Greater Greater Washington

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National links: Our cities are growing

The population in nearly all of the US' big cities is increasing, Seattle's mayor wants to reward streets that aren't just for cars, and a new kind of wood could change building design. Check out what's happening around the country in transportation, land use, and other related areas!


Photo by theirmind on Flickr.

Growing cities: New US Census numbers show cities continuing to grow, with 19 of the top 20 cities gaining population over the last year. Only Chicago showed a decrease. Smaller cities like Austin saw rapid growth, while Detroit continues to decline. (USA Today)

Seattle and the "war on cars": Seattle's mayor wants to rank streets based on how many single-occupant vehicles use them, and make development decisions based on the rankings. A Seattle Times opinion writer says there's no denying that the city is engaged in a war on cars, but a former mayor says designing places just for cars leads to an inability to walk places, struggling retail and housing, and more crime and blight. (Seattle Times, Crosscut)

Invisible wood: Scientists have created a clear wood that's stronger than normal. It could one day be used in place of plastic building materials or glass for windows, as it should help lower both heating costs and fuel consumption. (CNN)

Transit progress in LA: A new stretch of track, called the Expo Line, started running between Santa Monica and downtown Los Angeles last week. This isn't just a new line for LA's rail network (though the 7 new light rail stations are nice). It's an approach to reconnecting the region that's built on the original transit system. (Los Angeles Times)

Revamping transit advocacy: The American Public Transportation Association, which advocates for transit all over the US, has come under fire lately; it even lost by far its largest member, New York's MTA. One way the organization can move forward: focus less on supporting transit at all costs, and more on transit that riders want to use. (TransitCenter)

In simple terms: Urban sewer systems and watersheds are complex, so the Center for Urban Pedagogy (n. the method and practice of teaching) created a diorama to explain them. The teaching tool won a national design award from the Smithsonian's Cooper Hewitt Museum, and is just the latest project from an organization that helps people, especially those who may not be able to read or speak English, understand the world around them. (Smithsonian Magazine)

Quote of the Week

"When I was 13, I built a very intricate Lego city that suffered a huge tragedy when it was accidentally hit with a vacuum cleaner. As I rebuilt the buildings I created memorials with plaques that I printed out on my dot matrix printer commemorating The Great Vacuum Incident of 1988. Legos didn't make me love architecture, but they gave my love of architecture a place to develop." - Renowned architect Mark Kushner discussing how adult architects play with Legos. (Fast Company Design)

Demographics


Who are DC's 1,000 "new residents per month?"

You may have heard that DC's population is increasing by approximately 1,000 per month. That's a true popular statistic. But it's not really true to say that 1,000 people are moving into DC each month. What is really driving this number?


Not officially one of the new residents. Photo by Smithsonian's National Zoo on Flickr.

In short: people being born and dying, and large numbers of people moving in and out of DC. On balance, if you add up all of these numbers, you get about 1,000 a month.

Births: Some of DC's new residents are babies. 9,593 humans were born in DC from July 1, 2014 through June 30, 2015, according to the US Census' 2015 "Vintage Population Estimates," or about 800 a month.

Deaths: Meanwhile, some people die. In that same time span, it was 5,218, or about 435 a month. Together, that makes the net "natural population change" 365 people a month.

Domestic migration: Other people move into or out of DC. The Census also estimates that DC had a net domestic migration of 311 people a month. In other words, the number of people who moved to DC from other parts of the US was 311 people more than the number who moved the other way.

International migration: Finally, people move to and from DC from other countries as well. There was a net of 379 such people a month from 2014-2015. As you can see from the graph below, that number has stayed more consistent than the net domestic migration:


Data from US Census Vintage 2015 Population Estimates. Numbers do not include pandas.
* Residual is where the estimates for individual components don't quite add up to the total population change.

This graph shows, with some variation, that roughly a third of the population change is natural, a third domestic migration, and a third international. However, it'd be very inaccurate to say the three are about equal.

