Why is this pole has has lock? It is a side walk supposedly used to block motor vehicles. https://ibb.co/S72wFDm?
It's so it can be removed by anyone who has the key, but not by anyone else. Maintenance gangs for instance, perhaps the gang tasked with repainting the makings and so on. They have them at a recycling area near here, they prevent anyone driving too close and endangering pedestrian users but are removed to allow the collecting truck access.
Been There, Done That.
It's a removable pole, so the lock keeps anyone from removing it without permission. If you have a lot of homeless (formerly known as BUMS) in the area, they would steal all those poles and take them to a recycling center. They also unscrew caps off of fire hydrants. Cities now have to replace those caps with plastic covers.
Just a removable pole. We have them in out parks, maintenence crews remove them so they can drive in with trucks/machines/mowers.
You are a good guy, so it may not occur to you, but those poles like that are great temptation to vandals. if they are not locked in place they are very likely to get thrown in the road, and cause a problem.if they are metal the may be stolen, but mostly it is to keep unauthorized people from changing things.
TO DRIVE SAFELY AND IT MONITORS EVERYTHING.
Could be poor engineering. On our street, the light poles were all installed and then the sidewalk crew came and poured the cement sidewalk around the poles. Goes on like that for several blocks