Using social return on investment analysis to calculate the social impact of modified vehicles for people with disability

Introduction: Returning to driving is often a goal for people with acquired disabilities. Vehicle modifications make it possible for people with both acquired and lifelong disabilities to drive yet can be costly. There has been no financial evaluation of vehicle modifications in Australia or internationally. Methods: A social return on investment analysis of vehicle modifications was undertaken. Primary data were collected via qualitative interviews with consumers and other stakeholders (e.g. driver-trained occupational therapists, rehabilitation physicians, driving instructors, vehicle modifiers) (n = 23). Secondary data were collected from literature searches and used to identify suitable financial proxies and make estimations of the proportion of drivers with vehicle modifications experiencing each outcome. A co-investment model was adopted to estimate social return on investment and payback period for funder and consumer. Five scenarios were developed to illustrate social return for low-cost modifications (Scenario 1) through to high-cost modifications (Scenario 5). Results: Social return on investment ratios was positive for funder and consumer investment in all five scenarios. Social return on investment calculations based on co-investment ranged from $17.32 for every $1 invested (Scenario 1) to $2.78 for every $1 invested (Scenario 5). Consumers' payback periods were between 5.4 and 7.1 months, and funders between 3.5 weeks and 2 years 8.4 months. Conclusion: Vehicle modifications represent sound investments for both funders and consumers. Given the short payback periods, funders should reconsider age restrictions on vehicles considered suitable for modifications, especially for low- to medium-cost modifications.