Not much detail, but I saw Hants County Council using stuff like you
describe about 4 years ago. They could pick villages of say x'000 people and
get the average time to get to A & E departments for example, with the
results both listed and as map overlays (in this case villages with time >
30 mins were circled).
For sure it would have been a paid-for service then, but it just proves it
has been there, been done.
