This paper presents cost-outcome analyses of four transportation injury prevention efforts in Native American jurisdictions. Pre- and post-intervention data were analyzed to estimate projects’ impact on injury reduction. Projects’ costs were amortized over the time period covered by the evaluation or over the useful life of physical capital invested. Projects’ savings were calculated based on estimated reduction in medical and public program expenses, on estimated decrease in lost productivity, and on estimated quality adjusted life years saved. All four projects yielded positive benefit-cost ratios. The net cost per quality adjusted life years was less than zero for all the projects.