Traffic calming is usually more expensive than speed cameras. A speed bump isn't expensive but people are usually talking about stuff like bump outs and raised intersections and protected bicycle lanes and wide sidewalks when they are talking about traffic calming. Those are six figures per intersection. Cameras are low five figures.

Traffic calming can be literally some poles or some pots with plants in them. It's the cheapest form of "infrastructure" after paint.

And you can make a traffic camera with a Raspberry Pi. It could be as cheap as a planter. It's the bureaucracy that makes it expensive.

PS plants are expensive, they need very regular maintenance.

Or you can let the plants dry out, the infrastructure is actually the huge and heavy pot :-))