Ditto all advice about taking the bus out of UC. They have seemingly a whole fleet of them loading and departing constantly. They've been doing it after Bulls and Blackhawks games and other concerts for years, so they have it down to a science. Actually, the time it takes to evacuate UC is surprisingly fast compared to other cities we've been to. Take a bus to the loop, and hook up with other transport there. It's never been a problem for us in terms of safety. Another side note, U2 fans in Chicago always seem to be even more courteous than in other cities. Chicago is fun town to see the band.
Got my Chicago GA tix for June 24! But not without sweating it out during a one hour ordeal. Got repeated 401 error messages, had to re-enter presale code multiple times, also "experienced" the infamous spinning wheel of death, then on a whim I went to another computer at work and after about an hour (11am Central) I got right on through the process. Click, click, click, bang bang and purchased. What a relief to see that receipt in my inbox! Bottom line, DON'T GIVE UP! Remember the general public can't get a hold of any tickets till Monday. Keep trying and KEEP COOL!