Sweet Summer Air of Subway Cars

For those of my readers who live in a city where the subway or underground is a great means of getting around the city, you know you really miss that late Saturday night/early Sunday morning bouquet in the air. Though as this New York Times piece explains, sure it smells bad, but that air is probably safer than you dining indoors at a restaurant or even a child attending class in person.

The piece focuses on New York City subway cars, but they are very similar to the rest of the stock used in the United States. It uses a scrolling reveal to show how the air circulation and filtration systems work. Then it concludes with a model of how a person sneezing appears, both with and without a mask. (Spoiler, wear a mask.)

It’s a really nicely done and informative piece. It compares the rate of air recycled in a subway car to that of several other locations, and the results were a bit surprising to me. Of course, early on in the pandemic before we began to fully understand it, the threat was thought to be from contaminated surfaces—and let’s be honest, there are a lot of contaminated surfaces in a New York City subway car—but we now know the real risk is particles breathed/coughed/sneezed out from one’s mouth and nose. And we can now see just how efficient subways are at cycling and filtering that air.

Credit for the piece goes to Mika Gröndahl, Christina Goldbaum, and Jeremy White.

Americans Can’t Kick the Auto Habit

After looking this week at the growth of the physical size of cities due to improvements in transport technologies, the increasing density of cities, and then the contribution of automobile (especially personal cars) to carbon dioxide emissions, today we look at a piece from the Transport Politic comparing US and French mass transit ridership to see whether the recent decline in US ridership is inevitable or a choice made by consumers and policymakers. Spoiler: it’s not inevitable.

The article makes use of a few graphics and an interactive component. The lead-in graphic is a nice line chart that runs with the spaghetti nature of the graphic: lots of line but only two are really highlighted.

The French are definitely better than the US here.
The French are definitely better than the US here.

Light grey lines and light blue lines encode the US and French cities under study. But only the lines representing the averages of both the US and France are darkly coloured and in a thicker stroke to stand out from the rest. Normally I would not prefer the minimum of the y-axis being 50%, but here the baseline is actually 100% so the chart really works well. And interestingly it shows that prior to the Great Recession, the United States was doing better than France in adoption of mass transit, relative to 2010 numbers.

But then when you directly compare 2010 to 2018 for various US and French cities, you get an even better chart. Also you see that French cities reclaim the lead in transit growth.

A lot of declines on this side of the pond.
A lot of declines on this side of the pond.

These two static graphics, which can each be clicked to view larger, do a really great job of cutting through what some might call noise of the intervening years. I do like, much like yesterday’s post, the comparison of total or aggregate ridership to per capita numbers. It shows how even though New York’s total ridership has increased, the population has increased faster than the ridership numbers and so per capita ridership has declined. And of course as yesterday’s post examined, in the States the key to fighting climate change is reducing the number of people driving.

What I cannot quite figure out from the graphic is what the colouration of the lines mean. I thought that perhaps the black vs. grey lines meant the largest cities, but then LA would be black. Maybe for the steepest declines, but no, because both LA and Boston are grey. I also thought the grey lines might be used when black lines overlap to aid clarity, but then why is Boston in grey? Regardless, I like the choice of the overall form.

But where things go really downhill are the interactive charts.

Just what?
Just what?

Talk about unintelligible spaghetti charts. So the good. The designer kept the baseline at 100% and set the min and max around that. After that it’s a mess. Even if the colours all default to the rainbow, the ability to select and isolate a particular city would be incredibly valuable to the user. Unfortunately selecting a city does no such thing. All the other cities remain coloured, and sometimes layered atop the selected city.

I would have thrown the unselected cities into the greyscale and let the selected city rise to the top layer and remain in its colour. Let it be the focus of the user’s attention.

Or the designer could have kept to the idea in the first graphic and coloured American cities grey and French cities light blue and then let the user select one from among the set and compare that to the overall greyed/blued masses and the US and French averages.

