This study aimed to examine the effect of a penalty points system (PPS) implemented in early July 2006 on the number of severe road traffic injuries (RTIs) in Kuwait. Monthly counts of RTIs that occurred between January 2003 and December 2009 were analyzed. We used an interrupted seasonal autoregressive integrated moving average model (SARIMA) to estimate the intervention parameter along with its 95 percent confidence interval (CI) after accounting for seasonal and trend components in the data series. Based on the SARIMA model, we computed the number of RTIs that would have occurred post-PPS for 42 months after July 1, 2006, if it had not been implemented. During the study period, a total of 4696 RTIs occurred. The Poisson rates of injuries (per 10 million of mean mid-year population and per 10 million of annual mean number of registered vehicles) were significantly (P < .001) lower in the post-PPS (λ(post-PPS) = 7 and 16, respectively) than the pre-PPS (λ(pre-PPS) = 9 and 23, respectively) implementation period. The intervention parameter's estimate was -7.68 (95% CI: -14.77, -0.60), suggesting that 322 (95% CI: 25, 620) individuals would have had RTIs in the 42 months post-PPS enactment, had it not been implemented. This translates to a 14.6 percent (95% CI: 1.1%, 28.0%) reduction. These findings suggest that PPS implementation in Kuwait appears to have resulted in a significant reduction in the number of RTIs in the ensuing period. Therefore, PPS seems a feasible and effective approach in reducing RTIs in Kuwait and other countries in the region, if adequately implemented. Future studies may focus on evaluating the long-term effects of PPS implementation.