The Measure of Things

I saw a sign last week on a lovely two-lane back road in rural Virginia.  It said “school bus stop 800 feet.”  It was a warning, I assume:   Careful!  There’s a school bus stop in 800 feet!  My brother and I were traveling at 55miles per hour which meant, if my story-problem math is right, that we would be at that spot in less than 10 seconds. But no one does that sort of math in their head while driving--and it took me more than 10 seconds to do it here-- besides, despite the well-known relationship between space and time, that’s not really how we think of distance.   As we hurtled along I looked up the road which was rising and falling the way old pre-interstates do, and I wondered when we would reach that magic place 800 feet ahead.  I wanted to fix my eyes on that spot, but there were no blocks or familiar markers to help me.  That we saw that sign a few more times gave me the chance to keep gnawing on the question, perhaps a little too much. 

On a two-lane state road it is impossible to visualize 800 feet, particularly when one is in motion.  On a city street, however, it is easy to visualize 4 blocks. Where’s the school bus stop?  It’s about 2 ½ blocks.  In Old Town Alexandria, that would be about 800 feet: in the east-west direction Old Town’s blocks are about 290 feet, so 2 ½ times that is 725’.  With that level of specificity one could not only find the bus stop but have a pretty good sense of what the walk there would be like.  With a street address one could be more precise, but that level of information is sufficient for the situation.  Even though every city has its own dimension of block—Washington’s are significantly bigger and more diverse than Alexandria’s, while Portland, Oregon, is known for its diminutive 220’ blocks—the block itself is a familiar and meaningful unit of urban measure.  

Technology can measure things with great precision, greater precision than necessary in fact, resulting in a quality of inappropriate specificity that I call “misprecision.”  Misprecision is precision out of context, lengths and strengths with no reasonable reference to human experience.  A computer-modeled construction detail dimensioned to 1/64^th of an inch is misprecision, as are clocks that count 10ths of seconds and nutrition guidelines described in grams.  Misprecision also describes exhausted units of measure that have long ago lost their referents.  What possible meaning does “horsepower” have to anyone now? I can easily picture a team of horses pulling a chariot behind them, but in what way does such a quadriga (a rare opportunity to use that word!) help anyone understand how fast a motorboat might go?  800 horses under the hood of a sports car?  That metaphor is OBT, overtaken by technology.  

It’s not that measurement isn’t important, or that we shouldn’t embrace new tools and technologies for measuring.  Big Data brings all sorts of previously disaggregated information into precise sets that can be overlaid and correlated, letting us describe—measure—cities and neighborhoods in fascinating and no doubt misprecise ways.  The question, I suppose, for urbanists is how much do we need to know and in what form to make lovable cities?  How do we communicate those qualities to constituents?  Is it more helpful to say that within a 1000 foot radius one can find food, drink, and conversation or that I can find all that in 3 or 4 blocks in any direction? No one navigates the city on radii, and 1000 sounds like a lot.  But, 3 or 4 blocks?  Wow, that’s convenient!