Travel behaviour in Brisbane: Trends, saturation, patterns and changes

Peak-car is characterised by slower rates of growth, levelling off, or a reduction in car travel. Researchers have paid much attention to this topic recently. However, a consensus on possible explanations of the phenomenon remains elusive. Questions remain whether the drivers of travel demand are changing and projection methods need to be revised, or the peak-car is purely an external effect (e.g. fuel price, financial crisis) and car travel continues to increase when such effects are nullified. The study investigates these issues focusing on Brisbane using six versions of the South East Queensland Household Travel Survey data (1992, 2003, 2006, 2009, 2012, and 2018). Three different analytical methods were employed. First, four pooled regression models were estimated to examine the effects of time (external effects) on travel behaviour, controlling for different socio-demographics and built environment factors. Second, five multiple linear regression models were estimated using 2003, 2006, 2009, 2012, and 2018 datasets to identify behavioural differences between different groups in a specific point in time. Third, differences in coefficients as generated in the second stage were estimated to understand whether the behavioural patterns are changing. The findings suggest that car travel in Brisbane: a) reached a peak in 2003; b) experienced a decline throughout 2003-2012; and c) exhibited a levelling off throughout 2012-2018. The factors contributed to the peak-car phenomenon in Brisbane are both external (global financial crisis, policy interventions in public transport) and a significant change in the coefficients of some internal factors over the periods (millennials, household size, population density).