That's because the net domestic migration number, in particular, conceals a huge amount of "churn." Remember how, above, we said that 800 babies are born a month and 435 people die. Since those are almost entirely not the same people, there aren't 365 people coming into the world a month; instead, 1,235 people total either enter or leave this life.

The corresponding number of people who moved between DC and another part of the US per was between 7,000 and 8,000 a month in either direction, based on data from the Internal Revenue Service and the Census's American Community Survey.


Purple bars from US Census Vintage 2015 Population Estimates. Red and green bars are very rough estimates extrapolated from IRS and American Community Survey data.

This graph shows the rough magnitude of the churn in each category. The domestic migration comes out to a net of about 400 a month over the last five years, but that's two large numbers balancing out to one small one. The size of those components is partly why the domestic number fluctuates more from year to year.

It also makes it hard to drill down. We'd love to know how many of the 8,000 movers per month are going to or from the immediate metro area versus elsewhere in the US. Unfortunately, according to Jeannette Chapman of George Mason University's Center for Regional Analysis (who provided the data for this post), the available public data sources have limitations.

The Census' American Community Survey uses a small sample that's only good enough to conclude that net domestic migration was somewhere between -13,000 and +7,500 in 2014.1 The IRS has data on people who filed taxes in one jurisdiction and then changed to another, but not everyone can be matched over two years and not everyone files taxes.2 Both of these data sources can tell us a lot about movers, but doesn't completely nail down "the" absolute number.

But the overall net population change numbers are more solid, and in the end, some more people are born than die, and more people come into DC from around the nation and the world than leave.

The people moving domestically and internationally, in general, need housing units; the people born don't right away, but most of their families eventually need larger housing spaces. DC has added approximately 10,000 new jobs per year over the last five years, and many of those job holders will live in the city.

How much housing DC is adding, and how much it needs to build to meet the need, will be the subject of a future post.

1 If you estimate the domestic migration using the ACS and IRS data, as Chapman did, they actually show a net negative domestic migration—more people moving out of DC than in. But, Chapman said, that likely doesn't mean more people actually moved out of DC; the Census' Population Estimates show an increase, and they incorporate more data sets and sophisticated modeling to come to these numbers.

2 The data set only covers people who file taxes and do so by the April 15 deadline. That excludes
many lower-income people, higher-income people, and misses some, like young people, who may still be using another address like their parents'. New filers (like recently-married or first-time jobholders) also don't have two years of history to compare. In 2013, about 15% of people who filed federal taxes (either as the filer or a dependent) couldn't be matched to 2012.

Development


DC added record housing in 2015. That's slowing down price increases.

In 2015, DC permitted more new housing units—4,956, to be exact—than in any year since the Census started keeping track in 1980. This pace of housing growth compares favorably to other cities, and there's reason to believe it's helping to slow rent increases.


Photo by Ryan McKnight on Flickr.

The record-setting year is most likely due to both long-term factors (a shift towards city-living among young professionals) and short-term, cyclical ones (federal government job growth having recovered from the sequester).

The composition of 2015's housing permits in DC skewed heavily towards large multifamily buildings, as it has in recent years. Neighborhoods like Navy Yard and Southwest Waterfront, where there are fewer neighbors to oppose large development projects, are contributing strongly to the city's overall housing production.


Graph by the author, with data from the Census Bureau.

Accounting for population, DC got more permits than most other major coastal cities

How does DC's year stack up against other cities? Well, it's somewhat difficult to compare these numbers across cities for a few reasons:

  • Initial population matters. For example, 10,000 new units in one year would be a ton for DC, but very few for a bigger city like New York.
  • Population growth matters too. Baltimore has about the same number of people as DC, but there's little reason to build new houses if few people are moving to town.
  • Cities have arbitrary political boundaries. We could use a standardized geographic unit (like MSAs), but that captures a lot of single-family, sprawling development. At the end of the day, we're interested in the extent to which cities are allowing their cores to densify.
But we can still make some back-of-the-envelope calculations. One useful starting place is to scale permits by a city's population. In 2015, DC permitted 7.5 housing units per 1,000 residents.

