Transport maps have become too complex for our brains to understand, according to science

The Tokyo subway map. Easy, right? Image: Tokyo Bureau of Transportation.

As you may have heard (from us, approximately weekly), London's Underground map might just need a redesign. Perhaps adding colours to DLR lines would simplify things. What if the Circle and District lines were shaped like a little penguin? Maybe stations in the suburbs could be more evenly spaced?

But a new study suggests that transport maps not only in London, but in other big cities like Paris, Tokyo and New York, could simply be too big and complex for our brains to easily process - which means no amount of mapping and re-mapping would help.

This idea is based on the fact that, just as researchers estimate that we can only maintain between 100 and 200 friendships at once (this is known as Dunbar's number) there might also be a limit on how much information we can handle while figuring out how to get from A to B. 

Researchers from a variety of institutions concluded in their wittily named paper, "Lost in transportation: Information measures and cognitive limits in multilayer navigation", that we can only deal with around 8 "bits" (i.e. binary, yes/no decisions) at once, and are unlikely to read a map with more than 250 connection points with much ease. In doing so, they're treating our brains a little like you'd treat a computer: figuring out how much processing it can do at once without overloading and crashing. Or, you know, tearing up the map and getting a taxi. 

Part of the issue is that most global cities are now multi-modal - they have subways, buses, trams and even cable cars. While subway maps alone may be simple enough to understand, once you include different modes on the same map, "more than 80 per cent of trips" in New York, Paris and Tokyo are above the 8-bit limit. 

This slightly confusing graph shows that the maps featuring only subway systems (the dotted lines) mostly feature trips under the limit, while most trips on multi-modal maps (the solid lines) go over:

 

As a result, the researchers recommend maps which separate out layers so users can more easily understand them:

...traditional maps that represent all existing bus routes have a very limited utility. This result thus calls for a user-friendly way to present and use bus routes. For example, unwiring some bus-bus connections lowers the information and leads to the idea that a design centred around the metro layer could be efficient. However, further work is needed to reach an efficient, “optimal” design from a user’s perspective.

One example of better map design cited by the researchers are London's "spider bus maps", displayed in bus stops across the capital (you may have squinted at one in the early hours last time you got a night bus with a dead phone). They map out all bus routes proceeding from your current location, so you only see information relevant for your journey, plus they zoom in on the roads around the bus stop. Here's one for Harringay in northwest London:

Click to expand. Image: Transport For London.

This, however, doesn't help you much with longer journeys, or ones involving the Tube. The reality is that most trips in big cities require a combination of modes, especially if you're hoping to use the fastest route possible. As a result, the researchers say that transport in cities has simply become too complicated for our brains to handle on a single map: 

Human cognitive capacity is limited, and cities and their transportation networks have grown to a point that they have reached a level of complexity that is beyond humans’ processing capability to navigate in them. 


Even the attempt to map tangled city networks at all can seem futile, which is why the growth of transport apps and route planning websites is so crucial:

 Indeed, the growth of transportation systems has yielded networks that are so entangled with each other and so complicated that a visual representation on a map becomes too complex and ultimately useless...

The information-technology tools provided by companies and transportation agencies to help people navigate in transportation systems will soon become necessary in all large cities. 

So there you have it: using Citymapper doesn't mean you're lazy. It's just a necessary supplement to your cognitive processing power.  

 
 
 
 

Was the decline in Liverpool’s historic population really that unusual?

A view of Liverpool from Birkenhead. Image: Getty.

It is often reported that Liverpool’s population halved after the 1930s. But is this true? Or is it a myth?

Often, it’s simply assumed that it’s true. The end. Indeed, proud Londoner Lord Adonis – a leading proponent of the Liverpool-bypassing High Speed 2 railway, current chair of the National Infrastructure Commission, and generally a very influential person – stood on the stairs in Liverpool Town Hall in 2011 and said:

“The population of Liverpool has nearly halved in the last 50 years.”

This raises two questions. Firstly, did the population of the City of Liverpool really nearly halve in the 50 year period to 2011? That’s easy to check using this University of Portsmouth website – so I did just that (even though I knew he was wrong anyway). In 2011, the population of the City of Liverpool was 466,415. Fifty years earlier, in 1961, it was 737,637, which equates to a 37 per cent drop. Oops!

In fact, the City of Liverpool’s peak population was recorded in the 1931 Census as 846,302. Its lowest subsequent figure was recorded in the 2001 Census as 439,428 – which represents a 48 per cent decline from the peak population, over a 70 year period.

