The sharrows markers on the road here clearly show that bikes are allowed to take the lane when traveling these few blocks between the bikes lanes of Pine/Spruce and the bike lanes across the South St bridge, the principal route for many bicycle commuters to/from Center City and West Philadelphia.
I've had many issues of cars driving aggressively to bicycles taking the lane, with drivers impatiently revving engines and warning bicyclists to get over to allow them to pass (along roads that have cars parked on both sides, thus forcing bicyclists into potential dooring situations).
Better education is needed to inform both drivers and bicyclists on the use of sharrows. Perhaps additional "Share the road" signs?
I even had drivers yell at me that "sharing the road" means I have to move over when they want to pass, a very impolite and rude gesture to someone who is just trying to bike to/from work safely.