I ride this route daily, so perhaps can provide some add'l context. The lower level of the steel bridge is perfect for cyclists, as was intended, but sometimes riders are too impatient to wait for it to be lowered because of a boat and opt to go up. Also, I often see newbie riders get confused on how to get to the lower level and take the top route. Then when up, they see what the road is like and it is terrifying. It's two lanes of accelerating traffic that squeeze uphill onto a narrow single lane deck with metal guardrails, no shoulder, and no bike symbols painted on the ground - just the signs. It looks like the death trap that it is. So people see the often empty pedestrian sidewalk and go for it, only to feel like jerks when they do come across pedestrians. So thats some backstory. But I agree that bikes have no business in that narrow walkway. I myself have written the city asking that something be done; I personally feel that no bikes should be allowed up top, and signs would reflect this and direct all bikes to the lower level. The bike lanes that peter to nothing off of Pacific Hwy and NE Multnomah should be changed to direct riders to the lower level and remove the upper level as an option. There is almost no advantage to riding on the top level, and waiting for the occasional boat to pass is a small price to pay for such a great bike lane.