From 'car-dependency' to 'desirable walking' : 15 years trend in policy relevant public health indicators derived from Household Travel Surveys

Reducing car dependency in favour of health-enhancing active travel can address the issues of prolonged sitting and physical inactivity. This study utilises transportation-sector population surveys to develop interdisciplinary policy relevant indicators for benchmarking and progress tracking. The continuous Sydney Greater Metropolitan Household Travel Survey (2000-June 2015) was analysed in 2017. The prevalence of adults (≥15 years old) who i) travelled by car for distances amenable for health-enhancing walks (≤ 1.5 km,≤2.0kms); ii) only drove a car and did not walk, including no walks that link to other modes (i.e, CD: 'car-dependency'); and iii) walked≥30 min, or≥3 kms, or>3 walking trips (i.e., DW: 'desirable walking') in the past 24 hours were examined including prevalence ratios for CD/DW by population sub-groups (e.g., age, gender, employment status, income and household structure) and by statistical districts located within short (<13kms), medium (13-30kms) and long (>30kms) driving distance from Sydney Central District.The adjusted yearly decline in the prevalence of CD was small (0.3%) but significant, from 40.3% (95% CI: 39.6 - 41.1) in 2000/3 to 39.3% (38.1-40.1) in 2012/14. DW remained unchanged, from 20.6% (95% CI: 20.0; 21.2) to 21.2% (95%CI: 20.6-21.9). The CD/DW prevalence ratio varied greatly by distance from Sydney city, with medians ratios 0.86, 1.86 and 3.25 in short, medium and long distance categories, respectively, and by demographic sub-group (range from 0.64 to 2.67). The yearly prevalence ratios of CD/DW presented a declining trend from 1.42 to 1.13, after adjustment for population demographic characteristics. Across all periods 21% travelled by car for≤1.5kms, of those travellers 44% were car dependent. These indicators can serve both transportation and health sectors wherever transport surveys exist, for benchmarking, monitoring and setting area- specific goals that are aligned with public health and transport policies.