‘The Streetcar’ – 7 – Chicken or Egg: Shaping the future or following the past?

February 23rd, 2013

This is the seventh in an 8 part series on “The Streetcar”.

  1. Conceptual Flaws: civic boosters lead the charge
  2. Errors of Geometry: split one-ways are dumb
  3. The role of transportation in economic development
  4. Symbolic Transit
  5. On the back of branding
  6. Separate and Unequal: on therails of division
  7. Chicken or Egg: Shaping the future or following the past?
  8. A New and Highly Sarcastic Plan for Economic Development

The route of the streetcar  will be substantially less than efficient for the purposes of transportation. If, as it’s proponents say, it will encourage development along it’s route, then to the extent that it does so, it will stimulate development in a form that is itself structurally difficult to serve efficiently with transit. Rather than helping shape future development into an ideal form, it will reinforce unplanned patterns from the past and be less efficient in the long term than it could be. Since many people have talked about the streetcar “shaping development” and even creating “transit oriented development”, it’s important to think deeply about what transit oriented development would look like and whether the streetcar would move us toward it.

I’ll make a clear example to illustrate my point before I apply the principle to a more subtle reality. Here we have a regular gridded street pattern and some regularly placed transit stops crossing it on the diagonal.

a grid

Let’s say that right now the whole grid is developed pretty evenly with two story buildings and that denser development grows around the transit stops over the next few years. Here are some contour lines so you can visualize it:

grid with development visualized

Generated from some random numbers for each stop

This doesn’t really look so far fetched as a development pattern for a city. Places like St. Louis have a long stretched out development pattern that seems similar at first glance.

Aerial photo of St. Louis

St. Louis

But what would such a shape mean for transportation? The grid isn’t just decorative stripes crossing a flat surface. It’s a collection of rectangular barriers(buildings) lined up end to end with gaps(streets) in between them. Unless there’s a parking lot or a completely vacant parcel, you simply can’t cross a block diagonally. You have to follow the streets. If our transit line is underground, that isn’t a problem. Assuming there’s nothing else in the way, we could just take a straight line through each stop from end to end.

grid with development and transit line

1.6 miles in length

But let’s say that, like the streetcar would be, it isn’t underground and has to follow the streets. If we want to hit each stop, we’ll need to zig-zag.

grid with zig-zagging transit line

2.3 miles

Our little transit line here is starting to look a bit less reasonable. Pythagoras tells us this is actually a bit over 43% longer than the straight-line underground version. Further, there’s no way at all to make a shorter trip while we have to stick to the grid. Even if you were walking or riding a bike, there’s just no shorter trip to be made between any two stations. We can make a trip of the same distance that should be a bit faster, but it can’t be shorter. Both of the following possible routes are the exact same distance as our hypothetical transit line.

grid showing manhattan distance equality

This same feature is actually one of the reasons grids(or an approximation of them) are a truly great design for transportation. Because many paths are equivalent, traffic can be distributed very effectively if any one path gets blocked or clogged.

One thing classical geometry doesn’t account for is real-world intersections. Passing through an intersection can take a lot of time. Whether there are stop signs or traffic lights, you’re going to spend a significant amount of time not only waiting while stopped, but slowing down to stop and speeding back up again. Anyone who’s ridden a bicycle through Newport should be acutely aware of this. More important for our consideration though, turns can’t be taken at full speed even if you have a green light, so each turn adds time to the trip. Left turns particularly will slow us down. In fact, in an effort to save time and money, UPS apparently decided that their trucks would never turn left if they could avoid it.

So anyway, our transit line can be seen making a lot of left turns, right turns, and  passing through a lot of intersections. It will also go 43% further than is strictly necessary. The alternative of course was for the transit line to run parallel to one of the streets for all or most of it’s length. A line that was fully parallel to a street would eliminate 11 turns, 5 intersections and 30% of the total length from the route while going the same effective distance. Recall that we’re assuming even density across the whole area, so a similar line simply angled in a different direction would serve just as many people and would do so with significantly less effort. Our example route is the least efficient possible choice for a gridded street pattern. A route that makes the line fully parallel to a street would be the most efficient possible.

This isn’t true just for transit, but for all transportation. The development that occurred around our line is diagonally crossing the grid. Since more trips will originate and end in the denser areas(there are more people and things there), more trips will be crossing the grid diagonally than would otherwise have done so. Bike travel, car travel, walking and transit would all be significantly less efficient in the long term because of the initial decision to build a stimulating line diagonally across the grid. On the other hand, there would be more reasonable paths to the average destination meaning that congestion could be better distributed if necessary.

