Oh, the wanderings of a curious mind.  As I was driving down a street a couple of days ago, I noticed that the speed limit was listed as 40 MPH.  I had this recollection that the speed limit was 35 on that road, when I was driving along the other side earlier in the day.  So suddenly I had this epiphany that maybe, just maybe, the speed limits on the two sides of the road were different?

A bit further down the road, the speed limit did go down to 35, so I figured that when I was driving up the opposite side, I probably just hadn’t noticed the change from 35 to 40.  However, it did get me thinking about this issue – do roads ever have different speed limits on opposing sides of the street?  Is there a requirement that they are the same?  I know that as humans we love congruency and symmetry, but is there a practical purpose to it?

As long as the speed limits do not vary greatly, I don’t see why they can’t be slightly different to account for differences in curvature and width of the road.  After all, sometimes one side allows for parked cars along the curb (and therefore should have a lower limit) whereas the other side may just have a wide shoulder not quite enough for a car (and therefore should have a higher limit).  When you’re winding up the side of a mountain on the inner lanes, the turns are much tighter than outer lanes.  Or even on freeways, perhaps there should be a 55 limit on the far right lane so it’s easier for cars to merge in and trucks can casually push on.  Then again, in a place like Los Angeles, who really follows those speed limits anyway?  :-/