Metrication

[1995hoo]

They already tried having the same speed limit in every state. It failed miserably and it was a stupid law. It makes eminent sense that a flat, empty state like Illinois Kansas should be free to set a higher maximum than a place like Connecticut.

[Poiponen13]

How do Americans measure things that are measured in micro-, nano-, or picometers? At least rainfall measured in inches creates ridiculously small values, because inch is the smallest commonly used unit.

[MikeTheActuary]

How do Americans measure things that are measured in micro-, nano-, or picometers?

We use micro-, nano-, or picometers as appropriate.   Fields where we need such small units of measurement are standardized on SI with the rest of the world.

That being said, in US customary measurements, 1 inch = 12 picas; 1 pica = 6 points; 1 point = 20 twips; and 1 inch = 1000 mils.  I've seen points and picas used in reference to typography, but otherwise....

At least rainfall measured in inches creates ridiculously small values, because inch is the smallest commonly used unit.

0.1 inches = 2.54mm.   I don't believe there's anything to be gained by attempting to measure in a more granular level of detail, given the limitations of measurement tools, and the potential variability of precipitation amounts.

[kalvado]

The maximum limit would be 150 km/h.

Do you realize that there aren't any roads in the US with that high of a speed limit today? Most places are equivalent of 120 kph or far less.

Don't let stupid engineering destroy beautiful round numbers!

[kkt]

How do Americans measure things that are measured in micro-, nano-, or picometers? At least rainfall measured in inches creates ridiculously small values, because inch is the smallest commonly used unit.

The need to measure things that small is relatively new.  U.S. customary units are used by the mass of people in common everyday situations, but for things that small now they're probably using SI for the engineering and manufacture.

Prior to the mid 1900s, engineering something like a ship or major bridge would probably have been done in 1/1000s of an inch.  For liquids, apocatharies had their own system of units, of which the smallest unit was the minim of approx. 61.6 microliters.  Medical doctors and pharmacists started switching from apocatharies' measure to metric in the 1950s, I believe.

https://en.wikipedia.org/wiki/Apothecaries'_system

[Scott5114]

Each state would decide if they have metric speed limits.

So none of the states would have metric speed limits?

[Road Hog]

Short anecdote alert appropos of perhaps little: My all-American Chevy requires a 17mm socket to do the rear brake calipers, a 13mm socket to do the front brakes and a 10mm to change the terminals on my battery. Hate to break it to all you Wankees, but "metrication" is here to stay, at least in the trades.

[kalvado]

Short anecdote alert appropos of perhaps little: My all-American Chevy requires a 17mm socket to do the rear brake calipers, a 13mm socket to do the front brakes and a 10mm to change the terminals on my battery. Hate to break it to all you Wankees, but "metrication" is here to stay, at least in the trades.

Once upon a time I needed a 9 mm wrench right now, asap, yes for real, no, I can't wait for next day delivery.
Now that ended up in 15 min drive to the only place in the area carrying such....

[Road Hog]

Short anecdote alert appropos of perhaps little: My all-American Chevy requires a 17mm socket to do the rear brake calipers, a 13mm socket to do the front brakes and a 10mm to change the terminals on my battery. Hate to break it to all you Wankees, but "metrication" is here to stay, at least in the trades.

Once upon a time I needed a 9 mm wrench right now, asap, yes for real, no, I can't wait for next day delivery.
Now that ended up in 15 min drive to the only place in the area carrying such....

Luckily most stores carrying tools have both SAE and metric. I can tell you Tractor Supply has both, so you're in luck with with other outlets.

[kalvado]

Short anecdote alert appropos of perhaps little: My all-American Chevy requires a 17mm socket to do the rear brake calipers, a 13mm socket to do the front brakes and a 10mm to change the terminals on my battery. Hate to break it to all you Wankees, but "metrication" is here to stay, at least in the trades.

Once upon a time I needed a 9 mm wrench right now, asap, yes for real, no, I can't wait for next day delivery.
Now that ended up in 15 min drive to the only place in the area carrying such....

Luckily most stores carrying tools have both SAE and metric. I can tell you Tractor Supply has both, so you're in luck with with other outlets.

8 and 10 mm, sure, any hardware store

[kkt]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

[Scott5114]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

[kkt]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

I-19 in Arizona for distance signs (but not speed limits)...

[kalvado]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

I-19 in Arizona for distance signs (but not speed limits)...

Laws are written in imperial units - and it would be difficult to enforce them across unit systems. Distance to the next city isnt legally binding, unlike speed limit

[Poiponen13]

I prefer measuring wind speed in m/s rather than km/h if metric is used. Km/h is for vehicle speed.

[kalvado]

I prefer measuring wind speed in m/s rather than km/h if metric is used. Km/h is for vehicle speed.

Oh, then maybe...
US should convert speed limits to m/s to avoid confusion with MPH!

[michravera]

I prefer measuring wind speed in m/s rather than km/h if metric is used. Km/h is for vehicle speed.

m/s is a base-derived velocity or speed. km/h is derived from two derived units. By the way 1 m/s is exactly 3.6 km/h. It may be that we tend to use km/h for vehicle speeds because they have a bigger value and thus, rounding of them to whole units FEELS more precise. One wonders why we think that 120 km/h feels more precise than 33.3 m/s, but many people do think that. That said, m/s is a quantity that is easier to estimate over short time periods. How many meters did I move in 10 seconds. Divide by 10. How many meters did I move in the last second? That's your answer. A speed trap actually measures reciprocal velocity (time divided by distance) and we compute the reciprocal, so that we are comfortable with the unit.  Most "speed measuring devices" actually COMPUTE the speed from observation of other effects (wheel spin rate, red shift, etc).

