the hawthorne bridge bike counter! i think it said 582 at the time i took the pic (sunday afternoon, 14.04.13). i wonder where the detector is, though.. do all cyclists turn right or do some go straight? are they both counted? does it count bike traffic on the other direction?
edit: answers here at oregonlive, 17.03.13. and the counter was donated by cycle oregon. results of daily bike counts here.