That matches or exceeds the rates of most comparable coastal cities: Boston (also 7.5), Portland (7.1), New York (6.6, an outlier driven by regulatory uncertainly for the usually low-growth city), San Diego (4.5), San Francisco (4.3), and Los Angeles (4.1). It easily surpassed cities with lower-than-average job growth, like Philadelphia (2.4) and Chicago (2.1). And DC was out-produced by growth-happy Seattle (17.0), Denver (12.0), and Austin (11.0).

There's evidence that all this new supply is slowing rent growth

In recent years, real estate analysts have noted that DC's higher pace of building has led to rents that are slowing in growth, or even declining. This effect is especially seen at the higher end of the market, since most new construction is luxury.

Here's Multifamily Executive covering a new Yardi Matrix report:

The cities that had the smallest rent gains in 2015 were Richmond, Va.; Washington, D.C.; and Baltimore. Echoing other reports, Yardi says Washington's rent gains have been held back because of the large amount of new supply in its market, while Baltimore still lacks job growth. These cities can expect to see similar results in 2016, Yardi says.
A Bloomberg reporter who interviewed DC developers last summer collected relevant anecdotes:
Tepid job gains and a spate of construction that created almost 20,000 units in the past two years made Washington one of the worst markets for US landlords, forcing owners to grant tenants concessions such as months of free rent to keep new luxury apartments from going empty.
And early last year, The Washington Post wrote that an increasing supply had driven down rents, partly by pushing landlords of luxury buildings to lower prices so they could compete.

Any effort to make our region more affordable will require a good deal more market rate housing than what we currently have. Hopefully, DC will build on the successes of 2015 and continue to allow high levels of dense housing construction.

Government


Here's a map of where people in our region commute to, and how

Commuters in our region mostly travel to work by car, which is the same as the rest of the country. But second to driving, people here use public transportation at higher rates than the national average.


Photo by Kevin Utting on Flickr.

This is according to Who Drives to Work? Commuting by Automobile in the United States: 2013, a report the US Census Bureau published in August based on 2013's American Community Survey.

The survey gathers demographic and travel to work data from 1 of every 38 households nationwide each year and asks participants how they travel to work. The question asked to determine travel mode to work is "How did this person get to work last week?"

The interactive map below is based on survey results from counties the Census defines as being in the "DC metro region."


Map by the author.

Here are some things we've noticed about our region. Feel free to tell us what you see in the comments below!

  • For commutes within Arlington County, Alexandria, and DC, "other" is a large chunk of the travel mode. That's probably an indicator that lots of people in those areas walk or bike to work.

  • People traveling between Arlington and DC actually use a mode other than driving alone more than half the time.

  • Commuters from counties located on I-95 South (Spotsylvania County, Fredericksburg City, Stafford County, Prince William County) carpool at rates higher than any others most likely due to the I-95 HOT Lanes.

  • In Rappahannock County more than 41% of commuters chose "other." That distinction includes working from home, and it makes sense that the number in Rappahannock is high since a lot of people there are self-employed and work in the agricultural sector. Other fringe counties like Warren, Clarke, and Jefferson have relatively high "other" mode shares as well.
It's important to keep in mind that the ACS is a sample survey so there is inevitably sampling error. You can see margins of error for each transit mode by hovering over the data. In general data from more populous counties will be more reliable.

Lots of people drive in our region, but not as much as other places

Among the biggest takeaways from the report is that DC has some of the highest commuting rates in the country. In other words, a whole lot of people travel to a county outside of the one they live in to get to work.

But our region ranks eighth-lowest among places where people drive to work, with 75.7% of commuters doing so compared to the national average of 85.8%. Of the remaining DC commuters, 8% choose Metro. The national average for all public transit use is 5.2%.

