page_title: Roundabout
section_title: Safety
hierarchical_section_title: Roundabout / Safety
caption_attribution_description: English: Carland Cross roundabout on the A30 road in Cornwall
context_page_description: A roundabout is a type of circular intersection or junction in which road traffic is permitted to flow in one direction around a central island, and priority is typically given to traffic already in the junction.
  Modern roundabouts observe various design rules to increase safety. Compared to stop signs, traffic signals, and earlier forms of roundabouts, modern roundabouts reduce the likelihood and severity of collisions greatly by reducing traffic speeds and minimizing T-bone and head-on collisions. Variations on the basic concept include integration with tram and/or train lines, two-way flow, higher speeds and many others.
  Traffic exiting the roundabout comes from one direction, instead of three, simplifying the pedestrian's visual environment. Traffic moves slowly enough to allow visual engagement with pedestrians, encouraging deference towards them. Other benefits include reduced driver confusion associated with perpendicular junctions and reduced queuing associated with traffic lights. They allow U-turns within the normal flow of traffic, which often are not possible at other forms of junction.
context_section_description: Statistically, modern roundabouts are safer for drivers and pedestrians than both traffic circles and traditional intersections. Roundabouts are safer than both traffic circles and junctions—experiencing 39% fewer vehicle collisions, 76% fewer injuries and 90% fewer serious injuries and fatalities (according to a study of a sampling of roundabouts in the United States, when compared with the junctions they replaced). Some larger roundabouts take foot and bicycle traffic through underpasses or alternate routes.
  At junctions with stop signs or traffic lights, the most serious accidents are right-angle, left-turn or head-on collisions where vehicles move fast and collide at high impact angles, e.g. head-on. Roundabouts virtually eliminate those types of crashes. Instead, most crashes are glancing blows at low angles of impact.
  An analysis of the New Zealand national crash database for the period 1996–2000 shows that 26% of cyclists reported injury crashes happened at roundabouts, compared to 6% at traffic signals and 13% at priority controlled junctions. The New Zealand researchers propose that low vehicle speeds, circulatory lane markings and mountable centre aprons for trucks can reduce the problem.
  The most common roundabout crash type for cyclists, according to the New Zealand study, involves a motor vehicle entering the roundabout and colliding with a cyclist who already is travelling around the roundabout (50%+ of cyclist/roundabout crashes in New Zealand fall into this category). The next most common crash type involves motorists leaving the roundabout colliding with cyclists who are continuing farther around the perimeter.
caption: A typical trunk road roundabout in the UK at Carland Cross on the A30 in Cornwall. There is a free-flow lane for the A30 towards Bodmin (nearest the camera).
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