# Per capita cycling decline is correct

At Cycling rates are up, despite creaky knees and Gillham and Rissel reworked v2, Jake Olivier et al attempt to discredit Australian per capita cycling participation in 1985/86 and 2011 on the basis that the paper miscalculates the ageing of the population and that this means per day bicycle trips have in fact increased by 8% per capita during that time period.

Olivier et al base their proposition on the ratio of trips per population in each age category during 1985/86 and thus calculate the expected trips per day based on the ratio applied to the respective age category populations during 2010. They apply the ratio to each age, sum the total to 1,867,758 and maintain this is 8% below their estimated observation of 2,014,620 cyclists per day in 2010.

They apply the ratios to age brackets but don't apply their calculated 1985/86 ratio of 0.1326 to the total 2010 population of 19,515,563 people aged 9+, which results in an expected 2010 cycling rate of 2,587,764 trips per day - 28.5% more than the estimated/observed 2,014,620.

The Olivier et al argument relies primarily on the significant increase in numbers and proportion of Australians aged 30-59 - up from 5,300,685 in 1981 to 8,987,612 in 2010.

Their premise is that if 3.8% of the 30-59yo age bracket cycled per day in 1985/86, this should translate to 342,573 cycle trips per day in 2010. The cycling participation survey estimated 886,325 daily cyclist trips in 2011 in the 30-59 age category.

ABS population revision

Population estimates revised in 2013 by the Australian Bureau of Statistics change this equation to 3.6% x 8,987,612 = 323,554 cycle trips per day in the 30-59yo age bracket.

Applying appropriate 1985/86 ratios to all age populations in 2010, they calculate the expected total based on 1985/86 ratios at 1,867,758. ABS population revisions have changed this total to 1,844,536.

All surveys show that child cycling was the most discouraged as a result of helmet law enforcement in 1990/92. Increased adult participation numbers are disputed by various studies, particularly work commuter surveys which showed a significant and persistent cycling decline over 25 years.

However, it is agreed there was a substantial shift in the respective age proportions of cycling participation and it is probable that baby boomers who enjoyed cycling in their youth continued or resumed this activity to counter petrol price, congestion and health concerns during the 25 years.

The most reliable way to apply 1985/86 ratios to 2010 is to use the 85/86 total persons ratio of 0.1326, which results in 2,587,764 expected cyclists in 2011. Alternatively, revised ABS population data creates a 1985/85 ratio of 0.1287, which results in 2,480,233 expected cyclists in 2011.

9-17yo

If the critique logic is applied to the 10-17yo age group using the 1985/86 ratios for 9-15yo (0.4753), 16yo (0.5641) and 17yo (0.3398), expected trips per person in 2011 were 1,069,186 - as detailed by Olivier et al. However, the 2011 participation report shows there were an estimated (observed) 592,588 trips per day among the 10-17yo age bracket in 2011.

This is comparing 9-17yo in 1985/86 with 10-17yo in 2011. Applying revised ABS population data, the 2011 total for 9-17yo cyclists is 670,143. This is 383,670 or 35.9% below the expected daily cycling participation of 1,069,186 in the 10-17yo age category.

In 1985/86, the population of 9-17yo was 2,449,000 and in 2010 it was 2,522,582, an increase of 3%.

18-24yo

In the 18-24 age category, the 1985/86 ratio resulted in an expected total of 238,089 in 2011. The 2011 cycling participation report observed 194,225 trips per day in this age bracket in 2010. This is 18.4% fewer than expected. In 1985/86, the population of 18-24yo was 1,618,000 and in 2010 it was 2,268,228, an increase of 40.2%.

Revised ABS population data show that in the 18-24 age category, the 1985/86 ratio resulted in an expected total of 211,464 in 2011. The 2011 cycling participation report observed 189,170 trips per day in this age bracket in 2010. This is 11.8% fewer than expected. Revised ABS data show that in 1985/86, the population of 18-24yo was 1,836,637 and in 2010 it was 2,209,188, an increase of 20.3%.

10-24yo

Cumulatively aged 10-24, there was an expected 1,307,275 but a realised 786,813 - which is 520,462 or 38.1% fewer cyclists than expected.

Revised ABS population data show that cumulatively aged 10-24, there was an expected 1,307,740 but a realised 772,398 - which is 535,342 or 40.9% fewer cyclists than expected.

25-29yo

In the 25yo category, the 1985/86 ratio (0.0647) resulted in an expected total of 22,213 in 2011, and in the 26-29yo category (0.0771) resulted in an expected total of 104,953 in 2010. This is 127,166 aged 25-29. The 2011 cycling participation report observed 179,848 trips per day in this age bracket in 2010. This is an increase of 41%. In 1985/86, the population of 25-29yo was 1,193,000 and in 2010 it was 1,665,263, an increase of 39%.

Revised ABS population data show that in the 25yo category, the 1985/86 ratio (0.0598) resulted in an expected total of 19,882 in 2011, and in the 26-29yo category (0.0762) resulted in an expected total of 99,249 in 2010. This is 119,131 aged 25-29. The 2011 cycling participation report observed 176,375 trips per day in this age bracket in 2010. This is an increase of 48.1%. In 1985/86, the population of 25-29yo was 1,229,982 and in 2010 it was 1,633,102, an increase of 32.8%.