The list of lowest auto use is led by New York City with 56.9%, followed by Ithaca, NY with 68.7% and the Bay Area rounds out third at 69.8%. New York City is certainly unsurprising, Ithaca has a big college population that mostly walks, and in the Bay, the well developed bus and trolley bus network is a popular mode for commuters.

According to the report, the rate of driving to work alone or with others, on the rise since 1960, peaked in the year 2000 at 87.9% before dropping to the current rate. The list of cities with the biggest drops in auto use since 2006 were in the San Francisco Bay Area, Boston, and Durham-Chapel Hill. Our region did not make it on the top 15 in that category.

Transit


Get your March Madness on with two games that test your city smarts

In the mood for yet another bracket? Or maybe after filling one out, you're looking for a guessing game where you've at least got some idea of what you're doing? These two games are fun ways to test what you know about cities.

Census bracketology

The first is the Census Bureau's Population Bracketology. You can play using either state or metropolitan area populations, choosing which of the paired "contestants" has the greater population.

Many of the choices are intuitive, but it's often surprising to see how large many younger, Sunbelt cities have grown. The difference would have been much more obvious if the Census pitted city populations head-to-head—municipalities in the east are usually much smaller than those in the west.

Jonathan Neeley, our staff editor, said "when cities I don't have a great gauge of came up, it got me thinking about density versus sprawl. I obviously know New York beats Jacksonville. But does Baltimore beat Riverside? Does Portland beat Orlando?"

You may know populations, but how about transit lines?

If you've got a sharper memory for geography than for facts and figures, you might prefer Chicago-based CNT's "Guess the City," featuring transit stops color-coded by service frequency (drawn from GTFS data):

CNT guess the city

Not all of the choices are so obvious, though, especially in suburbs with sparse transit networks:

CNT guess the city

One hint: keep in mind that many eastern cities have radial street networks, whereas western cities almost always have gridded streets. Also, bigger cities almost always have denser transit networks. CNT's site also lets users generate a color-coded "Transit Access Score" that measures how accessible any given location is via transit.

Transit


Governor Hogan thinks only 10% of Marylanders use transit. Actually, 25% or more do.

Maryland Governor Larry Hogan says that Maryland should shift its focus away from transit toward building more roads because (he says) less than 10% of people use transit. But the real number is far more.


Bethesda. Photo by ehpien on Flickr.

Hogan's mistaken assertion comes from the Census Bureau's American Community Survey (ACS), which estimates that 9.1% of Maryland's 2.9 million workers over the age of 16 used transit as their primary mode for commuting in 2013.

But that's not a measure of the number of people who use transit. Lots of people who live and work in Maryland cannot take transit to work, but use Metro whenever they venture into DC. And most people who drive to work in the District use Metro at least sometimes.

Even some daily users of transit do not show up as transit users in the ACS, because if you drive 20 miles and ride Metro the last 12 miles, the survey counts you as a driver.

National Census data can help estimate Maryland's transit use

No survey has estimated the number of Marylanders who use transit. But Census surveys show that nationwide, total transit users are about two to three times the number of transit commuters. There is no proof these patterns hold in Maryland, but let's assume that they do.

The American Housing Survey (Table 1) showed that about 6.6% of US households have at least one person who uses transit most of the time to get to work, that people in 17.4% of all households use transit in some way, or more than 2½ times the number of households. If we apply this ratio to Maryland, then 24% (2.64 times 9.1%) of Marylanders would use transit.

Table 1: Comparing the share of people who use transit with the share of people for whom transit is the primary mode for traveling to work
Percent of Households1Percent of Employees2
USANortheastUSANortheastMaryland
Transit Users17.432.5---
Use Transit for Traveling to Work
Most of the time6.615.35.014.39.1
Sometimes3.66.0---
Never7.111.1---
1 US Census Bureau, 2013 American Housing Survey
2 US Census Bureau, 2013 American Community Survey

That's not the only way to interpret the data. As Table 1 shows, the transit mode share for Maryland, 9%, is 1.8 times the national average of 5%. If the proportion of Maryland households using transit is also 1.8 times the national average of 17.4%, then 31.3% of Maryland households use transit.

