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.  


To make electric vehicles happen, the government must devolve energy policy to councils

The future. Image: Getty.

Last week, the Guardian revealed that at least a quarter of councils have halted the roll-out of electric vehicle (EV) charging infrastructure with no plans to resume its installation. This is a fully charged battery-worth of miles short of ideal, given the ambitious decarbonisation targets to which the UK is rightly working.

It’s even more startling given the current focus on inclusive growth, for the switch to EVs is an economic advancement, on an individual and societal level. Decarbonisation will free up resources and push growth, but the way in which we go about it will have impacts for generations after the task is complete.

If there is one lesson that has been not so much taught to us as screamed at us by recent history, it is that the market does not deliver inclusivity by itself. Left to its own devices, the market tends to leave people behind. And people left behind make all kinds of rational decisions, in polling stations and elsewhere that can seem wholly irrational to those charged with keeping pace – as illuminted in Jeremy Harding’s despatch from the ‘periphery’ which has incubated France’s ‘gilet jaunes’ in the London Review of Books.

But what in the name of Nikola Tesla has any of this to do with charging stations? The Localis argument is simple: local government must work strategically with energy network providers to ensure that EV charging stations are rolled out equally across areas, to ensure deprived areas do not face further disadvantage in the switch to EVs. To do so, Ofgem must first devolve certain regulations around energy supply and management to our combined authorities and city regions.

Although it might make sense now to invest in wealthier areas where EVs are already present, if there isn’t infrastructure in place ahead of demand elsewhere, then we risk a ‘tale of two cities’, where decarbonisation is two-speed and its benefits are two-tier.

The Department for Transport (DfT) announced on Monday that urban mobility will be an issue for overarching and intelligent strategy moving forward. The issue of fairness must be central to any such strategy, lest it just become a case of more nice things in nice places and a further widening of the social gap in our cities.

This is where the local state comes in. To achieve clean transport across a city, more is needed than just the installation of charging points.  Collaboration must be coordinated between many of a place’s moving parts.

The DfT announcement makes much of open data, which is undoubtedly crucial to realising the goal of a smart city. This awareness of digital infrastructure must also be matched by upgrades to physical infrastructure, if we are going to realise the full network effects of an integrated city, and as we argue in detail in our recent report, it is here that inclusivity can be stitched firmly into the fabric.

Councils know the ins and outs of deprivation within their boundaries and are uniquely placed to bring together stakeholders from across sectors to devise and implement inclusive transport strategy. In the switch to EVs and in the wider Future of Mobility, they must stay a major player in the game.

As transport minister and biographer of Edmund Burke, Jesse Norman has been keen to stress the founding Conservative philosopher’s belief in the duty of those living in the present to respect the traditions of the past and keep this legacy alive for their own successors.

If this is to be a Burkean moment in making the leap to the transformative transport systems of the future, Mr Norman should give due attention to local government’s role as “little platoons” in this process: as committed agents of change whose civic responsibility and knowledge of place can make this mobility revolution happen.

Joe Fyans is head of research at the think tank Localis.