Let’s express these ideas numerically so that we can compare reality more readily to our example. With the diagonal zig-zag, we go exactly as far in one direction of the grid as we do in the other. Let’s call this a ratio of 1/1. That’s the least efficient. If our line were to follow one street all the way, it would go the whole distance in one direction and none in the other. That would be 1/0, the most efficient. Where does the streetcar fall on that scale? It depends on whether you want to consider the extension to Vine street. Without it, the ratio is about 1/0.19:

Cincinnati Streetcar Map

With it, the ratio comes to about 1/0.28. Here’ I’m considering that the effective distance would be less(it doubles back) and that the route deviates back to the east again before leaving the grid.

Cincinnati Streetcar Map

That’s not awful. It’s not the worst possible route by this measure, but it’s 28% of the way to being the worst. If the streetcar simply went up and down Vine Street, as I’ve suggested it should for a number of other reasons, we’d see a ratio of 1/0, the most efficient configuration. Our measure of 1/0.28 can’t be written off as a case of reality being more messy than hypothesis. It’s a case of planners(or in this case, politicians) ignoring the euclidean realities of transportation in favour of sending some real-estate-speculation money more directly to established and popular constituents like Findlay Market.

The streetcar won’t be helping to shape the city into a form that’s easy to serve by transit. Transit and transportation generally is best able to serve people when they establish linear development patterns that follow reasonably good transportation corridors. The typical picture we see in the media of “transit oriented development” does little to consider this aspect of meta-orientation. It matters little if your cafe fronts the street if the street is out of the way of the transit line. Conversely of course, it matters little if the transit line goes right past you if you’ve got a fenced parking lot in front of your building. “Transit oriented development” needs to consider not only it’s human-scale orientation to the street, but it’s regional-scale orientation to major transportation corridors, including the orientation of gridded street patterns.

I don’t want to be misunderstood as implying that the streetcar is doing especially poorly here. There really aren’t any transit lines that take an ideal route through downtown at the moment, and they all certainly miss a lot of opportunities for redundancy and centrality that could by now have established a few major high density corridors branching off from Downtown if we’d let them. These opportunities were missed at some point and SORTA’s downtown/OTR routing is currently a giant mess.

SORTA downtown transit map

Spaghetti with red and blue sauce.

No, I make these points not because I think the streetcar will actually make transportation substantially more difficult. I make them to point out internal consistencies in the arguments used to justify the streetcar. If as proponents said the streetcar would indeed encourage a lot of “transit oriented development”, it wouldn’t do so very well, and it wouldn’t do so in a way that’s in the best possible long-term interest of a city that wants to move toward increasing transit use. If we want that, we really need to develop linear corridors with redundant high-frequency transit lines that try not to cross grids on the diagonal.

I want to conclude by assuring you that I’m not just pulling this out of my ass. Linear developments that parallel street grids are absolutely everywhere that there are grids. If anyone can find me a truly non-parallel yet still linear business district or other denser development pattern occurring in a fully gridded context I’d like to see it. Here are some examples of my own, pulled pretty randomly from satellite photos:

Aerial photo of St. Louis

Downtown St. Louis. It does follow the grid.

aerial photo of chicago


Aerial photo of chicago

Chicago again…notice that even though dense development is crossing the grid, it effectively has an “underground” line because the diagonal street breaks the grid and allows linear access.

Aerial photo of Toronto ontario


Los Angeles business district development

Los Angeles

Go do a little Google Earth exploring yourself and think about why Cincinnati wants to build a project, ostensibly to encourage development, that would violate this almost universal transportation oriented development pattern.

7 responses to “‘The Streetcar’ – 7 – Chicken or Egg: Shaping the future or following the past?”

  1. It seems like you’re relying on several major assumptions in this post to make your point valid.

    1) That all points are arranged along a single, linear path. This is not the case for Cincinnati’s central business district or Over-the-Rhine. In addition to Vine Street, Race Street, Walnut Street and Main Street also serve as major north/south destination corridors in addition to the many more east/west destination corridors. As a result, picking just Vine Street would limit the potential destinations and would potentially cause harm to those non-Vine Street corridors due to the preferential treatment shown to Vine Street.

    2) That all modes of transportation travel, or even desire to travel, along the most logical path. While this may be true in some instances, we know that humans are incredibly unpredictable and illogical. This is even more so the case in dense urban environments, which is why we see that cities built prior to the advent of the automobile follow non-grid forms. Since streetcars serve as urban circulators, they’re much more akin to the less logical patterns of pedestrians than they are the more logical patterns of cars. Case in point, show me where the logical linear path is located in these satellite images I pulled from Google Earth – Seville http://bit.ly/15blrzQ; Birmingham http://bit.ly/YLEfBw; Ankara http://bit.ly/YOtxJa; Jeonju http://bit.ly/15ElHZ7. The point is that the logical form of movement you’re talking about is not human influenced, it’s machine influenced.

