A set of guidelines (intended especially for children) for crossing the road safely, introduced in 1971 and subsequently incorporated in the Highway Code; also in extended use.
Origin
1970s; earliest use found in The Times.
Definition of Green Cross Code in US English:
Green Cross Code
noun
British
A set of guidelines (intended especially for children) for crossing the road safely, introduced in 1971 and subsequently incorporated in the Highway Code; also in extended use.