Overall, it wasn’t a bad piece. But that final interactive bit was questionable. Unfortunately the piece started strong and ended weak, when the reverse would have been preferable.

Credit for the piece goes to Yonah Freemark.

Auto Emissions Stuck in High Gear

The last two days we looked at densification in cities and how the physical size of cities grew in response to the development of transport technologies, most notably the automobile. Today we look at a New York Times article showing the growth of automobile emissions and the problem they pose for combating the greenhouse gas side of climate change.

The article is well worth a read. It shows just how problematic the auto-centric American culture is to the goal of combating climate change. The key paragraph for me occurs towards the end of the article:

Meaningfully lowering emissions from driving requires both technological and behavioral change, said Deb Niemeier, a professor of civil and environmental engineering at the University of Maryland. Fundamentally, you need to make vehicles pollute less, make people drive less, or both, she said.

Of course the key to that is probably in the range of both.

The star of the piece is the map showing the carbon dioxide emissions on the roads from passenger and freight traffic. Spoiler: not good.

From this I blame the Schuylkill, Rte 202, the Blue Route, I-95, and just all the highways
From this I blame the Schuylkill, Rte 202, the Blue Route, I-95, and just all the highways

Each MSA is outlined in black and is selectable. The designers chose well by setting the state borders in a light grey to differentiate them from when the MSA crosses state lines, as the Philadelphia one does, encompassing parts of Pennsylvania, New Jersey, Delaware, and Maryland. A slight opacity appears when the user mouses over the MSA. Additionally a little box remains up once the MSA is selected to show the region’s key datapoints: the aggregate increase and the per capita increase. Again, for Philly, not good. But it could be worse. Phoenix, which surpassed Philadelphia proper in population, has seen its total emissions grow 291%, its per capita growth at 86%. My only gripe is that I wish I could see the entire US map in one view.

The piece also includes some nice charts showing how automobile emissions compare to other sources. Yet another spoiler: not good.

I've got it: wind-powered cars with solar panels on the bonnet.
I’ve got it: wind-powered cars with solar panels on the bonnet.

Since 1990, automobile emissions have surpassed both industry emissions and more recently electrical generation emissions (think shuttered coal plants). Here what I would have really enjoyed is for the share of auto emissions to be treated like that share of total emissions. That is, the line chart does a great job showing how auto emissions have surpassed all other sources. But the stacked chart does not do as great a job. The user can sort of see how passenger vehicles have plateaued, but have yet to decline whereas lorries have increased in recent years. (I would suspect due to increased deliveries of online-ordered goods, but that is pure speculation.) But a line chart would show that a little bit more clearly.

Finally, we have a larger line chart that plots each city’s emissions. As with the map, the key thing here is the aggregate vs. per capita numbers. When one continues to scroll through, the lines all change.

Lots of people means lots of emissions.
Lots of people means lots of emissions.

There's driving in the Philadelphia area, but it's not as bad as it could be.
There’s driving in the Philadelphia area, but it’s not as bad as it could be.

Very quickly one can see how large cities like New York have large aggregate emissions because millions of people live there. But then at a per capita level, the less dense, more sprawl-y cities tend to shoot up the list as they are generally more car dependent.

Credit for the piece goes to Nadja Popovich and Denise Lu.

Mapping the Growth of Cities

This is an older piece from back in August, but I was waiting for a time when I would have some related articles to post alongside it. To start off the series of posts, we start with this piece from CityLab. As my titles implies, it looks at the growth of cities, but not in terms of people or technology but in terms of area/land.

The basic premise is that people look for a 30-minute commute and have done so throughout history. To make that point, the authors look at how transport technology evolved to enable people to live and work at further distances from each other, expanding the urban core.

The designer then chose to overlay the city limits of several cities largely defined by these technologies atop each other.

From small, compact, and dense to large, sprawling, and fluffy.
From small, compact, and dense to large, sprawling, and fluffy.

