Don’t look in the trunk, it’s imperial in there

By The Metric Maven

Bulldog “Moon Landing” Edition

When I finally purchased a GPS for my automobile, the impact it had on how I drove around my city was enormous. I also immediately set it for kilometers instead of miles. Within a few weeks I had a good idea how far 100, 200 and 500 meters is and about how far I could see was often about a kilometer. For the next few years I merrily drove multi-state road trips and local ones with the GPS piloting my excursions.

My father did not own a GPS at the time I purchased mine and was curious. At his request I brought it with us on an errand and we set it to find the address where an old family friend had lived at a nearby lake. It immediately told us to proceed 200 meters to a nearby stoplight. My father’s face contorted, and some very disapproving prose was uttered. I don’t recall what he said, but I do recall laughing out loud. Despite my father being “metrically challenged” the test trip went smoothly and we arrived at our destination.

Because I had not estimated drive times in metric before, I had to adapt. A useful benchmark in Ye Olde English is 60 miles per hour or a mile per minute. 40 miles is about 40 minutes. If I saw a road sign which stated it was 270 miles to a destination, I would have to multiply out integer values of 60 and figure the remainder. “Let’s see 240 miles is four hours and 30 left over is 30 more minutes. so four and one half hours.” I immediately realized I had lost the mile per minute guesstimate in metric, but hours were instantaneous to determine. A good guesstimate of an average speed is 100 Km/h Kph . So let’s suppose a kilometer marker states it’s 450 Km* to a destination, immediately we know it’s 4.5 hours. For short trips I know that 0.1 hour is six minutes. If it’s 10 Km to a destination it’s about six minutes, 25 Km is 15 minutes, 50 is 30 minutes and 75 is 45 minutes.

I happily continued my GPS guided metric motoring over the last few years without incident. Then, this last winter I had a disruption. It had been hovering about zero degrees Fahrenheit or about -18 Celsius outside. I went to my car and drove to a battery store on a side of town with which I’m unfamiliar but was straightforward to find. I needed to go to a market next, and wanted to take the most direct route. I fired up my GPS. There was just one problem, it had been so cold the battery went dead and reset the unit. I had to tell the unit I was in the US and other information. I could not find my stored addresses. I tried cycling the power. All my saved addresses re-appeared! Great! I selected the market and began driving. The GPS display indicated I needed to drive 7 Km and make a right turn onto an interstate highway. I thought to myself “that’s not too far.” It seemed like it took quite a while to cover the 7 Km, but I took no real notice. When the turnoff onto an interstate highway arrived, the voice instructed me to “turn right in 0.4 miles.” Suddenly I had no idea how far that was. Even though I could see the turnoff, it bothered me I had no correlation with distance. As I entered the highway I was told to drive 7 miles. When I approached the off ramp to the secondary street leading to the market it again gave the distance in tenths of miles. They had no meaning for me.

I was completely familiar with this road and the turnoffs in metric, but the correlation with the Olde English distances on my GPS were giving me a sort of unexpected vertigo. As I approached the market I looked up at the distance display and all I could read was 600. I was so used to seeing meters there that my mind rejected what it was seeing. I thought it can’t be yards, they’re like meters, it must be feet. When I pulled into the parking lot I could barely read a tiny ft stacked up on the GPS units after the number. But it had been tenths of miles previously when I was turning. When did the units switch?

Driving with my GPS set to kilometers caused me to pay little attention to the distances on signs. Without metric for a touchstone, the craziness of US road signs became stark. I noticed this sign which indicates the left lane will end in 1/2 mile. You will note there is a second follow-up warning sign, which can be seen along with the first but not read:

This Lane Ends 1/2 Mile (note the second warning sign in the distance)

Here is the second warning sign in the distance:

This Lane Ends in 1000 feet

The first sign tells me that the left lane ends in 1/2 mile or 5280 feet/2 which is 2640 feet. The second sign, whose presence is clearly seen from the first, next tells us the left lane ends in 1000 feet, which is of course 1000 ft/5280 ft/mile or 0.19 miles approximately. Wow! How had I not noticed this crazy set of signs before?—oh—I was using metric with my GPS and ignoring them. If they had been in metric the first sign might have said: This Lane Ends in 800 meters, the second sign could then say This Lane Ends In 300 meters. This is much easier to read than 0.8 Km and 0.3 Km. Nice Naughtin friendly integers, and the same units for both signs.

