No, not every student is automatically eligible.
Bus transportation eligibility established by state law
State law establishes who qualifies for bus service by defining the distance a student can walk to get to school.  If the walking distance between the primary residence and the school is more than one mile for elementary students, or more than 1.5 miles for middle and high school students, the student is eligible for bus transportation.
A student who lives within the state defined walking distance to school may be eligible for bus service if the only walk path available has been deemed hazardous by the district.