Shown here are two sets of important data, as reported in the STN 2005 Buyer's Guide from the states. First, the number of school days or instructional days required of K-12 students in each state. Second, based on that figure, the estimated number of annual student trips by state.

The Annual Student Ridership Formula multiplies one-way daily ridership by two to calculate the morning and afternoon trips, adds an estimated 10 percent more rides for extracurricular or activity trips, and then multiplies that figure by the number of school days.

In addition to the student rides provided during the regular school year, the Annual Student Ridership Formula estimates an additional, minimum, one billion rides for private school and Head Start transportation during the regular school year, and summer school service.