    I would conclude by saying that not all forms of transit need to accomplish the same things…just as not all roadways need to accomplish the same things. Our cities should be building a diverse hierarchy of bus and rail transit that allow people to move around in a truly competitive form to the automobile. We need inter-city services, regional services, and neighborhood circulator services.

    • Nate Wessel says:

      @ Randy
      1. Yes! That’s a very good point. In my mind, Vine St and Main St are the two most important for transit to serve well in the short term. Both also seem to me like they might be a reasonably good place to center a transit corridor in the long term too. Serving both directly though necessarily means splitting service at least in half. I would argue that if preserving(or enhancing) access to both were our goal, perhaps a very high frequency corridor up and down Walnut might better do the job. Then maybe over time we’d develop a 3+ block wide denser and more commercial spine extending north out of the CBD rather than 2 thinner separate strips. To give you a better sense of where I’m coming from btw, my idea of “long-term” is at least 50 years out ;-)

      I think that even with Downtown, which is most obviously not linear(mound-shaped perhaps), the best places to encourage development *that is dependant on transit more than walking* are probably still in a line extending north-ish through OTR like in the above and west toward Price Hill. Walking-neighborhoods, like I might argue Downtown and OTR actually substantially are, are much more free from the importance of linearity.

      The basin itself is probably small enough and walkable enough that my point in this post is definitely a subtle one.

      2. Influenced by industrial age thinking or not, the grid isn’t likely to disappear in the next thousand years. So living inside the machine as we do, I think people’s organic meandering, at least while they’re motivated to reach a certain destination, is typically limited to the confines of a square drawn around their origin and destination. Any number of paths within it are equally ‘rational’ in the economic sense and it’s fun to mix it up. Still, there are many cases, probably most, where people just want to get wherever they’re going ASAP.

      …God, those cities are pretty. I really do need to get myself to Europe…

      (3). I found myself writing too much…this is going to be another post. Thanks for the great comment! You got me thinking :-)

  2. As always, my examples are largely anecdotal, and should be taken with a grain of salt… but, I think attempts to stimulate maximum growth via a straight linear transit line have their own shortcomings. One of the reasons I don’t care much for Columbus is that the majority of their food/dining/entertainment options seem to be on a single corridor. With High Street, they don’t have neighborhood entertainment districts… they have one long street. I love that in OTR, Main and Vine have totally different feels and identities — which the Washington Park area is developing, as well. It promotes a feeling of an entire, walkable neighborhood, where there is somewhere to go in almost any direction.

    To your point about a purely diagonal development route: that 2.3 mile zig-zagging route functionally becomes something approximating a direct diagonal route when one considers the slowing that comes with intersection. When traveling diagonally, one has the option to follow whichever direction has the walk light at an intersection. A friend living in CityWest has talked about how nice it is walking to a Reds game, because they can keep moving virtually the entire way there, never having to stop at a light. I park on Shillito Place for games, and do the same. As I walk, I know that there are places to stop and grab something to eat in any direction, should I so desire.

    • Nate Wessel says:

      I do the same thing with walk lights. I actually love living in a strongly gridded part of town(Pendelton) and I don’t think I’d trade it for anything. I get bored going in long straight lines like I have to do when I want to catch the bus at 13th and Main 5 or 6 blocks from home.

      And High Street…I totally feel you there.

      But I still think that transit works best when serving and reinforcing distinctly linear development. Perhaps we can better think of the kind of less-than-linear development that I think most people want in OTR as the result of the overlap of multiple modes, walking most prominently. As Randy pointed out above, walking alone tends to result in round, somewhat evenly distributed patterns like in Europe. OTR certainly originated as a walking neighborhood, and I think to a large extent it still is a walking neighborhood. The walkers will stimulate their own development patterns at the same time that transit passing through the same place stimulates a straight corridor. The result could be a very satisfying mix of the two and hopefully people would locate in the right places…so maybe sleepy little cafes would spring up off the main line in ‘walker territory’, and something like a grocery store where many people would need to carry heavy bags and get home quickly would pop up right next to a transit stop.

      While it’s written in the example in the post, the graphic doesn’t make it clear. I assumed we start with some evenly distributed two-storey development(walking type development), and that a transit line overlays on top of that. Every part of that grid would still be perfectly pleasant to walk but linearity would still work best for the transit line.

      Actually, I realize now that I didn’t properly account for the effects of walking in my projected development. Assuming some people would walk, we’d see something more like a square form around the diagonal transit-line-caused density diminishing from the most dense next to the line to the least dense in a far corner.

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