The dynamism of the national economy requires sustainable development, but road traffic crashes, acting as a structural barrier, impose heavy human and material costs on the Gross Domestic Product annually. This study aimed to evaluate the impact of "traffic culture" on Iran's economic growth during the period 1991-2021. To explain the equilibrium relationships among economic growth, the composite index of traffic culture (which integrates accidents as a negative score), infrastructure investment, and population, the Autoregressive Distributed Lag (ARDL) dynamic model was employed. The results indicated that in the long run, the current state of the traffic culture index has a deterrent and negative effect on economic growth; meaning the costs of traffic anomalies have outweighed the benefits of behavioral improvements. Furthermore, infrastructure investment was identified as a positive driver of growth. Consequently, policymakers must shift from hardware-only approaches to promoting traffic culture as a "macroeconomic policy" to reduce human capital depreciation costs and achieve sustainable economic growth.