Congestion is a persistent and expensive problem, costing the nation collectively over $300 billion each year. Cities have generally attempted to address congestion using an unoriginal set of expensive strategies, like building new roads or expanding public transit, and many cities are considering implementing congestion pricing. Expanding school bus service may be a palatable solution because it provides a service instead of involving lengthy and costly construction or charging a new fee. School travel is also a sizeable portion of total daily tra c. Indeed, over 50 million children travel to and from school each day and their commutes account for about one-quarter of total daily commuter trips. School travel and school-provided transportation is generally the domain of school districts and not city governments and the school districts in most large cities are independent from city governments. This may lead to a coordination problem if school districts ignore congestion caused, or exacerbated by, school travel. To determine whether pupil transportation reduces congestion, I exploit the interaction of pupil transportation provision (variation in pupil transportation spending and school bus use within districts) and idiosyncratic, within-city and within-month variation in the percentage of weekdays that are instructional school days in a month. I build a rich, monthly, longitudinal data set for congestion, school days, and transportation policy for 51 cities from 2013 to 2019 and find congestion is significantly higher on school days and pupil transportation alleviates congestion caused by school children’s travel. A back-of-the-envelope calculation suggests cities should subsidize the additional spending needed by the school district to transport more students and lower congestion.