DD attends the district where DH and I work as teachers (a privilege of employment) not where we are zoned, so we all carpool.
But, in the district where we are zoned (and in which there are no direct GT services!) students have to live 2 miles or more away from the assigned school to receive a bus pass. We live within the 2 mile radius so she wouldn't qualify. Our assigned school is across downtown Austin from us; without a parent provided car ride, she'd have to walk over a mile through high rise buildings, busy traffic, etc. (But not uphill in the snow both ways, haha.)
Lots of kids in our zoned district use public transportation since there isn't enough money for safe transportation for all students.