... and don't get me started on the fact that 98.6F is a fraud.

[MikeTheActuary]

I'm in a nitpicky mood.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

Well, there is this: https://www.google.com/maps/@44.9891819,-73.4572722,3a,75y,194.08h,91.77t/data=!3m6!1e1!3m4!1s96q5fzl6UcpCpHhbx92hpA!2e0!7i16384!8i8192?entry=ttu

Laws are written in imperial units - and it would be difficult to enforce them across unit systems. Distance to the next city isnt legally binding, unlike speed limit

Actually, when US laws don't invoke SI units, they invoke US Customary measures, rather than Imperial.

For statute miles and speed limits, US Customary and Imperial measures do match, but when you get to certain measures of volume or mass, the two systems do vary.

[kalvado]

I prefer measuring wind speed in m/s rather than km/h if metric is used. Km/h is for vehicle speed.

m/s is a base-derived velocity or speed. km/h is derived from two derived units. By the way 1 m/s is exactly 3.6 km/h. It may be that we tend to use km/h for vehicle speeds because they have a bigger value and thus, rounding of them to whole units FEELS more precise. One wonders why we think that 120 km/h feels more precise than 33.3 m/s, but many people do think that. That said, m/s is a quantity that is easier to estimate over short time periods. How many meters did I move in 10 seconds. Divide by 10. How many meters did I move in the last second? That's your answer. A speed trap actually measures reciprocal velocity (time divided by distance) and we compute the reciprocal, so that we are comfortable with the unit.  Most "speed measuring devices" actually COMPUTE the speed from observation of other effects (wheel spin rate, red shift, etc).

... and don't get me started on the fact that 98.6F is a fraud.

pretty much everything is measured indirectly..
With that - it's also about utility of the measurement. Trip distances are usually in miles/km range, few people would drive 0.1 mile or 100 m. And second is convenient for small intervals - but daily life is planned in hours and minutes. So planning a trip it makes sense to think about 150 miles or 240 km, not about 2.4e5 meters. And if that trip would take 2.5 hours that's OK. 9000 seconds is much less informative.
Short distance running, on the other hand, is in meters/yards, and seconds, maybe minutes. Because it makes sense. Marathon is again miles/km and hours...

[kkt]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

I-19 in Arizona for distance signs (but not speed limits)...

Laws are written in imperial units - and it would be difficult to enforce them across unit systems. Distance to the next city isnt legally binding, unlike speed limit

US customary units are defined in terms of SI units.  It would be a pretty longshot defense that they thought the speed limit in km/h was mph.

[GaryV]

... and don't get me started on the fact that 98.6F is a fraud.

And yet newspapers make the same type of conversion mistake over and over. There's a story about some business segment contributing 3B euros to the economy. And they helpfully translate it into USD for our convenience - carrying it out to 3 or 4 significant digits. Sigh.

[kalvado]

Each state would decide if they have metric speed limits. The limits would be same in every state. The maximum limit would be 150 km/h.

The U.S. is a very mobile society.  It would be really stupid for some states to have signs in miles and others in km.

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

No state ever used any of them.

I-19 in Arizona for distance signs (but not speed limits)...

Laws are written in imperial units - and it would be difficult to enforce them across unit systems. Distance to the next city isnt legally binding, unlike speed limit

US customary units are defined in terms of SI units.  It would be a pretty longshot defense that they thought the speed limit in km/h was mph.

OK, now add accuracy of police meter (1 MPH +1% per certificate), permissible speedometer error,  earth curvature,  and you better have a math professor on standby for court proceedings.

[J N Winkler]

That being said, the 2004 Standard Highway Signs book had a whole slate of metric signs, including for things like speed limits.

It never presented a complete design specification for freeway guide signs that used metric units, however.  All of the example illustrations in the "design guidelines" section used "MILES" (vertically centered on the numerical part) in distance expressions.  The very few guide sign example illustrations in SHS with metric units appeared elsewhere in the manual and suggested that FHWA expected the units part to be at the same size and on the same baseline as the number.

I-19 in Arizona for distance signs (but not speed limits)...

Yes, to designs that differed between 1981 (first installation of metric signs) and 1998 (replacement of the 1981 signs).  And although I know of no record that they were actually posted, the 1981 plans set has designs for metric speed limit and advisory speed signs similar to those later added to the 2003 MUTCD.  Speed limits were soft-converted (e.g., 88 km/h for 55 MPH).

[Brandon]

How do Americans measure things that are measured in micro-, nano-, or picometers? At least rainfall measured in inches creates ridiculously small values, because inch is the smallest commonly used unit.

It varies by what's being discussed, used, or sold.  If you're talking about distances, it's miles.  Height?  Feet and Inches.  Milk, water, and gasoline?  Gallons, especially for larger milk and water sizes, then quarts and pints.  Oil?  Quarts.  Weight?  Pounds.  A small chocolate bar?  Ounces.

[algorerhythms]

Height should be measured in light-nanoseconds.