== NPOV == 

 This article touches on the advantages of curb extensions (sightlines for pedestrians etc) but there is no mention of the negatives.  Many exist such as reduced on-street parking, narrow roads (especially at junctions) force cars closer together increasing the risk of an accident.  No proof of this but it also makes driving seem more stressful.  Many schemes near me have been made too narrow for 2 buses to pass through together, hence causing a traffic backlog.  There is also a road in Fife, Scotland which is littered with these and when the parallel (fast) road was closed due to an accident all traffic had to use the "slow" road and large queues were caused by lorries/buses having to wait to pass the kerb extensions.