Lesson 2 - Width

 

Streetcars are ubiquitous in Europe.  A lot of them use meter-gauge.

 

 

 

 

If the streetcar line uses meter-gauge, the car is about 1 ½ meters in width.  What does standard gauge look like? 

 

 

 

 

 

It’s pretty close to 1 ½ meters.  Let’s be a little bit more accurate now.  Any railroad engineer outside of the United States could tell you in the middle of night, without even being asked, that standard gauge is 1435 millimeters.  That is a very odd size.  Where does it come from?  The answer is probably from the Romans.  They were the ones who built the first roads.  The roads developed ruts into which all wagon wheels had to fit.  If you built a wagon whose axles didn’t fit into the ruts, its axles would break sooner or later.  So people designed and built “standard gauge” wagons.  That standard gauge was used for the first railroad, and after the introduction of the metric system, it became 1435 millimeters.  Maybe for the Roman measurement system that was a round number. 

 

So for our purposes, remember we want to “think metric,” standard gauge for horsedrawn carts, railroads and compact automobiles is about 1 ½ meters.  It is the width required for two people to sit comfortably next to each other.

 

In case you are interested, here are some more railway gauges:

 

Railway Gauges

mm 

Meter Gauge

1000

Japan (conventional network)

1067

San Francisco Cable Car

1067

Standard Gauge and high speed rail systems everywhere

1435

Toronto subway

1495

Former Soviet Union, Finland

1520

Spain (conventional network), Portugal

1668

San Francisco Bay Area Rapid Transit (BART)

1676

 

 

Now let’s look at some actual road signs.  International regulatory road signs are usually round to clearly separate their outward appearance from directional signs which may be rectangular or arrow shaped.  An important category of international regulatory road signs are:

 

Max-Signs:

 

Speed Limit: 100 km/h

 

Speed Limit: 80 km/h

 

In the United States, all international regulatory road signs have to be superimposed onto a white rectangle.  Many of them are really max-signs in disguise, e.g.

 

 

 

At this point we are comfortable with meter gauge and the “standard gauge” for horsedrawn carts, railroads and compact automobiles of about 1 ½ meters.  So now, this sign should make some sense to us:

 

 

This is one of its typical uses as part of a freeway construction sign.

 

It is the same thing as saying:

 

 

It is a very effective attention getter for anybody who knows how wide 2 meters are.  The 2-meter-lane sign wears a lot of different hats.  The speed limit when entering the construction zone is usually 60 km/h.  It is increased to 80 km/h downstream after drivers have adapted to the smaller lane width.  More about speeds later.

 

The yellow markers, only used in construction zones, have precendence over the white ones.  Notice the left lane is only about half the width of a regular freeway lane.  The other half of that lane is used for the left lane of the opposing traffic.

 

 

 

By now we know that we’ll always fit through a standard door that is about 2 meters high and our subcompact sedan will always be able to use a 2-meter-lane (if the driver is up for it).  Our automobile is not taller than we are, so we’ll never have to worry about vertical clearance signs that indicate anything bigger than 2 meters.

 

We can ignore any of following.  All we ever have to think about is the big 2…

 

 

 

 

3.9 m vertical clearance 550 m after turning right.

 

 

 

And we’ll even fit into this underground parking structure.

A few  Points of Reference

 

Your height is probably no greater than

2 m

The height of your compact sedan is probably no greater than

2 m

The width of your compact sedan is probably no greater than

2 m

 

 

thinkMetric.com
Alfrediquelle 2
D-45127 Essen (Ruhr)
Germany

 

 

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