How effective is public service advertising in preventing risky road user behaviour?

Public service advertising as a separate measure usually has little effect on road user behaviour and road safety. Public service advertising campaigns coupled with enforcement (fines and/or rewards) do have positive effects on road user behaviour. This does not imply that public service advertising on road safety may be dispensed with. For, it may lead to increased knowledge and a change in attitude, and it may broaden support for effective but unpopular measures (also see SWOV fact sheet Public service advertising).