I rarely visit this Topic, but the title caught my eye and reminded me of a pet peeve with our GPS (your Sat Nav's) units here in the U.S.
Seems, the manufacturers believe that a female voice with a pronounced British (English?) accent will be the most aggravating method of grabbing one's attention. This is especially true when you've made an arror and haven't turned were the 'magic magenta line' leads... "RE-calculating" is, at once, condecending, superior and mother-in-law like...
As to roundabouts...as jno stated they have been in use for years in the New England states... saw my first in Boston. We are now seeing them here in the western, predominantly rural, U.S.
Thankfully, the ones near here are all single lane. The multi-lane ones in New England are accidents waiting for a time to happen. I'm sure they were invented by insurance appraisers.... (somewhat akin to Marmite... so many people say it's really great stuff, all the while it's quietly waiting in it's small perfunctory brown jar to attack your mouth with vileness personified... gasp, gurgle... spit... spit!