UK-style chevron signage in US

[conekicker]

The term of art for what the OP calls "chevron signs" (not to be confused with curve chevrons, which are also used in Britain, or the chevron pattern on roundabout aprons, which in Britain has the standing of a traffic sign in its own right) is "flag sign."

Indeed. I was expecting this thread to be about these kind of signs, not flag signs.

I hadn't considered the painted brick markings on some roundabouts (also note the use of what JNW calls 'curve chevrons' - which knowing him will be the correct term - many, or even most-but-not-all, roundabouts have those).

The block paving markings are these:

http://assets.dft.gov.uk/publications/traffic-signs-working-drawings/warningp500series/2sharpdeviationofrouteat4508.pdf

Colloquially known as "Oxford collars" as they were first used in Oxford, (or Oxford was one of the first places they were installed). The block paving is also expensive in comparison to a strip of grass! They also look unsightly if not maintained - weed growth - and the reflective finish (if applied) to the white blocks can wear quite quickly. They aren't that common as most roundabouts are adequately served by the Diagram 606 sign.

http://assets.dft.gov.uk/publications/traffic-signs-working-drawings/regulatoryp600series/p606turnleftandvariants.pdf

Although you often see chevron boards (Diagram 515) below the 606, it's not compulsory.

http://assets.dft.gov.uk/publications/traffic-signs-working-drawings/warningp500series/p515sharpdeviationofroute.pdf

Use of 515 is occasionally overdone  :

https://maps.google.co.uk/maps?hl=en&ll=53.422126,-1.412086&spn=0.001646,0.005198&t=h&z=18&layer=c&cbll=53.422449,-1.412043&panoid=XkUqXZBt7TUma8vo1XT0nw&cbp=12,117.51,,0,14.21