This article analyzes the traffic stop-to-deportation pipeline in New York State, how it harms children of immigrants, and how New York’s Greenlight Law seeks to disrupt it but has been hobbled by an implementation gap. It first establishes the phenomenon of the traffic stop–to-deportation pipeline by documenting how traffic stops are a key cause of deportations in New York State. Second, it analyzes how the pipeline harms (mostly US citizen) children of undocumented immigrants in New York State, who are more than 7 percent (more than 300,000) of New York State’s children. The pipeline makes these children fear and mistrust the police; harms their educational, social, and brain development; and consumes family income with the Mexican driver tax (costs incurred because parents could not get a driver’s license). Third, the article analyzes how the Greenlight Law should help remedy these harms, and how an implementation gap leaves many parents and children vulnerable to the pipeline. The implementation gap is partly due to the pandemic but also driven by political and other factors that could be addressed by policy. Finally, the article analyzes how variation in implementing the Greenlight Law could leave the pipeline undisrupted and lead to unequal protection of the law by place in New York State. The article makes policy recommendations for stronger enactment to reduce the pipeline’s harms.