Which of these two above estimates, 24% or 32%, is more defensible? It's hard to say. But there are two reasons to think that applying these nationwide relationships understates transit use in Maryland.

First, using household data inherently shows a smaller ratio of all transit users to daily transit users than a comparable survey of individuals would. (If you want to explore this point in detail, here are a few numerical examples).

Second, occasional users tend to outnumber daily users on rail lines but not on bus lines, according to Census data. So in states like Maryland with a lot of rail, occasional transit users will tend to outnumber regular users significantly compared to the national average. Assuming the national average ratio of occasional to regular transit users might then underestimate the number of occasional users and the total.

A Washington Post poll also shows high transit use

A few years ago, the Washington Post pollled area residents on how they get to work. The poll found that 20% of area residents used transit to get to work, which is similar to the county-level data from the American Community Survey. 88% of respondents said they use Metrorail at least sometimes.

To be conservative, let's assume that all of the non-transit users are outside DC and Arlington. That means 85% of residents use Metrorail in the rest of the region. Let's also assume that transit use is no higher in Prince George's and Montgomery than the rest of the region—a conservative estimate because Census data show these two Maryland counties have a higher transit mode share than Fairfax or Loudoun.

Because Prince George's and Montgomery counties alone account for 32% of the Maryland population, if 85% of those residents use transit, then that's 27% of the state's population right there.

Table 2: Number of Marylanders who use transit as the primary mode for traveling to work
CountyTotalPercent of all workers
Montgomery83,70615.6
Prince George's78,68517.4
Baltimore city50,51918.8
Baltimore County19,6104.8
Anne Arundel13,1574.6
Howard5,2713.3
Charles4,0415.2
Frederick3,2112.6
Harford2,4371.9
Rest of Maryland7,9231.6
Total268,5609.1
Source: US Census Bureau, 2013 American Community Survey

As Table 2 shows, Montgomery and Prince George's account for about 60% of the transit mode share. If they also represent 60% of the transit users in Maryland, then we could conclude from the Post poll that fully 45% of Maryland residents use transit at least sometimes.

Admittedly, some of those people use it infrequently, but even occasional users get value from transit, particularly since they use it most when traffic is heaviest.

As a newly elected governor, Mr. Hogan is reasonably trying to both discern his mandate and articulate it. He may be correct that statewide, more people in Maryland are worried about roads than improving transit. But the number of people who use transit is far greater than he acknowledges, and in the Washington area, probably a majority.

Demographics


88% of new DC households are car-free

For the vast majority of DC's new residents, Car Free Day (September 22) isn't a once-a-year event, but a year-round occasion. Between 2010 and 2012, the number of car-free households in in the District of Columbia grew by 12,612—fully 88% of new households citywide.


Graph by the author with data from the US Census.

During that time, the number of car-free households in DC has grown by 14.3%, increasing their share of all households from 35% to 37.9%. By contrast, the District only added 1,662 car-owning households since 2010, an increase of just 1.0%.

The percentage of households with one, two, and three or more cars all declined. This is even though typical DC households have considerably more money with which they could buy cars: median incomes grew by 9.3% over the same time period.

More specifically, the Census Bureau's American Community Survey (using one-year estimates, and accessible via factfinder2.census.gov) showed that the number of car-free households in DC increased from 88,390 to 101,002, and the total of all households went from 252,388 to 266,662.

The ACS has also picked up on other consequences of DC's growing car-freedom, like a sharp decline since 2007 in the number of DC residents who drive to work.

This doesn't mean that new apartment buildings' garages are all seven-eighths empty, of course. There is considerable churn among households, especially in urban areas: fully 36.5% of DC households moved at some point between 2010 and 2012, with most of those moves taking place within DC. Some who already lived in DC and own cars moved into new buildings, and others moved from the city and took cars with them.

