Scuffham, Alsop, Cryer and Langley, 2000 claimed that the helmet law led to a 19% reduction in head injury to cyclists over its first 3 years. This is similar to the reduction in cycle use (see below). However, Robinson (BHRF, 1237) showed that there had been no reduction in head injuries to cyclists over and above the general trend experienced by the population as a whole. The sudden large increase in helmet wearing by adults and teenagers was not accompanied by a change in trends in head injuries for these groups. Perry, 2001 has also shown that the changes in head injuries for cyclists matched those of the population at large and not the cycle helmet wearing rate.
In 2006 it was reported that three-quarters of fatalities were still due to head injuries, although helmets were worn by 94% of cyclists (NZMT, 2007).
After an initial fall (but less than the decline in cycle use), hospital admissions of cyclists have increased since enactment of the helmet law: (NZMT, 2007)
No surveys to track cycle use were carried out to monitor the effect of the helmet law. However, the New Zealand Household Travel Survey (LTSA, 1993-7) shows that cycling decreased by approx 22% between 1993 and 1997.
In 2006/7 Land Transport NZ said that cycling had declined from 3.6% to 1.8% of traffic over an unspecified period. Cycle trips had fallen by 39% overall, but by 50% for young people aged 5 to 20 years (Hammond, 2010).