Conceptually the graphic works really well. The screenshot is of an animated. gif leading into the article that step-by-step reveals each city. However, throughout the article, each de facto section is introduced by a city outline graphic.

The graphic does a really nice job of showing how as technology allowed us to move faster, people chose to be further removed from the city core. Of course there are often multiple factors in why people may move out of the core, but transport certainly facilitates it.

Credit for the piece goes to David Montgomery.

Oh the Places I’ve Been

This afternoon I am off on a flight to Austin, Texas for a friend’s wedding in nearby Kyle, Texas. Two years in a row I’ve been to Texas in October. And so that felt like a good enough reason to update my counties visited map that, according to my files, I haven’t updated since 2015.

In those four years, before I moved from Chicago to Philadelphia, I explored Wisconsin for genealogy purposes. Then after said move, I have visited Las Vegas for bachelor party—now the furthest west in the United States I have ever visited. And work trips have sent me to St. Louis and Dallas, the former of which allowed me a nice train ride from St. Louis to Chicago across central Illinois. I have also done some genealogy research up in western New York bookending a bachelor party to the Finger Lakes.

I'm clearly an East Coast guy with a decent representation of the Midwest.
I’m clearly an East Coast guy with a decent representation of the Midwest.

At a state level that makes 23 states visited plus two through which I’ve travelled (Connecticut and Rhode Island). Plus I’ve visited DC. Almost halfway there to visiting half the United States.

With the wedding Saturday, I am on holiday Friday. Plus, Monday is a bank holiday and so I will be posting again from Tuesday.

Baby You Can Drive My Non-automobile Personal Mode of Transportation

Last week was the climate summit in New York, and the science continues to get worse. Any real substantive progress in fighting climate change will require sacrifices and changes to the way our societies function and are organised, including spatially. Because one area that needs to be addressed is the use of personal automobiles that consume oil and emit, among other things, carbon dioxide. But living without cars is not easy in a society largely designed where they are a necessity.

But over at CityLab, Richard Florida and Charlotta Mellander created an index trying to capture the ability to live without a car. The overall piece is worth a read, but as usual I want to focus on the graphic.

The Northeast is where it's at with its dense cities designed for a pre-automobile era
The Northeast is where it’s at with its dense cities designed for a pre-automobile era

It’s nothing crazy, but it really does shine as a good example of when to use a map. First, I enjoy seeing metro maps of the United States used as choropleths, which is why I’ve made them as part of job at the Philly Fed. CityLab’s map does a good job showing there is a geographic pattern to the location of cities best situated for those trying to live a car-free life. Perhaps not surprisingly, one of the big clusters is the Northeast Corridor, including Philadelphia, which ranks as the 17th best (out of 398) and the 7th best of large metro areas (defined as more than one million people), beating out Chicago, ranked 23rd and 8th, respectively.

Design wise I have two small issues. First, I might quibble with the colour scheme. I’m not sure there is enough differentiation between the pink and light orange. A very light orange could have perhaps been a better choice. Though I am sympathetic to the need to keep that lowest bin separate from the grey.

Secondly, with the legend, because the index is a construct, I might have included some secondary labelling to help the reader understand what the numbers mean. Perhaps an arrow and some text saying something like “Easier car-free living”. Once you have read the text, it makes sense. However, viewing the graphic in isolation might not be as clear as it could be with that labelling.

Credit for the piece goes to David Montgomery.

Baby, It’s Hot Outside

Those of you living on the East Coast, specifically the Mid-Atlantic, know that presently the weather is quite warm outside. As in levels of dangerous heat and humidity. Personally, your author has not left his flat in a few days now because it is so bad.

Alas, not everyone has access to air conditioning in his or her abode. Consequently, they need to look to public spaces with air conditioning. Usually that means libraries or public buildings. But here in Philadelphia, have people considered the subway?