Some existing households bought cars, and others sold theirs. New households are created when couples or roommates split, when kids strike out on their own, or when someone new moves to town. (One set of new arrivals not contributing to the trend: students living in dorms are not considered households, as the Census defines the term.)

But the net effect of all these changes is the same: The people moving into DC, or striking out on their own here, are almost entirely car-free. They are very different from current residents in that regard: only 12% of new households own cars, compared to 62.1% of current DC households. These new households are demanding many fewer parking places, much less rush hour road space, and much less gasoline.

Parking minimums prepare for car ownership that just doesn't exist

These statistics show why DC does not need to continue requiring costly and environmentally destructive new parking garages within new developments that accommodate the city's growing population.

However, some longtime neighborhood activists have been fighting lower parking minimums. At this week's hearings on zoning code changes, multiple opponents of lower parking minimums also cited Census data to argue that parking was necessary: they said that the numbers of cars per household in DC was "holding steady" at 0.9.

In fact, the number of cars per household in DC declined from 0.90 to 0.86. Maybe if you round off to one decimal place, both numbers become 0.9—proof that nothing has changed!

These trends aren't unique to DC; instead, they're consistent with what other growing, dense cities are seeing. Michael Rhodes from Nelson\Nygaard, a transportation consulting firm, recently calculated that in San Francisco, a similar 88 percent of new households are car-free. DC's car-freedom is also consistent with national and global trends pointing towards lower urban car ownership recently and into the future. The decline in car ownership should come as little surprise given DC's booming population of auto-averse millennials.

Government


DC's daytime population is over a million

According to a US Census report, the District of Columbia's daytime population, including commuters, swells to over 1,000,000. The difference between DC's day and night populations is second greatest in the US.


Downtown DC.

The report dates from 2010 so the numbers are surely a bit different today. With DC's (then) nighttime residential population of 584,400, its 1,046,036 daytime population represents a 79% increase. Among US counties, only New York County (Manhattan) has a larger percentage increase.

Arlington looks much the same. Its 26% increase in daytime population is 13th largest nationally. That's higher than San Francisco on the list.

At the other end of the spectrum, two DC suburbs top the list of places with decreased daytime population. Dale City and Centreville in Northern Virginia both drop by over 40%, making them America's ultimate bedroom communities.

Montgomery County's Germantown is Maryland's top entrant on that list; it clocks in at #20, with a decrease of 31%.

Part of the explanation for this is simply where boundaries are drawn. For example, even though Houston has a large downtown with many commuters, it doesn't appear on the increased daytime population list because the City of Houston annexed so many of its suburbs that more of its commuters still technically live within the city limits. Likewise, Houston's Harris County is gigantic and more or less envelopes the entire metropolis, so there's little difference at the county level either.

Geographically smaller jurisdictions in large metropolitan areas are disproportionately more likely to show up in this data. So it's not a great comparison of commuting patterns across different metropolitan regions. But it's nonetheless interesting to know.

Cross-posted at BeyondDC.

Bicycling


DC bike commuting more than doubled since 2000

It's pretty clear from looking around DC that many people are bicycling. The Census has published new numbers that show how many are.


Image from the US Census.

3.1% of commuters in the District bike to work, according to the American Community Survey. That puts DC seventh among cities over 200,000 people. In 2000, that number was only 1.2%, for an enormous jump.

Plus, the survey doesn't even capture all of the bicycling. It just asks about commute to work trips. Many people bike for other trips even if they drive, take transit, or walk to work. And if you bike a short distance to a longer Metro ride, the Census would capture your commute as being by Metro, not by bike.

DC also has the second-highest rate of people walking to work, 12.1%, behind Boston's 15.1%.

The District is very different than the whole region (which includes the inner suburban counties and the far exurban ones). For the larger metro region, 3.2% of people walk to work, says the Census report; it doesn't say how many people bike to work region-wide.

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