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Safety Elements ofModern Roundabout
ProWalk/ProBike
September 8, 2004
Michael M. Moule, PE, PTOE
Weaver Blvd @ UNC-Asheville Main Entrance
Crash Statistics - The Netherlands
Source: FHWA Roundabout Guide
Crash reductions by mode at intersections converted to roundabouts
Intersection Size Affects Safety
Motor Vehicle Conflict Points
4-way intersection Roundabout
Source: FHWA Roundabout Guide
Motor Vehicle Conflict Points
4-way intersection
4-way Intersection Roundabout
32 total conflicts 8 total conflicts
Source: FHWA Roundabout Guide
Motor Vehicle Conflict Points
4-way intersection
4-way Intersection Roundabout
32 total conflicts 8 total conflicts
8 merging conflicts 4 merging conflicts
8 diverging conflicts 4 diverging conflicts
Source: FHWA Roundabout Guide
Motor Vehicle Conflict Points
4-way intersection
4-way Intersection Roundabout
32 total conflicts 8 total conflicts
8 merging conflicts 4 merging conflicts
8 diverging conflicts 4 diverging conflicts
16 crossing conflicts 0 crossing conflicts
Source: FHWA Roundabout Guide
Motor Vehicle Conflict Points
4-way intersection
4-way Intersection Roundabout
32 total conflicts 8 total conflicts
8 merging conflicts 4 merging conflicts
8 diverging conflicts 4 diverging conflicts
16 crossing conflicts 0 crossing conflicts
High Speed,High Angle Crashes
Low speed, Low angle crashes
Source: FHWA Roundabout Guide
Motor Vehicle Crash Statistics
Source: FHWA Roundabout Guide
Motor Vehicle Crash Statistics
Source: FHWA Roundabout Guide
Pedestrian Conflict Points
Source: FHWA Roundabout Guide
Peds threatened from afar by high-speed Red Light Runners
Red lights
Ped threatened from behind by left-turning vehicle
Ped threatened from behind by right-turning vehicle
Ped threatened by vehicle turning right on red
Pedestrian Conflict Points
4-way intersection
4-way Intersection Roundabout
16 conflicts 8 conflicts
Source: FHWA Roundabout Guide
Pedestrian Conflict Points
4-way intersection
4-way Intersection Roundabout
16 conflicts 8 conflicts
High Speed Crashes Low speed crashes
Source: FHWA Roundabout Guide
Speed & Pedestrian Crash Severity
Pedestrian Crash StatisticsGreat Britain
Source: FHWA Roundabout Guide
Bicycle Conflict Points4-way Intersection
Source: FHWA Roundabout Guide
Conflicts in common with motor vehicles
Conflicts unique to bicycles
Bicycle Conflict PointsRoundabout
Source: FHWA Roundabout Guide Bicyclist traveling as a pedestrian
Bicyclist traveling as a vehicle
Bicycle Conflict Points
4-way intersection
4-way Intersection Roundabout
Left turn: 8 veh. conficts Left turn: 5 veh. conficts
Left turn: 2 ped conflicts Left turn: 2 ped conflicts
Source: FHWA Roundabout Guide
Bicycle Conflict Points
4-way intersection
4-way Intersection Roundabout
Left turn: 8 veh. conficts Left turn: 5 veh. conficts
Left turn: 2 ped conflicts Left turn: 2 ped conflicts
Through: 6 veh. conflcts Through: 4 veh. conflcts
Through: 2 ped conflicts Through: 2 ped conflicts
Source: FHWA Roundabout Guide
Bicycle Conflict Points
4-way intersection
4-way Intersection Roundabout
Left turn: 8 veh. conficts Left turn: 5 veh. conficts
Left turn: 2 ped conflicts Left turn: 2 ped conflicts
Through: 6 veh. conflcts Through: 4 veh. conflcts
Through: 2 ped conflicts Through: 2 ped conflicts
High Speed,High Angle Crashes
Low speed, Low angle crashes
Source: FHWA Roundabout Guide
Bicycle Crash StatisticsGreat Britain
Source: FHWA Roundabout Guide
Crashes per million trips
Crash Statistics - France
Source: FHWA Roundabout Guide
Crash percentage per type of user - France
Source: FHWA Roundabout Guide
Crash Statistics - The Netherlands
Source: FHWA Roundabout Guide
Crash reductions by mode at intersections converted to roundabouts
“No design can be made idiot proof.”
