Why has public transit ridership declined in the United States?

•Between 2012 and 2018, bus ridership in the US declined 15% and rail ridership declined 3%.•We identify the factors responsible and quantify the contribution of each.•Expanded transit service and land-use changes would have led to higher ridership but were offset by other factors.•Ride-hailing is the biggest contributor to transit ridership decline.•Higher fares, incomes, teleworking and car ownership, and lower gas prices also contribute.