This school is pretty chill for a student dying in an accident.
If it happened in any school we would see a shrine made for her, candles surrounding her desk and so on.
I feel like the narrator here is unreliable in that she might have had a bad car accident but because there is no funeral or we don't see a body she could be in a comma with her spirit having left her body.
I am getting some "Midori no Hibi" vibes from this manga.