The South Australia helmet law came into effect from July 1991. It applies to all ages.
Helmet use increased from 40% to 90% upon introduction of the law.
The law is strictly enforced in most places but also much contested. From 2000 to 2003, South Australian cyclists paid AUD500,000 in fines for not wearing helmets (Advertiser, 2003).
Effect on casualties
The rate of head injuries declined both before and after the helmet law, with no obvious improvement in reduction around the time of the law. The decrease in concussions was greater than the decrease in other head/face injuries. (Marshall and White, 1994)
The Office of Road Safety, in reporting its evaluation of helmet legislation, said "Due to the disparate nature of the results from different sources, it is not possible to be conclusive about the effect of the requirement to wear bicycle helmets on the number of cyclists.". The report noted a 1994 study by Harrison of school children that showed a 38% decline in cycling from September 1988 to March 1994. This is likely to under-estimate the decline due to the helmets law because cycling is more popular in March than September in southern Australia.
The Advertiser. 19 December 2003.
Marshall J, White M, 1994. Evaluation of the compulsory helmet wearing legislation for bicyclists in South Australia. South Australia Dept of Transport Report 8/94.