Collisions and injuries –some of them fatal – very often occur at intersections. The victims are usually the most vulnerable road users (i.e., children, older pedestrians, and bicyclists). If not killed outright, victims can suffer serious and sometimes devastating, lifelong injury.
According to the National Collision Database, In 2020, 27 percent of traffic fatalities and 41 percent of serious injuries occurred at intersections in Canada.
At intersections with traffic signals, some of the most effective safety measures involve separating road users in time and space. Examples of separating road users in time include protected-only left-turn phases, leading pedestrian intervals, and separate signal phases for bicycle and pedestrian movements. Examples of separating road users in space include high visibility crosswalks, designated bicycle crossings, and small corner radii which reduce turning speed and expand the pedestrian area, creating a safer environment for all users. In combination, these measures create what is referred to as a “Protected Intersection”, illustrated below here.
One of the most effective intersection measures is the modern roundabout shown above (https://www.iihs.org/topics/roundabouts). Roundabouts significantly reduce right-angle (side-impact) and head-on collisions (i.e., when a vehicle is turning left), and therefore can prevent most intersection-related fatalities and serious injuries by requiring vehicles to slow down, approach at an angle, and yield to traffic already on the roundabout before entering https://www.iihs.org/topics/roundabouts.
Road agencies typically conduct Network Screening, which identifies collision-prone intersections, and carry out Road Safety Audits (at the planning or design stage) or In-Service Road Safety Reviews of existing intersections to identify opportunities for reducing the risk of collisions and injuries.
- International Road Engineering Safety Countermeasures and their Applications in the Canadian Context (Transport Canada, 2010) https://tc.canada.ca/sites/default/files/migrated/rs_engineer_10_29_2010_en.pdf
- Methods of Reducing Collisions on Alberta Roads (Alberta Transportation, 2010) http://www.transportation.alberta.ca/PlanningTools/Documents/Morcoar/MORCOAR%20Phase%202%20FINAL%20Report.pdf
- The BC Community Road Safety Toolkit (2016) https://www2.gov.bc.ca/gov/content/transportation/driving-and-cycling/road-safety-rules-and-consequences/bc-community-road-safety-toolkit
- The Highway Safety Manual (AASHTO, 2010) http://www.highwaysafetymanual.org/Pages/default.aspx
- Office of Safety Proven Safety Countermeasures (US Federal Highway Administration web resources) https://safety.fhwa.dot.gov/provencountermeasures/
- Urban Street Design Guide (NACTO web resources) https://nacto.org/publication/urban-street-design-guide/intersection-design-elements/