Billy Penn investigated the temperatures in Philadelphia’s subsurface stations along the Broad Street and Market–Frankford Lines—Philadelphia’s third and oft-forgot line, the Patco, was untested. What they found is that temperatures in the stations were significantly below the temperatures above ground. The Market–Frankford stations, for example, were less than 100ºF.

Just explore the rails…
Just explore the rails…

Of course that misses the 2nd Street station in Old City, but otherwise picks up all the Market–Frankford stations situated underground.

Then there is the Broad Street Line.

More rail riding…
More rail riding…

Here, I do have a question about why the line wasn’t investigated from north to south. It ran only as far north as Girard, stopping well short of north Philadelphia neighbourhoods, and then as far south as Snyder, missing both Oregon and Pattison (sorry, corporately branded AT&T) stations. The robustness of the dataset is a bit worrying.

The colours here too mean nothing. Instead blue is used for the blue-coloured Market–Frankford line and orange for the orange-coloured Broad Street line. (The Patco line would have been red.) Here was a missed opportunity to encode temperature data along the route.

Finally, if the sidewalk temperatures were measured at each station, I would want to see that data alongside and perhaps run some comparisons.

This is an interesting story, but some more exploration and visualisation of the data could have taken it to the next level.

Credit for the piece goes to Danya Henninger.

Public Transit of Yesteryear

For my frequent readers, it will be no big surprise that I am avid supporter of public transit, especially the railways. Consequently I was delighted when I read a non-Brexit piece in the Guardian yesterday that looked at public transit systems in several cities.

But it did so by comparing earlier plans or systems to those in existence today.

That's definitely one time I'd like to live in the past.
That’s definitely one time I’d like to live in the past.

Each design is slightly different and reflects the source material for the various cities. But I naturally selected the Philadelphia map. One of the biggest things to notice are the lack of trams/trolleys north of Girard and the addition of the River Line.

Credit for the piece goes to Jake Berman.

Similar Airspeed Patterns

Yesterday we looked at the isolation of the US and Canada in keeping the Boeing 737 Max aircraft in the air. Later that day, both countries grounded those aircraft. Today in the print edition of the New York Times the front page used significant space to chart the vertical speed of the two crashed aircraft.

They are remarkably similar…
They are remarkably similar…

It uses the same scale on the y-axis and clearly shows how the aircraft gaining and losing vertical speeds. I am not sure what is gained by the shading below the 0 baseline. I do really enjoy the method of using a chart below the airspeeds to show the periods of increasing and decreasing vertical speed.

Credit for the piece Jin Wu, K.K. Rebecca Lai, and Joe Ward.

The US Flies Alone

On Sunday, a Boeing 737 Max 8 aircraft crashed shortly after taking off from the airport in Addis Ababa, Ethiopia. This was the second crash in less than a year, since the another 737 Max 8 crashed into the sea shortly after taking off from Jakarta, Indonesia. And in the intervening months, there have been numerous reports to American regulators from pilots of problems with aircraft in flight. Unsurprisingly, international regulators have begun to take steps to protect their skies and their passengers from what might be an unsafe aircraft. American regulators, the Federal Aviation Administration, remains unconvinced.

Consequently, the New York Times put together a graphics-driven article that details just how extensive the global grounding of 737 Max 8 aircraft has been in the last 24 hours.

There's a lot more orange than blue.
There’s a lot more orange than blue.

It’s a route map to headline the article. And it shows that almost all aircraft on 737 Max 8 routes, except for those in Canada and the United States, have been grounded.

The rest of the article makes use of more maps highlighting the countries who civil aviation authorities have grounded flights and popular routes. It also includes a bar chart showing how many 737 Max 8 aircraft are in use with each airline and how many of those airlines have had their fleets grounded.

Overall, it’s a strong article that makes great use of graphics to illustrate its point about the magnitude of the grounding and the isolation of the United States and Canada.

Credit for the piece goes to Denise Lu, Allison McCann, Jin Wu, and K.K. Rebecca Lai.