intersections and roundabouts? Urban Signalized Intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts? Suburban Signalized Intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts? AWSC intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts? Rural TWSC intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts? Suburban TWSC intersection Roundabout
How do typical types of crashes compare between conventional intersections and roundabouts? Urban TWSC intersection Roundabout
Typical types of crashes at roundabouts Examples of Loss of Vehicle Control
Bicycle and Pedestrian Considerations PHOTOGRAPHY SOURCE: Lee Rodegerdts Intersections also introduce concerns for transportation professionals on the safest way to accommodate pedestrians and cyclists.
Pedestrian Considerations at Roundabouts PHOTOGRAPHY SOURCE: Lee Rodegerdts Data on pedestrian/motor vehicle crashes is very limited.
How do typical types of pedestrian/motor vehicle crashes compare between conventional intersections and roundabouts? PHOTOGRAPHY SOURCE: Lee Rodegerdts 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.
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 PHOTOGRAPHY SOURCE: Lee Rodegerdts
Bicycle Considerations PHOTOGRAPHY SOURCE: Lee Rodegerdts
Cyclist Movements at Roundabouts – Circulating as a Vehicle. Bikes re-enter bike lane Fewer conflict points with motor vehicles Lower motor vehicle speeds (15-20 mph) Bikes merge with motor vehicles 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.
Cyclist Movements at Roundabouts – Circulating as a Pedestrian. Bikes return to bike lane Bicyclists cross as pedestrians Bikes join shared path with pedestrians If a cyclist is uncomfortable riding with traffic, a cyclist can choose to travel instead as a pedestrian.
Summary of the Safety Features of Roundabouts • Travel speeds generally reduced by traffic calming effects • In almost all cases, the total number of crashes is reduced when a conventional intersection is replaced with a roundabout PHOTOGRAPHY SOURCE: Lee Rodegerdts • And more importantly, the number of severe injury crashes is dramatically reduced due to the roundabout’s common direction of travel and similar speeds