[georgefrowny]

One wonders if you could prefabricate kerb ramps and drop them in, rather than (I assume) casting them in place.

Maybe they'd settle badly if vehicles drive over them, kick up in the opposite corners and become a trip hazard.

The UK mostly skirts this by using tarmac and paving slabs instead of concrete.

[AlexandrB]

I don't think there's a way to do this without casting something to connect the pre-fab to the surrounding concrete sidewalk. Like how do you precisely cut out the existing curb so the prefab just fits (including elevation/slope) without excessive gaps or something? And if you're pouring concrete anyway, might as well pour the curb itself.

[lstodd]

With prefabs you first dig up both road and sidewalk, set up pre-cut granite curbs (kerbs?) on a mild concrete foundation (negates sinking completely), then repour and repave sidewalk and road. Lasts many years in -20C winters +35C summers climate.

[bombcar]

Or make the asphalt "ride up" onto the sidewalk itself, so the complicated part is made of asphalt.

Likely this won't be terribly faster, and I did see the company near us using a machine that was building curb cuts directly.

[georgefrowny]

I looked up kerb cutting machines and it's interesting how much of the process is cutting through cast-in-place kerbs with special saws.

There are hardly any of these in the UK, for example, and kerbs are nearly always made of kerbstones that are sunk into the ground. They have their own problems with sinking when driven on, and I imagine frost heave in areas where the ground freezes seasonally. But it does mean that a dropped kerb installation is quite quick. Most dropped kerbs are simple tarmac ramps rather than concrete castings here.

[XorNot]

I wonder if you could just ignore ignore settlement by provisioning for hydraulic slab jacking instead?

Include a built channel for injecting hydraulic grout a few months later once the settlements happened to correct it out.

[bombcar]

The ones I saw didn't actually cut the curb - they had arms that held out the form and "built" them in place. I was surprised, as the still-recent but earlier curb cuts had very obvious examples of actual cuts. It was similar to this, perhaps https://www.curbmachines.com

[bruckie]

Very few sites are going to be flat or square. I suspect prefabbed parts mostly wouldn't fit without custom adapters around the edges.