Daash said:
Check this link on the requirement by Canada on Vision for a DL:
http://www.eyesite.ca/english/program-and-services/policy-statements-guidelines/drivingstd.html
The major dysfunction is with red/green and yellow in majority of colour blind people.....I guess the DL will have special medical notes. Maybe a stricter policy is in place for very rare case of total col blindness wherein only Black and white is visible....although I believe, B/W col blind people can differentiate between the hues and gradation/intensity/shades of colours. Also as the pattern of lights that appears is same world wide which is red, yellow and then green....people self teach or are advised accordingly.
mitali
