The Variety of American Grids

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The Variety of American Grids

by Daniel Nairn • May 31, 2010 9:54 am

I wanted a nerdy planning-related poster for my wall (other than the periodic table of city planning), so I made one this week. I scoured Google Earth and measured that quintessentially American grid in about a hundred downtowns around the country.

Of course, there are variations in block proportions within downtowns, but I tried to pick cities that had more uniformity than average to come up with a single prototype. (Washington, DC has very little uniformity.)

Click for the poster-quality version (large PDF).

Exploring these grid proportions messed with my preconceptions. I assumed the more western and newer cities would have larger grids than the more eastern and older cities, but no obvious pattern is discernible to me. Mobile, AL, settled by French colonists in the early 18th century, Tulsa, OK, a 19th century farming town, and Anchorage, AK, a 20th century frontier town, all share the same 300' x 300' internal block (street widths vary a little). What compelled the early settlers of these towns to choose, say, 220' over 440' lengths? I can't say I have any idea right now.

Manhattan is also a curious story. According to Witold Rybczynski, the expanding nation unequivocally chose the 1811 Commissioner's Grid of New York City over L'Enfant's baroque-influenced plan for Washington, DC as the model for new towns. While this is surely true, it begs the question: why are New York's long and skinny blocks not found anywhere else in the country? You would think at least one group of western settlers would seek to emulate their home town of New York more exactly.

I'm leaving aside the interesting value questions around block size. Ever since Jacobs, conventional wisdom has held that smaller blocks are preferable for walkability, but urban designer Fannis Grammenos challenges the grid somewhat in a Planetizen post.

Crossposted on Discovering Urbanism.

24 comments

Tags: street grids

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Daniel Nairn is a graduate student in Urban and Environmental Planning at the University of Virginia. He works, plays, and studies in Charlottesville. He also blogs at Discovering Urbanism.

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Interesting! I agree that there seems to be no discernible pattern as you travel from east to west across the country. Maybe the topography plays a role?

And NYC's blocks are indeed anomalous. The most confusing part to me is that unlike DC - where the houses are numbered 1-99 on the unit block, for example - the building numbers don't necessarily correspond to the cross streets. For me, DC is much easier to navigate because of that trait. I know that 900 G Street, NW will be at 9th and G!

by Emilyhaha on May 31, 2010 10:03 am • link • report

My understanding of NYC - can't provide a citation other than various classes and books over the years - is that the blocks are that shape because Manhattan itself is long and skinny, and cross-town street frontage does not have the same value as uptown street frontage. The elongated blocks maximize the frontage on the more valuable direction.

by David R. on May 31, 2010 10:35 am • link • report

Great poster, by the way!

by David R. on May 31, 2010 10:35 am • link • report

I understand you left D.C. off the poster because it's grid doesn't have the same degree of uniformity as the other cities. However for the sake of discussion in this GGW thread, what's the most common block size in DC?

by Paul on May 31, 2010 10:44 am • link • report

Nerdy indeed, but good nerdy.

(I bet someone has pointed this out already, but your Periodic Table has two "Re"s... maybe your Recycling Center should be Rc so as not to compete with Restaurant?)

by Graham S on May 31, 2010 11:08 am • link • report

Salt Lake City's large blocks and wide streets date back to the Mormon founders and their desire to create their Zion - each block is 10 acres in area, meant to support a family as a homestead with gardening and agriculture, with the wide streets providing ROW for irrigation ditches and also providing for wagon teams to turn around easily (i.e. without doing a 3-point turn).

These days, there are lots of interesting opportunities to develop alleys and mews within SLC's blocks, and the wide streets have proven to be a great resource for light rail.

by Alex B. on May 31, 2010 11:34 am • link • report

When speaking of New York are you talking about Manhattan, Queens, Bronx, Brooklyn, Staten Island or just Manhattan ?

If you are speaking of all parts that New York probably has every last type of grid in it except for how blocks are in Japan

by kk on May 31, 2010 11:35 am • link • report

I believe the Romans invented the grid system. How has it evolved over the centuries?

by Chuck Coleman on May 31, 2010 12:13 pm • link • report

Great graphic

One question - I realize that Macon owes its extra-wide streets to a lot of tree-lined divisions...but at 180ft wide, the Macon streets are essentially as wide as single blocks in Carson city.
A quick look at Google Maps shows that this is true for streets like Mulberry and 3rd - 2 parking lanes plus 2 traffic lanes in *each* direction plus a central divider! But that doesn't look to be representative for most streets...

by Bilsko on May 31, 2010 12:14 pm • link • report

@David R.: the blocks are that shape because Manhattan itself is long and skinny, and cross-town street frontage does not have the same value as uptown street frontage.

