The Washington, DC region is great >> and it can be greater.


America's most efficient city is... Miami?

DC may be tops when it comes to green roofs, but the region stands out less on a more impactful environmental indicator: how efficiently our infrastructure is laid out.

The purpose of infrastructure is to connect people, goods, information, and services. When people live close together, less infrastructure is needed to make these connections. Consider one type of infrastructure, perhaps the most representative from an urban planning perspective: roads.

Roads cost money to build and maintain. Movement along those roads creates pollution and costs the users time. All else equal, it is more efficient to build, use, and maintain fewer roads per person.

Which of the 12 statistical areas in the United States with more than 5 million inhabitants has the greatest number of people per mile of arterial roads? That honor goes to the Miami Metropolitan Area, perhaps not by choice but rather by geographic necessity, tightly bound by ocean to the east and the Everglades to the west.

Statistical area2010 populationMiles of primary roadPeople per road mile
Miami-Fort Lauderdale-Pompano Beach, FL Metro Area5,564,6351,4623,807
New York-Newark-Bridgeport, NY-NJ-CT-PA CSA22,085,6498,0602,740
San Jose-San Francisco-Oakland, CA CSA7,468,3902,9512,531
Chicago-Naperville-Michigan City, IL-IN-WI CSA9,686,0213,8382,524
Los Angeles-Long Beach-Riverside, CA CSA17,877,0067,6632,333
Washington-Baltimore-Northern Virginia, DC-MD-VA-WV CSA8,572,9713,9502,170
Philadelphia-Camden-Vineland, PA-NJ-DE-MD CSA6,533,6833,3491,951
Houston-Baytown-Huntsville, TX CSA6,051,3633,1271,935
Boston-Worcester-Manchester, MA-RI-NH CSA7,559,0604,2291,788
Detroit-Warren-Flint, MI CSA5,218,8523,0111,733
Dallas-Fort Worth, TX CSA6,731,3174,1271,631
Atlanta-Sandy Springs-Gainesville, GA-AL CSA5,618,4314,0481,388
Click on a column header to sort the table.

In contrast, the Atlanta Combined Statistical Area (CSA), the most sprawling of the 12 regions, has roughly the same population as Miami, but its roads total a distance nearly 3 times as long. Wouldn't it be great if we could spend all the money that goes to maintaining those unnecessary miles of road on something more productive?

The DC-Baltimore-Northern Virginia CSA ranks right in the middle, at number six, just behind Los Angeles, a fact that local environmentalists probably won't find especially comforting. At least we have both Houston and Dallas beat.

Miami is the only one of the largest metro areas not to have multiple Metropolitan Statistical Areas making up one larger CSA. Does that account for the change? No; even if you look at the individual Metropolitan and Micropolitan Statistical Areas that make up those 11 CSAs, Miami's still has the most people per road mile.

The gap between the Miami metro area and the second place, New York-Northern New Jersey-Long Island, NY-NJ-PA, is closer, and without Ventura County and the Inland Empire, the Los Angeles-Long Beach-Santa Ana, CA metro area jumps to #3, but otherwise little changes in the calculation.

Cross-posted at R.U. Seriousing Me?

Chris Dickersin-Prokopp spends his days in Anacostia and nights in Petworth. He studied Latin American Studies and Urban Planning. He runs the blog R.U. Seriousing Me? and occasionally contributes to the Washington City Paper


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Wouldn't lane-miles of arterial road, or just plain lane-miles of road, be a better measure than miles of road.

I suspect that Boston would rank much higher if you looked at lane-miles instead of miles of highway. They have much fewer of the six- and eight-lane arterial roads that predominate in our suburbs.

by Ben Ross on Apr 15, 2013 11:38 am • linkreport

Is a CSA really a good border to use to compare areas in this fashion?

It seems kind of arbitrary. Wouldn't MSAs make a bit more sense?

by andrew on Apr 15, 2013 11:44 am • linkreport

Since when is infrastructure equal to miles of roads? Why not include rail roads, bike lanes, pedestrian paths? Or even the number of bridges? A quick count shows that 8 of these 12, including the entire top 3, are cities dissected by significant water bodies, be it a river, a bay or the ocean.

by Jasper on Apr 15, 2013 11:46 am • linkreport

Seems like geography is a factor in the top 6 at least. Every city before DC is also on the coast. We (and Houston) don't have the same constraints until you're well close to the edge of our respective CSAs.

LA has the ocean one side and then most of the area you see in the picture is a lot of arid desert/mountains on the other.

by drumz on Apr 15, 2013 11:48 am • linkreport

Boston is an outlier to what I said however since it's very close to the coast but lower on the list.

by drumz on Apr 15, 2013 11:50 am • linkreport

andrew: See the end; he did an MSA analysis as well and it links to the spreadsheet. The results come out mostly the same, except LA moves up from 5 to 3.

by David Alpert on Apr 15, 2013 11:50 am • linkreport

@ Ben Ross:I suspect that Boston would rank much higher if you looked at lane-miles instead of miles of highway. They have much fewer of the six- and eight-lane arterial roads that predominate in our suburbs.

