They also have 'shift changes' at the 7th Avenue/Washington-Jefferson St Bridge intersections.   Those shift changes don't inhibit the  pedestrian or bicycle traffic in the area, however.  My observation is that all of the prime panhandling spots in Eugene-Springfield-Glenwood have some sort of informal shift change procedure worked out by those who 'fly sign', as it's termed.  Entrepreneurs  at the basic level.  It's just business; nothing personal.  Last summer, the shift change at the Springfield bridge into Glenwood involved a white Ford Taurus Station wagon and a male and female on alternating shifts between 11:00 am until 2:00 pm each day that I noticed.