> Speed bumps (also called traffic thresholds, speed breakers or sleeping policemen) are a class of traffic calming devices that use vertical deflection to slow motor-vehicle traffic in order to improve safety conditions
1. Potholes are also being phased out in many locations, but apparently not on El Camino.
2. Horizontal deflection and blocking access (usually requiring more distance to be covered) both increase maintenance on vehicles; by my count, three out of four categories of traffic calming increase maintenance on vehicles --- it's clearly an allowed part of the design. Going back several comments, blocking access often makes cycling much worse too. As can narrowing, depending on how its done.
The vast majority of measures on the list I linked do not increase maintenance at all, and certainly don't cause a "lot more in vehicle maintenance". Some, like a roundabout, may cause driver to spend less in maintenance vs. alternative intersection designs.
How do you want to count? By category, I see 3 out of 4 categories that increase vehicle maintenance costs; some more than others.
By individual items: there's 6 items in narrowing, which I think is reasonable to say don't increase maintenance. There's 8 vertical deflections, which are all increasing. There's three in horizontal deflection, I'll give you roundabouts (I've argued enough about those elsewhere), so that's 2 more increasing and 1 not. For blocking, there's four, all of which are likely to increase travel distance.
So 6 + 1 = 7 vs 8 + 2 + 4 = 14. 7 out of 21 is the vast majority?
Pot holes clearly fit under vertical and horizontal deflection. Possibly block or restrict access. Deferred maintenance could be a general category of traffic calming.
Gentle vertical and horizontal deflections do not put undue wear on a car. This is why it is okay for roads to have things like turns. When cars go around roundabouts, through residential chicanes, or over properly designed speed humps at reasonable speeds, it does not put any more wear on a car than normal road features.
Speed bumps are relatively gradual changes in height relative to pot holes. A properly built speed bump driven over at an appropriate speed doesn't "shock" your vehicle.
> Speed bumps (also called traffic thresholds, speed breakers or sleeping policemen) are a class of traffic calming devices that use vertical deflection to slow motor-vehicle traffic in order to improve safety conditions
It's just a difference of degree of deflection.