General sources:

• https://www2.gov.bc.ca/assets/gov/driving-and-transportation/transportation-infrastructure/engineering-standards-and-guidelines/traffic-engineering-and-safety/traffic-engineering/traffic-management-and-traffic-control/pedestrian-crossing-manual.pdf
• https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter5.htm
• https://nacto.org/publication/urban-street-design-guide/intersection-design-elements/traffic-signals/fixed-vs-actuated-signalization/

Image sources:

• https://www.iconarchive.com/show/free-flat-sample-icons-by-thesquid.ink/traffic-light-icon.html
• https://www.greatersudbury.ca/live/transportation-parking-and-roads/traffic-management-and-road-safety/traffic-signals/