Model input parameters*
| Parameter | Estimate (range) | References |
|---|---|---|
| Population of Vietnam | 84 000 000 | 16 |
| Prepolicy RTI deaths | 13 000 | 14 |
| Prepolicy non-fatal RTIs | 445 000 | 14 |
| Proportion of RTI deaths attributable to motorcycles (%) | 58 (51–73) | 9 21 22 |
| Proportion of non-fatal RTIs attributable to motorcycles (%) | 59 (51–75) | 7–9 21 22 |
| Proportion of non-fatal motorcycle RTIs with head injury (%) | 21 (10–32) | 23 |
| Prepolicy helmet use (%) | 30 (20–40) | 7 8 |
| Postpolicy helmet use (%) | 93 (83–98) | 8 |
| Average direct acute-care cost of non-fatal RTI with a helmet (US$) | 436 (366–506) | 23 |
| Average direct acute-care cost of non-fatal RTI without a helmet (US$) | 559 (416–702) | 23 |
| Expected increase in treatment cost for 10$ increase in income (%) | 1 | 23 |
| Income loss (weeks) | 32 | 22 |
| Mean per capita income, by quintile (US$) | 305, 530, 777, 1185, 2730 | 24 |
| Motorcycle ownership distribution by quintile (%) | 20, 35, 54, 73, 94 | 25 |
| RR of death, helmet vs no helmet | 0.58 (0.50–0.79) | 26 |
| RR of injury, helmet vs no helmet | 0.31 (0.25–0.66) | 26 |
| Per capita cost of policy implementation (US$) | 0.29 | Ref. 27 (correspondence from Dan Chisholm) |
*Online supplementary appendix table S1 provides the detailed rationale and additional sources for selection of point estimates and ranges.
RTI, road traffic injury.