I would disagree with the latter thesis. Rather, I would say that because Manhattan is long and skinny, it needs much more uptown-downtown street capacity than crosstown street capacity, and so you have very wide avenues running uptown-downtown, which limits how many you can have. A few wide streets can carry more traffic than twice as many narrow streets. It's more about transportation planning than about the value of street frontage. Note that the Manhattan layout creates relatively more crosstown street frontage than frontage on the avenues, so something seems backwards about the thesis quoted above.

by David desJardins on May 31, 2010 4:38 pm • link • report

Detroit's blocks beyond the Woodward plan and ribbon farm influences are similar to Manhattan's long and skinny blocks for the most part--perhaps in part due to subdivision development through the years?

by Steve on May 31, 2010 7:24 pm • link • report

David and David, you're both wrong (but close). The reason for the Manhattan grid is that in the early 1800s, when it was being laid out, what mattered more than anything else was access to the waterfront. So there are TONS of streets going to the waterfront.

Wikipedia: "Each avenue was to be one hundred feet (30 m) wide. The avenues in the center of the island were to be separated by 922 feet (281 m), and the avenues along the waterfront were to be slightly closer. The operating theory was that street frontage near the piers would be more valuable than the landlocked interior, the waterfront being the location of commerce and industry of the time, and so it would be to everyone's benefit to place avenues closer together at the island's edges."

by Mike on May 31, 2010 9:53 pm • link • report

Aw. I was hoping you'd include an amorphous blob for Boston.

by andrew on Jun 1, 2010 11:29 am • link • report

The problem with the NY Avenues is they start at different places and don't travel up or down by 'blocks' for house numbers. The streets (above 14th) are all good, W and E on either side of 5th avenue, with 100 units per avenue (except broadway) and Madison and Lexington, which are 50 per because those were added later.

by Aaron on Jun 1, 2010 6:15 pm • link • report

San Francisco is an example of a grid with long narrow blocks similar to New York, especially around the Golden Gate Park Area. But there is not so much uniformity in the blocks. Some are more square.

by Scoot on Jun 2, 2010 6:39 pm • link • report

St. Louis has large swaths of unmodified blocks in the central corridor as long, and in many cases much longer than blocks in Manhattan.

by Matt on Jun 3, 2010 10:29 am • link • report

I did a little bit of this when trying new things for SimCity and found that my piddly little hometown of San Anselmo, CA made its four blocks downtown roughly the same dimensions as Manhattan's. I have no idea why that is, but at least one municipality tried it again. (If you want to look, they're along San Anselmo Avenue.)

by David on Jun 3, 2010 12:21 pm • link • report

This kind of study has been done before and is refreshing to see again.

Grids are fascinating at they are a layer over any given topography (e.g. San Francisco, San Pedro). Colliding grids make intersesting places (e.g. San Fernando Valley...City of Los Angeles, Burbank).

My favorite is the 200 foot block in Portland which is very pedestrian friendly. I've walked all over Carson City although it is an entirely different experience due to density more than street widths.

by StevenOwenPaige on Jun 4, 2010 12:00 pm • link • report

I suspect that there are as many reasons for a specific grid as there are grids. I would point out that the longer orientation of blocks in NYC (somewhat east-west but not always) is not limited to Manhattan and can not always be attributed to access to waterfront. The higher number of streets on the long side of the blocks have narrower rights-of-way would tend to reduce the amount of traffic on those streets. Less traffic would be more desirable for residential frontage. Remember that when the street system was designed it is not likely they were planning for the high-rise density of today. :)

There are also some wider rights-of-way along the longer side of blocks to handle higher traffic levels. The point being that this is not that different from residential subdivisions of today that are designed to keep traffic to a minimum. I can't prove that was the intent but it is logical and worth considering.

by Larry on Jun 4, 2010 1:13 pm • link • report

You should market this. It makes a great poster for planners

by MSplanner on Jun 4, 2010 4:55 pm • link • report

Very elegant poster!
Here in the Pacific Northwest we are true believers in the grid system.
Thanks for including Portland.

Thank you Graham for the catch on the Re element. The revised poster is
online at http://www.stephensplanning.com/media.html

by Ric Stephens on Jun 8, 2010 2:19 pm • link • report

Yea, in Chicago we think our "typical city block" is 660' x 330'. The area of the city you were looking in has a more legacy block structure than the typical city block. Very cool study though.

by Scott on Jun 24, 2010 8:53 pm • link • report

Allentown, Pa has an interesting grid system. Each full block is typically square but one named street runs north to south half way through the middle of each numbered block.

For example, in between 14th & 15th runs Madison, in between 15th and 16th runs Fulton, and so on. The locals call them "half streets" because they run mid block and are generally a bit smaller than numbered streets but they are in fact fully built out streets, not alleys. The city has the feeling of rectangular blocks but they are rally quite square as far as the post office is concerned.

by Joeseph on Feb 21, 2011 9:59 pm • link • report

Why are crosstown Manhattan streets wider at 14, 23, 34, 42 instead of, say, 10th, 20th, 30th, 40th...

by Sam Roberts on Mar 3, 2011 9:12 am • link • report