Road traffic injuries (RTIs) are commonly under-reported in low- and-medium-income countries. This study aimed to estimate the number of RTIs and determine the magnitude of under-reporting by traffic police and hospital registries. The police registry captured 14.4% of the estimated number of RTIs and the hospitals captured 60.4%. The estimated number of RTIs was higher than reported by either the police or the hospitals alone. Neither the police nor the hospitals provided accurate data on RTIs, calling for the strengthening of both sources of data.