Perhaps streetcar drivers should close their doors when people have finished entering/exiting?

On crowded downtown streets, there is often a line of cars trying to get past a slower moving/stopped streetcar. Most motorists and (maybe) most cyclists are sane enough not to want to run someone down. 

So if the "doors open" REALLY meant someone was about to get on or get off a streetcar, I suspect drivers would be a lot more respectful of the doors being open.