An awareness campaign based on using juice/milk/whatever drink cartons' "real estate" & distribution channels. The cartons work as "outdoors" while they are on the shelves, and then as flyers once they're on the table.
Barrier This Solves
Unfavourable cultural environment, cyclists as an out-group, lack of knowledge on lawful and fair behaviour by people who drive cars, lack of good traffic skills by cyclists.
This increases chances for conflicts to come up or to be ill resolved.