[rjd]

Having growing up in a metric country and lived in Britain I must admit its very nice having 60miles per equalling 60 minutes of driving for long trips.

Being able to say "I'm 45 miles away from X I'll be there in 45 minutes" without having to do recalculate each time you pass a road sign makes trips all the more pleasant.

[lutusp]

The solution to that problem is simple -- drive at 60 KPH (37 MPH) instead of 60 MPH. :)

This would save gas too.

[meaty]

Actually it wouldn't in my Citroen C5. The fuel efficiency peaks precisely at 60mph/100kph. Something to do with the power transmission ratio.

I get 2.83l/100km or 83mpg in old money out of that if I don't drive like an asshat.

[lutusp]

Yes,okay, I've heard stories like this so I cannot discount them. I find it hard to believe that a car could deliver better gas mileage at 60 MPH than at 37 MPH, unless there was something very strange about the number of gears and how they related to road speeds.

But ... there it is. There really are such cars out there.

[meaty]

It's more down to the sorts of roads. If you're doing 37mph it's usually in residential areas and extra-urban areas. These are notoriously full of traffic lights, other cars and humans which result in braking regularly and therefore costly energy sucking acceleration. Also engines are usually have peak energy transfer from fuel to distance at certain speeds due to gearing, revs, torque etc. This is by design.

If you're doing 60mph, you're probably on a relatively obstruction free A-road where the only energy required is to offset friction to maintain speed. I have driven from London to Leeds (195 miles) with not one single change in speed (apart from to take a piss and get a Burger King at Leicester Forest services!)

Also roads are a hell of a lot smoother and have less friction in Europe compared to the US. That makes one hell of a difference!

For ref, my car is a 1.9l diesel as well. These Citroen engines are super-efficient which is why I own it. I also have low rolling resistance tyres which make a 2-5% difference.

American cars are poorly designed guzzlers usually, even the ones they ship to Europe.

[flyinRyan]

Or do 120 KPH and just cut the numbers in half.

[HCIdivision17]

This principle is likely the reason imperial units stick: they're fantastic for fast fractional math. For the same reason, it's easier to work with 360 degrees in a circle than 2*pi radians.

[pretoriusB]

>This principle is likely the reason imperial units stick: they're fantastic for fast fractional math.

As opposed to multiples of ten, in the metric system? Huh?

[panzagl]

Draw a line that's a third of a meter.

[ygra]

Do it with a fifth of a yard ;-)

[pretoriusB]

Like, 100/3 = 33 cm? That's supposed to be difficult?

Or do you mean that it's difficult to know how to draw a third of a meter?

Why, is drawing a line that's one meter, or one yard, or one foot any easier?

Without a measure I can't draw accurately any of them.

[ygra]

I guess they were referring to how a third of a yard would be a foot or 12 inches and that most people have an intuitive understanding of such common lengths. Also, because of the factors involved, “simple” fractions (e.g. ½, 1/3, ¼, ...) often end up at integral lengths.

But intuitive understanding of certain lengths is certainly not limited to the Imperial system. I frequently use A4 paper for measuring if I don't have a ruler at hand. I know the span between the tip of my thumb and pinky is pretty much 21 cm and so on. 8.2 inches probably wouldn't be much handier either.

[meaty]

This is quite convenient I'll agree but my satnav tells me how long it's going to take and bar traffic, it's quite accurate.