Looking at information from Australia and providing very rough calculations to illustrate how the rate of TBI may change. http://www.cycle-helmets.com/au-assessment-2015.pdf
Referring to Tables 3 and 4, Table 3 accidents involving motor vehicles roughly shows head and concussions to be 12% for the 0-17 age range v 7.6% for 18+age group
Table 4 shows the serious injury rates per 10 million km. This can roughly be related to hours cycled. It reports;
Roughly, the 9-16 age group had a rate of 55 and the 17-64 age group a rate of 20 and for age 65+ a
rate of 110 per 10 million km. Indications are that the 65+ group comprised about 1% of distance cycled, the
0-16 age group about 60%, and the 17- 64 age group about 39%.
Assuming TBI is related to serious accidents and in proportion to TAC data, Table 3 data, serious injury and proportion of head/concussion by age group, (not actual NZ data for TBI but using NZ data for hours cycled)
55 x .12 v 20 x 0.076 – 6.6 v 1.52
Hours cycled for NZ in Table 4 https://www.researchgate.net/publicatio ... jury_rates
23 million for the 5-17 age range v 16 million for 18+ range in 1989/90 ,
23 x 6.6 v 16 x 1.52 – 152 v 24 – total 176 from 39 million hours, 4.5 per million hrs
for the 2006/09 period, roughly 6 million hrs for the 5-17 age group v 17 million for 18+
6 x 6.6 v 17 x 1.52 – 39 v 26 – total 65 from 23 million hours, 2.82 per million hrs
This would equate to a 37% reduction in the rate of TBI due to the change in the proportion cycling.
In addition road safety improved, motorcyclists had 51% reduction in the rate of serious injuries by 2003/07.
Clarke looked at the overall trends in fatalities and other issues, all the data from Tin Tin et al was already known and Tin Tin was unsure what the reduction in TBI was due to. if a follow up evaluation of the NZ helmet law was produced I think it would try to include more detailed information on head and TBI data.
All the general findings of the Clarke paper seem valid and more recent research shows the damage that has resulted from the helmet law and helmet use.
and https://www.researchgate.net/publicatio ... w'_article http://www.nzma.org.nz/journal/read-the ... -1402/6298
Reply to Wang et al response to ‘Evaluation of New Zealand’s bicycle helmet law’ article
12th September 2014, Volume 127 Number 1402https://www.tandfonline.com/doi/abs/10. ... ode=ibjn20