Shared spaces only work if all users have equal access and respect the mobility of other users. By not providing space on the road engineers force a hierarchy of users. Larger higher speed vehicles end up with priority by default. Discretionary cyclists take the lane, docile cyclists use the available space on the periphery at the expense of their safety and discreet cyclists skip cycling in favor of recreation. Engineers in turn end up with expectation to the road for drivers which feeds demand.
What have engineers done to design in access and respect?