One never hears cries of the “implied precision fallacy” when feet are used in a context like this. In this case the first sign is in miles, the second is in feet. This is a ratio of 1:5280. Where are the cries that feet are too small of a unit?—they imply too much precision for this usage—or that miles are too large? In the case of kilometers and meters, the ratio is only 1:1000.

When I returned from shopping, I set my GPS unit back to kilometers. As soon as I heard proceed 500 meters and take a left, I was calm again. As I drove home I noticed something else. I had not been looking at the distances on the road signs as my GPS provided distances to exits in metric. Apparently, when I was looking at the signs, I had been just noticing the road name and the exit numbers. With the interruption of my GPS unit still firmly in my mind, I realized that the road signs all had fractional distances. Harlan street 3/4 mile, or Jessman Drive 1/2 mile, yet the GPS would output decimal miles—-0.75 miles or 0.5 miles—-it did not match the fractional expression on the signs. This was but one more reminder that we have not even fully embraced decimals in this country, let alone the metric system. No wonder it seemed so odd.

Once I used a GPS with metric measurement, I embraced a system which has a dimensional continuum. I understood meters, and if I was told it was 1000 meters to a destination (which it has) or alternatively 1 kilometer, this created no distance discontinuity in my mind. They both cognitively registered as the same distance without distraction. Metric forms a continuous expression of sizes. When using Ye Olde English/USC/ACSOWM one may choose whatever unit you feel like, in fact we are encouraged to do this by our grade school pedants, but this farrago of units creates discontinuities in cognitive quantity comprehension. The sudden change from tenths of miles to hundreds of feet was a jolt. I was so happy I had my meters back. Olde English has hundreds of units from which one can choose. A false maxim of The Ye Olde English Arbitrary Grouping of Weights and Measures, is to choose a unit that fits the closest to what you’re measuring. This multi-card measurement monte encouraged massive unit proliferation, which in turn allows massive opportunities for fraud and confusion.

The metric system has but one base unit for length, the meter. The prefixes describe units which are multiplied or divided by 1000. The length of an object falls on the metric measurement continuum. If its length is near a prefix boundary, Naughtin’s Laws help to keep one’s intuition of magnitude continuous by smoothing out discontinuities. (This is also a reason I’m against the use of centimeters, and believe they should be discontinued for actual computation)

I had an unexpected realization from my GPS reset. Suppose you were from another country—ok any other country sans Liberia and Myanmar, and visited the US. You have been brought up on the metric system, and suddenly you are confronted with US roadsigns. You first must contend with miles, and signs with fractions of miles, not decimals. Then you suddenly encounter a sign that says: Right lane ends 500 feet. We switched units on you from miles to feet, and possibly even yards. You have no idea if that is near or far as the base unit of length has been changed–radically. One can see how this switching of units could cause panic, measurement vertigo, and uncertainty for a visiting driver. I had somewhat experienced their possible confusion when my GPS reset itself to Ye Olde English—and I grew up in this country.

Unfortunately our provincial culture does not seem to allow us to understand the potential confusion our jumble of units could cause a visitor from another country. The few who do try to accommodate visitors find it tough going. In 1982 the state of Florida decided to add metric units to its highway signs. The rationale behind this change was that over five million tourists visited Florida and many of them were unfamiliar with Olde English units. They also believed it would encourage Americans to become more familiar with metric units. Florida was going to use its own funds to implement this change. There was only one thing they needed, the approval of the Federal Highway Administration (FHWA).

It came as a surprise, when, despite the 1866 federal law which does not allow the prohibition of metric units in the US, the FHWA refused to allow the signs. They argued that Congress had passed a law which prohibited the installation of solely metric highway signs using Federal funds, unless Congress approved. The installation of these signs would violate neither of those conditions. The FHWA would later reverse itself without providing rational reasons for the attempted ban, or why it changed its stand. Like most tales of metric in the US, a later Florida Governor would refuse to allow the signs to be installed.

After my experience losing metric in my GPS, I can truly say to visitors to this country who must drive our roads, I feel your pain.

* Yes I’m using capital K deliberately.

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