On Tue, 12 Feb 2008 05:02:55 -0800 (PST), Mizter T
wrote:

I've never really used a sat-nav system to compare true speeds with
indicated speeds, so I've never really been aware of the difference
between the 'true' speed I've been travelling at as opposed to the
'indicated' speed.

Be careful if you do use a sat-nav. If you're going up or downhill,
it will read slower because (so far as the satellites can see) you've
slowed down because your speed has a vertical component as well.

I guess that implementing a very accurate vehicle speedometer system
is hard to do, so I wonder if most vehicle (and in particular car)
manufacturers design their speedometers "on the safe side", so as to
indicate a faster speed than the true speed - based on the rationale
that it's better for drivers to think they're going faster than they
are, rather than think they are going slower than they are?

Yes, as it's illegal for one to read even 1mph under, but may read up
to 5% (I think) over. Thus, they all read over.

Neil

--
Neil Williams
Put my first name before the at to reply.

On Tue, 12 Feb 2008, Neil Williams wrote:

On Tue, 12 Feb 2008 05:02:55 -0800 (PST), Mizter T
wrote:

I've never really used a sat-nav system to compare true speeds with
indicated speeds, so I've never really been aware of the difference
between the 'true' speed I've been travelling at as opposed to the
'indicated' speed.

Be careful if you do use a sat-nav. If you're going up or downhill,
it will read slower because (so far as the satellites can see) you've
slowed down because your speed has a vertical component as well.

Unless your box is using the height it's inseparably calculated in
determining your speed!

If it was, it could tell you the gradient you're climbing, too.

tom

--
No hay banda

At 23:19:40 on Tue, 12 Feb 2008 Tom Anderson opined:-

On Tue, 12 Feb 2008, Neil Williams wrote:

On Tue, 12 Feb 2008 05:02:55 -0800 (PST), Mizter T
wrote:

I've never really used a sat-nav system to compare true speeds with
indicated speeds, so I've never really been aware of the difference
between the 'true' speed I've been travelling at as opposed to the
'indicated' speed.

Be careful if you do use a sat-nav. If you're going up or downhill,
it will read slower because (so far as the satellites can see) you've
slowed down because your speed has a vertical component as well.

Unless your box is using the height it's inseparably calculated in
determining your speed!

If it was, it could tell you the gradient you're climbing, too.

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?
--
Thoss

thoss wrote:

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?

Tomtom.

At 11:33:59 on Wed, 13 Feb 2008 John Rowland opined:-

thoss wrote:

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?

Tomtom.


Thanks. I'll check them out.
--
Thoss

On Wed, Feb 13, 2008 at 09:39:38AM +0000, thoss wrote:

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?

Mine turns the speed display from white to red when I exceed it
(possibly when I exceed it by a certain amount, not sure). Trouble is,
it's *far* too small to even see what colour the text is without taking
my eyes off the road for longer than I want to. I've not found any way
of getting an audible warning out of it.

It does give audible warnings when I approach speed cameras. It warns
me even when I'm stuck in traffic and being overtaken by arthritic old
ladies in zimmer frames.

I use Tomtom on a Palm Treo 680, I presume that other Tomtoms are the
same.

--
David Cantrell | Official London Perl Mongers Bad Influence

Featu an incorrectly implemented bug

At 11:54:45 on Thu, 14 Feb 2008 David Cantrell opined:-

On Wed, Feb 13, 2008 at 09:39:38AM +0000, thoss wrote:

Since we're here talking sat-navs and speed limits, and since sat-navs
have maps, measure speeds and know about speed limits, are there any
which issue a warning when the local limit is being exceeded?

Mine turns the speed display from white to red when I exceed it
(possibly when I exceed it by a certain amount, not sure). Trouble is,
it's *far* too small to even see what colour the text is without taking
my eyes off the road for longer than I want to. I've not found any way
of getting an audible warning out of it.

It does give audible warnings when I approach speed cameras. It warns
me even when I'm stuck in traffic and being overtaken by arthritic old
ladies in zimmer frames.

I use Tomtom on a Palm Treo 680, I presume that other Tomtoms are the
same.

I was hoping for something with an audible warning.
--
Thoss

David Cantrell wrote:


I use Tomtom on a Palm Treo 680.
Mine turns the speed display from white to red when I exceed it
(possibly when I exceed it by a certain amount, not sure). Trouble
is, it's *far* too small to even see what colour the text is without
taking my eyes off the road for longer than I want to. I've not
found any way of getting an audible warning out of it.

Have you downloaded the latest software? My latest download introduced an
option under "Safety preferences" to choose a sound for when you go over the
speed limit. I've never actually tried it, though.

On Thu, Feb 14, 2008 at 12:13:05PM -0000, John Rowland wrote:

Have you downloaded the latest software? My latest download introduced an
option under "Safety preferences" to choose a sound for when you go over the
speed limit. I've never actually tried it, though.

Oh, cool, didn't know about that - thanks!

--
David Cantrell | Nth greatest programmer in the world

Irregular English:
you have anecdotes; they have data; I have proof

On Thu, Feb 14, 2008 at 12:13:05PM -0000, John Rowland wrote:
David Cantrell wrote:
I use Tomtom on a Palm Treo 680.
Mine turns the speed display from white to red when I exceed it
(possibly when I exceed it by a certain amount, not sure). Trouble
is, it's *far* too small to even see what colour the text is without
taking my eyes off the road for longer than I want to. I've not
found any way of getting an audible warning out of it.
Have you downloaded the latest software? My latest download introduced an
option under "Safety preferences" to choose a sound for when you go over the
speed limit. I've never actually tried it, though.

The self-update thingy seems to think that I do indeed have the latest
version. No such option though.

--
David Cantrell | Enforcer, South London Linguistic Massive

Featu an incorrectly implemented bug