Re: OT: Converting miles/km

Peter Moylan wrote on 9/22/2024 :

On 22/09/24 16:59, Aidan Kehoe wrote:

Ar an dara lá is fiche de mí Méan Fómhair, scríobh Hibou:

>

I think you've missed my point, which was that the system for
determining the speed limit is thoroughly unreliable, and not a
suitable basis for restrictors, or even alarms sounding in drivers'
ears.

>
Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and
changes the usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very
occasionally gets things wrong but is usually reliable, even on those
parts of the island afflicted by speed limits in MPH. So my reading
of things is from my own relevant experience rather than a journalist
driving clicks.

>
My car, which is 14 years old, doesn't have such a feature. Despite that
my GPS navigator manages to display the speed limit, except in places
where reception from satellites is blocked. I assume that the limits are
contained in map data. Why then would the car need to read roadside signs?

Map data is often incomplete.  I've had examples where my car has displayed the wrong speed limit from map data, and then corrects it when I manage to find a sign.
I've experienced very few errors with my car, the main examples being school speed limits which are, per California law as related by the driver's manual, only applicable when children are present on the sidewalks and in the crosswalks around the school.

OK, I'll concede that there are sometimes temporary limits in place
because of roadworks and so on, but that's the exceptional case.

Not at all exceptional in California on the freeways, although the location changes from time to time.
/dps
--
Trust, but verify.