30-59yo

In the 30-59yo category, the 1985/86 ratio (0.0380) resulted in an expected total of 342,573 in 2011. The 2011 cycling participation report observed 886,326 trips per day in this age group in 2010. This is an increase of 158.7%. In 1985/86, the population of 30-59yo was 5,095,000 and in 2010 it was 9,074,202, an increase of 78.1%.

Revised ABS population data show that in the 30-59yo category, the 1985/86 ratio (0.0360) resulted in an expected total of 321,225 in 2011. The 2011 cycling participation report observed 877,568 trips per day in this age group in 2010. This is an increase of 173.2%. In 1985/86, the population of 30-59yo was 5,300,685 and in 2010 it was 8,987,612, an increase of 69.6%.

60+

In the 60-64yo category, the 1985/86 ratio (0.0359) resulted in an expected total of 43,893 in 2010, and in the 65+ category (0.0147) resulted in an expected total of 46,747 in 2010. This is 90,640 aged 60+. The 2011 cycling participation report observed 161,632 trips per day aged 60+ in 2010. This is an increase of 78%. In 1985/86, the population of 60+ was 2,133,000 and in 2010 it was 4,221,651, an increase of 97%.

Revised ABS population data show that in the 60-64yo category, the 1985/86 ratio (0.0409) resulted in an expected total of 51,000 in 2010, and in the 65+ category (0.0144) resulted in an expected total of 45,440 in 2010. This is 96,440 aged 60+. The 2011 cycling participation report observed 160,820 trips per day aged 60+ in 2010. This is an increase of 66.8%. In 1985/86, the population of 60+ was 2,068,142 and in 2010 it was 4,191,418, an increase of 102.7%.

Total proportions

Olivier et al suggest there were an estimated 2010 cycle trips per day of 2,014,620, 1,990,100 or 1,995,925, based on different criteria within the cycling participation report. Gillham and Rissel calculate cycling participation in the 10-17, 18-39 and 40+ age groups with ratios estimating a total 1,989,562 Australians aged 10+ cycled daily in 2011.

The age specific vs total calculation does not change the outcome. Total population increased at a faster rate than total cycling participation, regardless of more cycling per capita among the middle aged.

Olivier et al estimate 2,014,620 cycling trips per day in 2011, compared to 1,656,100 in 1985/86 - a 21.6% increase. This compares to a total 9+ population of 12,488,000 in 1985/86 and a 10+ population of 19,515,563 in 2010 - a 56.3% increase. The 34.7% discrepancy corresponds with an estimated 30-40% decline in all age cycling participation following Australian helmet law enforcement in 1990/92.

The Olivier et al critique and the Gillham/Rissel results are based on the 1981 Census (12,488,000 aged 9+), not 1986 population figures (13,867,351 aged 9+), an 11.1% increase. There is evidence that public cycling participation was increasing around 10% per annum from 1986 to 1990 when Australia's first helmet law was enforced.

The 1985/86 survey was over all months including winter whereas the 2010 survey was in the warm months of March/April which are among the most popular for cycling. In the absence of government helmet surveys there is anecdotal evidence that by 2010 a large proportion of new cyclists were not wearing helmets.

These variables suggest Australia's reported cyclist numbers in 1986 were an underestimate, with participation likely to have been greater by 1990 when the first helmet law was introduced, and the 22.4% increase in Australian daily cyclist trips (1,645,900/2,014,620) is largely dependent upon cyclists breaking the law.

The total 1985/86 ratio applied to total population suggests a 28.4% decline in daily cycling participation.

In 1985/86 there were 1,656,100 daily cycling trips among 12,488,000 people aged 9+, which is a ratio of 0.1326. In 2011, there were 2,014,620 daily cycling trips among 19,515,563 people aged 10+, which is a ratio of 0.1032.

That is a 2.94% decline which within the 2010 population of 19,515,563 people aged 10+ estimates to 573,758 fewer people cycling per capita.

The downturn is mostly due to substantially less cycling among Australians aged below 25, the critical period of physical development that influences behaviour and health in adult life.

Although Olivier et al dispute the level of helmet law opposition and cycling discouragement in Australia, opinion polls and the failure of Melbourne and Brisbane bike share projects consistently suggest more adults would cycle if not discouraged by helmet laws.

Their critique uses age categories to refute the totals, even though their own figures show similar results, and the percentage decline of 28.4% translates to more than half a million Australians who would cycle at all or more frequently if the helmet law was repealed.

Note: The biennial update of the Australian cycling participation survey by the Australian Bicycle Council and Austroads has been released for 2013, showing a failure of the 2011-2016 National Cycling Strategy with a statistically significant decline in Australian cycling from 2011 to 2013. The 2013 survey shows a significant drop in the number of people cycling and a major reduction in the number of times they ride their bikes. If the Olivier et al critique methodology is applied to the 2013 rather than 2011 survey results, it shows a major decline in Australian cycling compared to population growth. Click for an update analysis.