Compare this to the population figures for the similarly sized City of Manchester. Its peak population also recorded in the 1931 Census as 748,729, and its lowest subsequent figure was also recorded in the 2001 Census, as 392,830. This also represents a 48 per cent decline from the peak population, over the same 70 year period.

So, as can be seen here, Liverpool is not a special case at all. Which makes me wonder why it is often singled out or portrayed as exceptional in this regard, in the media and, indeed, by some badly briefed politicians. Even London has a similar story to tell, and it is told rather well in this recent article by a Londoner, for the Museum of London. (Editor’s note: It’s one of mine.)

This leads me onto the second question: where have all those people gone: London? The Moon? Mars?

Well, it turns out that the answer is bit boring and obvious actually: after World War 2, lots of people moved to the suburbs. You know: cars, commuter trains, slum clearance, the Blitz, all that stuff. In other words, Liverpool is just like many other places: after the war, this country experienced a depopulation bonanza.


So what form did this movement to the suburbs take, as far as Liverpool was concerned? Well, people moved and were moved to the suburbs of Greater Liverpool, in what are now the outer boroughs of the city region: Halton, Knowsley, St Helens, Sefton, Wirral. Others moved further, to Cheshire West & Chester, West Lancashire, Warrington, even nearby North Wales, as previously discussed here.

In common with many cities, indeed, Liverpool City Council actually built and owned large several ‘New Town’ council estates, to which they moved tens of thousands of people to from Liverpool’s inner districts: Winsford in Cheshire West (where comedian John Bishop grew up), Runcorn in Halton (where comedian John Bishop also grew up), Skelmersdale in West Lancashire, Kirkby in Knowsley. There is nothing unique or sinister here about Liverpool (apart from comedian John Bishop). This was common practice across the country – Indeed, it was central government policy – and resulted in about 160,000 people being ‘removed’ from the Liverpool local authority area.

Many other people also moved to the nearby suburbs of Greater Liverpool to private housing – another trend reflected across the country. It’s worth acknowledging, however, that cities across the world are subject to a level of ‘churn’ in population, whereby many people move out and many people move in, over time, too.

So how did those prominent images of derelict streets in the inner-city part of the City of Liverpool local authority area come about? For that, you have to blame the last Labour government’s over-zealous ‘Housing Market Renewal Initiative’ (HMRI) disaster – and the over enthusiastic participation of the then-Lib Dem controlled city council. On the promise of ‘free’ money from central government, the latter removed hundreds of people from their homes with a view to demolishing the Victorian terraces, and building new replacements. Many of these houses, in truth, were already fully modernised, owner-occupied houses within viable and longstanding communities, as can be seen here in Voelas Street, one of the famous Welsh Streets of Liverpool:

Voelas Street before HMRI implementation. Image: WelshStreets.co.uk.

The same picture after HMRI implementation Image: WelshStreets.co.uk. 

Nonetheless: the council bought the houses and ‘tinned them up’ ready for demolition. Then the coalition Conservative/Lib Dem government, elected in 2010, pulled the plug on the scheme. 

Fast forward to 2017 and many of the condemned houses have been renovated, in a process which is still ongoing. These are over-subscribed when they come to market, suggesting that the idea was never appropriate for Liverpool on that scale. 

At any rate, it turns out that the Liverpool metropolitan population is pretty much the same as it was at its peak in 1931 (depending where the local borough boundaries are arbitrarily drawn). It just begs the question: why are well educated and supposedly clever people misrepresenting the Liverpool metropolis, in particular, in this way so often? Surely they aren’t stupid are they?


And why are some people so determined to always isolate the City of Liverpool from its hinterland, while London is always described in terms of its whole urban area? It just confuses and undermines what would otherwise often be worthwhile comparisons and discussions. Or, to put it another way: “never, ever, compare apples with larger urban zones”.

In a recent Channel 4 documentary, for example, the well-known and respected journalist Michael Burke directly compared the forecast population growths, by 2039, of the City of Liverpool single local authority area against that of the combined 33 local authority areas of Greater London: 42,722 versus 2.187,708. I mean, what bizarre point is such an inappropriate comparison even trying to make? It is like comparing the projected growth of a normal sized-person’s head with the projected growth of the whole of an obese person, over a protracted period.

Having said all that, there is an important sensible conversation to be had as to why the populations of the Greater Liverpool metropolis and others haven’t grown as fast as maybe should have been the case, whilst, in recent times, the Greater London population has been burgeoning. But constantly pitching it as some sort of rare local apocalypse helps no one.

Dave Mail has declared himself CityMetric’s Liverpool City Region correspondent. He will be updating us on the brave new world of Liverpool City Region, mostly monthly, in ‘E-mail from Liverpool City Region’ and he is on twitter @davemail2017.