# Miles Per Hour In England **URL:** \ **Category:** Factual Questions\ **Created:** [March 6, 2010, 4:32pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532 "2010-03-06T16:32:10Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [March 8, 2010, 7:52pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/41 "2010-03-08T19:52:17Z")
> [@Rayne\_Man](#): > > That’s irrelevant as all our road signs are still in miles. It’s not irrelevant as only a current show can represent current traffic signage. Anything old can only show what was relevant at the time. ---
**Author:** ![Rayne\_Man](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@Rayne\_Man](https://boards.straightdope.com/u/Rayne_Man)\ **Post date:** [March 8, 2010, 7:54pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/42 "2010-03-08T19:54:56Z")
> [@Harmonious\_Discord](#): > > It’s not irrelevant as only a current show can represent current traffic signage. Anything old can only show what was relevant at the time. But that signage is still relevant now. Things haven’t changed. ---
**Author:** ![WotNot](https://avatars.discourse-cdn.com/v4/letter/w/e19b73/32.png) [@WotNot](https://boards.straightdope.com/u/WotNot)\ **Post date:** [March 8, 2010, 7:55pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/43 "2010-03-08T19:55:45Z")
> [@Sunspace](#): > > YAlso, the Imperial pint has 20 fluid ounces, while the US pint has 16, so the Imperial fluid ounce is _smaller_ than the US fluid ounce. Though the Imperial pint is stlll larger than the US pint. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [March 8, 2010, 8:06pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/44 "2010-03-08T20:06:04Z")
> [@Rayne\_Man](#): > > But that signage is still relevant now. Things haven’t changed. You can’t know that without research which is what I consider this thread to be. ---
**Author:** ![Myrnalene](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@Myrnalene](https://boards.straightdope.com/u/Myrnalene)\ **Post date:** [March 8, 2010, 8:38pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/45 "2010-03-08T20:38:26Z")
> [@Harmonious\_Discord](#): > > You can’t know that without research which is what I consider this thread to be. A British person can’t tell us what British road signs look like without research? ---
**Author:** ![put\_down\_the\_sabre](https://avatars.discourse-cdn.com/v4/letter/p/da6949/32.png) [@put\_down\_the\_sabre](https://boards.straightdope.com/u/put_down_the_sabre)\ **Post date:** [March 8, 2010, 9:30pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/46 "2010-03-08T21:30:36Z")
> [@Myrnalene](#): > > A British person can’t tell us what British road signs look like without research? No, this thread constitutes research – asking British people. pdts ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [March 8, 2010, 10:31pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/47 "2010-03-08T22:31:04Z")
> [@Sunspace](#): > > Obligatory and usual nitpick: the US System of Customary Units is not the Imperial System. The volume units differ: 1 Imperial gallon (4.5 litres) is not 1 US gallon (3.8 litres). Also, the Imperial pint has 20 fluid ounces, while the US pint has 16, so the Imperial fluid ounce is _smaller_ than the US fluid ounce. [Comparison between the US and Imperial systems](http://en.wikipedia.org/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems) Gotta admit, even in the US when I order a pint, I _expect_ an Imperial pint, which is 19.2 US Oz. Luckily I only order pints in places that are likely to offer them, rather than the more common 12 oz, 16 oz, and 22- or 23 oz sizes. And the size difference between our ounces and Imperial ounces is negligible unless talking about a lot of ounces (1 us Oz = 1.04 UK Oz). What makes the British pint so much larger is that by definition, it’s 20 (UK) ounces. > [@](#): > > This becomes important when discussing gas mileage on the US/Canada border. L/100 km, miles per US gallon, or miles per Imperial gallon? No one on _our_ side of the border uses L/100 km. A lot of Ontarioians that I know still use mpg, but it’s obvious they’re talking about their gallons. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 8, 2010, 10:49pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/48 "2010-03-08T22:49:53Z")
From some quick Googling, it looks like the British fluid ounce is significantly closer to the “standard” of the volume of one weight-ounce of water than the US ounce is (though still about a fifth of a percent off). I wonder why we shifted the value of our ounce? And then, of course, with weight-ounces, you have to worry about whether they’re Avoirdupois or Troy, and there’s 16 Avoirdupois ounces in a pound, but only 12 Troy ounces in a Troy pound, so a pound of gold weighs less than a pound of feathers. ---
**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\ **Post date:** [March 11, 2010, 10:25pm UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/49 "2010-03-11T22:25:46Z")
> [@Chronos](#): > > From some quick Googling, it looks like the British fluid ounce is significantly closer to the “standard” of the volume of one weight-ounce of water than the US ounce is (though still about a fifth of a percent off). I wonder why we shifted the value of our ounce? You might not have done. The british have modernised their weights and measures over the last few hundred years. [QUOTE=wiki entry on the Gallon] In 1824, Britain adopted a close approximation to the ale gallon known as the Imperial gallon and abolished all other gallons in favour of it. Inspired by the kilogram-litre relationship, the Imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury and at a temperature of 62 °F. In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density 0.998859 g/mL weighed in air of density 0.001217 g/mL against weights of density 8.136 g/mL. This works out at approximately 4.5460903 L (277.4416 cu in). The metric definition of exactly 4.54609 cubic decimetres (also 4.54609 L after the litre was redefined in 1964, ≈ 277.419433 cu in) was adopted shortly afterwards in Canada; for several years, the conventional value of 4.546092 L was used in the United Kingdom, until the Canadian convention was adopted in 1985. [/QUOTE] ---
**Author:** ![bengangmo](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@bengangmo](https://boards.straightdope.com/u/bengangmo)\ **Post date:** [March 12, 2010, 2:12am UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/50 "2010-03-12T02:12:33Z")
> [@Markxxx](#): > > I have friends in NZ and they use metric, the only thing they never give in metric is weight. I have never heard any Kiwi refer to anything but “stone” to indicate their body weight. Of course that’s just people I know and they are all from Christchurch so it could be local +1 - although it is dying - and perhaps one of the biggest reasons is that our rugby players are now all referred to in kilos. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 12, 2010, 3:38am UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/51 "2010-03-12T03:38:25Z")
> [@Ximenean](#): > > We buy petrol (gasoline) in litres, but measure fuel consumption in miles per gallon. This seems unnecessarily complex. ---
**Author:** ![Ximenean](https://avatars.discourse-cdn.com/v4/letter/x/aca169/32.png) [@Ximenean](https://boards.straightdope.com/u/Ximenean)\ **Post date:** [March 12, 2010, 10:19am UTC](https://boards.straightdope.com/t/miles-per-hour-in-england/531532/52 "2010-03-12T10:19:29Z")
> [@kanicbird](#): > > This seems unnecessarily complex. Welcome to Britain :). Yes, it would be sensible to use miles per litre, but mpg is pretty ingrained. The alternative is the standard metric measurement, litres per 100km, which does appear in the small print of car advertisements. This has never caught on because (a) we don’t use km and (b) it works the other way round to what we are used to - in the L/100km system, lower numbers are better. [Previous page](https://boards.straightdope.com/t/miles-per-hour-in-england/531532.md?page=2)