Bicyclists running stop signs

What's up with these bicyclists blowing through stop signs and ignoring red lights? Cornelia and Halsted, Halsted and Belmont, and Belmont/Clark/Halsted are among the worst locations. Just the other day I was crossing in the pedestrian crosswalk at Cornelia and Halsted and bikers from both north and south directions blew through and nearly knocked me down. I yelled at one bimbo "You ran a stop sign!" and you kinow what she did? Gave me the finger!!!! The nerve!!!! But I know nothing will be done. I've witnessd cyclists blowing red lights right in front of cop cars, nothing is done.