Incentivising adults and young people to use public transport for physical activity gain

The study has a 14 week intervention phase followed by a 24 week maintenance phase. The 14 week intervention phase allows 10 weeks for behaviour change to reach automaticity and 4 weeks for maintenance or ‘tapering off’, where contact and support is gradually withdrawn in preparation for intervention cessation.Using a ‘gain-framed’ approach (i.e. rewarding positive behaviours), participants in the intervention group will have bus trip use targets from weeks 1-14 which escalate over the course of the intervention so that targets become more difficult to reach but incentive values increase (weekly bus trip targets are: weeks 1-3, one bus trip; weeks 4-6, two bus trips; weeks 7-9, three bus trips; week 10, four bus trips; weeks 11-12, 3 bus trips, week 13, three bus trips, week 14, three bus trips). If the bus trip target is met, participants receive bus trip credit (through their public transport smartcard). The credit received will be commensurate with the participant’s default fare type that they were required to set when applying for their smartcard. The price range of the different fare types is $1.52 to $5.76 (a child/student fare through to an adult fare with travel across multiple zones). The maximum credit a participant can receive by the end of the 14 week intervention phase is $48.64 if travelling on a child/student fare and if travelling as an adult $184.32 as per their default fare type. Participants will be aiming to achieve a minimum of three bus trips per week by the end of the intervention. Participants will be notified by a weekly email whether they have met or have not met their target (this data is provided by the transport company, Metro, after downloading weekly trip data from the participants' smartcard), the smartcard credit they have received (if any) and the following week’s target. There are no set targets for the distance walked to or from a bus stop. To assist participants to achieve the weekly targets and, consistent with best practice, incentives will be supported by other behaviour change techniques (e.g. information on consequences of behaviour to the individual, setting graded tasks, goal setting, social support), delivered via weekly mobile text messages (2 messages per week from weeks 1-12, 1 message per week, weeks 13-14). Development of the text messages was underpinned by the Behaviour Change Technique Taxonomy, informed by our previous qualitative work on transport behaviour and physical activity and from an incentive-based study designed to increase weekly leisure-time physical activity and reduce sitting time (Michie et al 2013, Ball et al 2017). Participants in the intervention group will also receive a printed version of Australia’s Physical Activity and Sedentary Behaviour Guidelines. All intervention support will be provided by an unblinded member of the research team.