How serious someone is about urbanism based on the materials they use to protect people from vehicles. More serious means more permanence. And more damage to cars, with less notice. On a highway, if a pedestrian jaywalks, they get hurt. In a pedestrian zone, if a car drives, it gets hurt.
If it's a temporary (plastic) installation: cones < poles < barrels < portable safety barriers < traffic barriers.
Traffic cones are the stackable orange ones suitable for a few hours use. Poles are the taller ones you can leave out overnight. Barrels get used on highways, for blocking whole lanes. Portable Safety Barrier is a movable fence - no physical protection, but highly visible. Traffic barrier is a plastic jersey barrier, easy to move, but also capable of being filled with water to provide an actual physical barrier.
For permanent (concrete) installations: signage < paint < flex-post < swale curb < armadillos < full curb < planter < jersey barrier* < bollards < raised planters < stair blocks.
Signage is functionally worthless, as the "Share the Lane" signs demonstrate. Paint is meaningless without enforcement, as the abuse of bus, carpool and bike lanes readily demonstrates. Flex-posts are just road debris waiting to happen. Installation down the street from me is down 2 already. 25 MPH speed limit. They sit on top of a swale curb. Swale (mountable) curb is just tactile paint to an SUV. Armadillos promising - more damaging, less able to be damaged. Full curb is a serious barrier to preventing casual mis-use. Jersey barriers are designed to be relocated, and so are only sort of permanent. Bollards are like icebergs - most of them exists beneath the surface. 7-11 builds them for real, and they will stop a moving vehicle. Bell bollards are superior to pole bollards, but harbor bollards are superior to both. Counter-intuitively, the more likely a bollard is to damage a car, the more effective it is - it means that drivers have to look around and beware. Raised planters may have trees planted in them, but that doesn't require a foot thick concrete wall--it is security made pretty. Stair blocks the gold standard - are designed to prevent car ramming attacks by terrorists - they protect Federal Courthouses.