But they have plenty of highways and spurs. They have I-93 straight through (under) downtown, I-95 as a first beltway and I-495 as a second beltway. On top of that you have I-90, it's spurs and all the other X95s (not that all of RI is included in the Boston area here).

by Jasper on Apr 15, 2013 11:51 am • linkreport

Jasper = but I bet suburban arterials make up a higher pct of the lane miles in most metros than interstate highways do (even if the latter are more expensive per lane mile)

by AWalkerInTheCity on Apr 15, 2013 12:00 pm • linkreport

This measure of efficiency strikes me as misguided, much the way "vehicles per hour" does not capture levels of service provided by bus and carpool. "People per road mile" doesn't capture lanes per road mile, or for that matter, provide quantitative or qualitative information about how the roads are used. Next metric please.

by JLK on Apr 15, 2013 12:12 pm • linkreport

Where did the road miles data come from? Is it measuring lane miles or what?

by MLD on Apr 15, 2013 12:49 pm • linkreport

A better measure of efficiency is capital efficiency. That is, money spent on roads per person instead of road-miles per person. The reason is that a project like the Big Dig or the Wilson Bridge costs billions of dollars while it creates relatively few road-miles. By comparison, building road-miles in the Texas desert isn't nearly as costly.

A better measure would be the 10 year average of local+federal transportation spending per the 10 year average population.

by Falls Church on Apr 15, 2013 12:53 pm • linkreport

Movement along those roads creates pollution and costs the users time. All else equal, it is more efficient to build, use, and maintain fewer roads per person.

Having fewer roads doesn't necessarily mean that movement along those roads will cost users less time. It's certainly possible that having fewer roads means more traffic congestion, costing users more time.

by Falls Church on Apr 15, 2013 12:58 pm • linkreport

What if there are less primary roads but more secondary roads?

by Richard Bourne on Apr 15, 2013 1:10 pm • linkreport

"Roads" includes everything in the National Highway Planning Network's dataset:

Lane miles would definitely be better than road miles, but the number of lanes was not available for every road in the dataset.

As commenters have noted, regions with wide roads, or with many local roads, have an advantage on this metric.

by Chris DP on Apr 15, 2013 1:22 pm • linkreport

New York can probably be forgiven its unique geography. The Washington region has really no excuse for our sprawl.

by Alan B. on Apr 15, 2013 1:26 pm • linkreport

So many caveats to this... as others noted: roadway classifications. Also connectivity and configuration: there could be an grid, but a grid that's broken up by cul-de-sacs isn't a grid; or an efficient & connected grid might be arguably more efficient than Boston's dizzying maze.

by Bossi on Apr 15, 2013 3:05 pm • linkreport

Alan B. I'd think cities with constraint like NY should actually have the higher population densities, and areas with little constraint, like DC, tend to have lower density. Not saying it's good that land plentiful areas have sprawl, but much of the reason for sprawl deals with local level land use decisions, and I've noticed local land use deciders tend to favor sprawl, until land looks like it will run out, regardless of the social/environmental costs. We're actually the best ranked on the list of people per road mile out of the non constrained metro areas.

For as much fun as we could poke at Miami as seeming like every other sun belt car centric city, it is a fairly dense urban area. They have a lot of 'dense suburbs' similar to our inside the Beltway communities. Because of the Everglades, they don't have hundreds of square miles of 1-3 acre lots perched on top of rolling hills on cul-de-sacs.

by Gull on Apr 15, 2013 4:32 pm • linkreport

@Gull They don't have rolling hills because South Florida is flat. :)

by Wilsonia on Apr 15, 2013 7:18 pm • linkreport

Just for comparison, the entire country or Switzerland has a density of about 1,600 inhabitants per mile of street. And I don't think there is a six lane road in the country.

by Egk on Apr 15, 2013 7:35 pm • linkreport

If you're counting arterial roads according to the National Highway System, then it seems to me that you're basically only counting the marked lines on maps like and And just comparing those two maps makes me think that Miami's high ranking is more an artifact that so few of its roads are considered "national highways" compared to, say, Fairfax County.

by Joshua Cranmer on Apr 15, 2013 9:39 pm • linkreport

Gull that's certainly true of the city, but I was thinking about the MSA/CSA as a whole. Part of the reason that north jersey is a mess of highways is all the bridges, wetlands and water bodies in the area that make for convoluted highways.

by Alan B. on Apr 16, 2013 9:15 am • linkreport

Regognizing that it's preposterous to consider vast tracts of the Mojave desert as "in" the LA metro area, LA has the same dynamic as Miami going for it...ocean on one side, mountains on the other.

by Brian on Apr 16, 2013 9:31 am • linkreport

Vamos Miami!

by Kyle on Apr 16, 2013 10:46 am • linkreport

honestly , none of these people have visited miami if they think it deserves anything in the top of any catagory revolving smart street design

by carlos on Apr 16, 2013 1:41 pm • linkreport

Carlos, what a curmudgeon! Miami is awesome.

by Kyle on Apr 18, 2013 2:21 pm • linkreport

This article is a rediculous over simplification. What this table really explains is why the Miami area is choking in traffic; There is simply not enough road capacity. Expansion of transportation infrastructure (including roads) has not kept up with development and population growth. Miami doesn't seem too efficient to the average peak hour commuter who loses more than a work per year to traffic delays. Check out the Urban Mobility Report. A better way of doing this comparision would be to look at vehicle registrations per mile as opposed to population per mile.

by Wayne on Jun 4, 2014 7:36 pm • linkreport

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