Strictly speaking, not a speed trap, but designed to trap motorists who do not yield to pedestrians in cross-walks. If you are driving west (say) and somebody steps off the south curb (on your left — across the street from you), you are supposed to stop even if you’re already only 10 or 15 feet from the intersection going the legal 25 mph. That means coming to a screeching stop for somebody who won’t be in front of you for at least 5 seconds or more.