Why Don’t the Sidewalks Line Up?

I was running through Kirkland the other day and stumbled through an awkward placing of sidewalk ramps at a street crossing (NE 80th St and 131 Ave NE).  I went back later to figure out what was going on, and here is what I saw:

Kirkland appears to be changing to use more directional curb cutouts rather than a slope down to a single centralized one.  Here’s the old sidewalk, at least until Google updates the image:

I took the double stroller to test it.  At least the sidewalk is wide enough to make the turn, but it’s kind of annoying that there’s such a sharp turn at all.

They’ve also added a cutout on the other side of 80th (so to the right in the above photos), and here is what that crossing looks like:

But note again that the cutout, including the textured surface for the blind or visually impaired, doesn’t point in the right direction!  (I then spent a day paying attention to these textured surfaces and it seems to be standard practice for them to point in random directions.)  So what’s going on?  It appears that this is simply another problem caused by having large turning radii for vehicle turns.  Using a high-tech diagram:


In the left diagram we have a large turning radius for the roadway.  The desire line for pedestrians would be the straight line continuing the sidewalk – “A”.  This, of course, has a quite large crossing distance, and a curb cut would be almost 90 degrees off of the correct direction.  The shortest crossing distance, which would be perfectly aligned with a curb cut, would be “C”.  However, this is also the largest deviation from the straight-line path.  Worse, it would make pedestrians less visible, and since the curve encourages high speeds, it might be quite dangerous.  So in the end the design is forced to compromise with something like “B”.  In the right diagram with a tiny turning radius, the desire line has the shortest crossing distance and gets a properly aimed curb cut.

As another demonstration of the crossing distance, in the crossing of 80th there is almost an entire lane of distance in the road before actually reaching the travel lane.  Part of this is the bike lane, but part is due to the sweeping curve for the turn.

Just down the street (NE 80th St and 131 Ave NE), there’s another bizarre example:

Here they put a single curb cut at 45 degrees from the sidewalk.  This splits the distance between the crossings to the east (towards the camera) and the north (to the right in the picture).  However, they didn’t bother to put a crosswalk to the north, and they certainly didn’t put one diagonally across the intersection.  Then they used a ramp approach on the side with no crosswalk and a full curb blocking the walking path on the crosswalk side!  In the end, the travel path is mostly straight, but (coming towards the camera) involves turns to the right, left, and right and care to not clip a stroller wheel on the curb.

Even better, these are both within a few blocks of an elementary school.


3 thoughts on “Why Don’t the Sidewalks Line Up?

  1. It took me a while before I figured out that you were talking about the turning radius of the street and not the turn from the sidewalk onto the ramp. But now that I understand your complaint, it’s an interestng difference between the streets in my old NJ suburb and what Kirkland has.

    Thank god fire trucks will be able to take the turn at full speed, though!


    • Thanks; I added a few words to try to make that more obvious.

      Indeed. I don’t have any links handy, but it’s interesting that studies are starting to claim that overbuilt emergency vehicle access is a net loss for public safety.


      • Yes but at least the emergency vehicles will be able to speed to the collision sites of all the cars that can also speed.

        Why would anyone think this could end up being a safety issue?


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s