The rear flashing safety flag on a Bluebird school bus. Glenview Illinois USA. August 2011., a photo by Eddie from Chicago on Flickr.
A modern safety feature that has began to show up recently on some Chicago area school buses, is the flashing rear sfety flag.
Until recently, most school buses in Illinois only had the front flashing safety flag next to the driver's side window.
Dual flashing safety flags, gives passengers either boarding or departing from the bus, a safe cushion of distance from cars attempting to pass the bus.