Predict and provide
This post is a meditation on ‘predict and provide’. I’m no transport planner, so if I have missed some key point or principle, please accept my apologies in advance.
Officially, ‘predict and provide’ was killed off by the Government in 1998, when I was just 17. Yet the central philosophy of transport planning, across all modes, is to look at the journeys people are making now, extrapolate how many more of them are going to be taken in future and build infrastructure to accommodate the excess.
This isn’t just a roads thing: it is also the dominant philosophy for rail planning as well.
But isn’t it inevitable that this will result in a concentration of economic activity in fewer and fewer places?
This is exactly what has happened in the UK, with economic activity focused more and more on London.
“Derived demand”
I have a theory that the root of this problem lies with the idea of transport as a ‘derived demand’. Those of us with the misfortune to have studied economics at school were told that transport is a ‘derived demand’; meaning that people buy it not because they want transport as a thing but because it helps them get the things they actually want. I want groceries; I buy a bus fare to take me to the shop. I want entertainment; I buy a parking permit at the local cinema. I want income; I buy a season ticket to the office. etc etc etc.
People want services provided by the leisure, retail and hospitality sectors: transport is the means by which they can access these things.
As a result, it’s a short (but flawed) logical leap to say “If transport is the means by which people access the things they really want, we must make sure transport is provided where people want to go. So let’s see where people want to go, and then build transport to those places.”
That way of thinking inevitably takes you to predict and provide.
But don’t people primarily want to go to the places they can already get to?
I go where I can get
Predict and provide assumes that people have fixed destinations and will seek out those destinations regardless. But, do they?
I live in Walthamstow, and I suspect that people are disproportionately likely to work in the places that are easily accessible from Walthamstow. We have direct train lines to the City, the West End and parts of north London, but not to Canary Wharf or Stratford.
When the trains fill up, it’s tempting to spend money on enhancing capacity (that happened recently on both the Victoria line and the Overground). But wouldn’t it be better to instead create improved connectivity to other places? As an illustration, it would cost £15m to reopen the curve that links Walthamstow and Stratford. That would have resulted in an additional destination from Walthamstow, enabling more jobs and economic impact.
And, of course, it would by creating a new set of destinations, it would have meant that pressure was taken off the existing line - which solves the original problem!
To he that hath, more shall be given
If you add capacity to a rail line or road, you make it more attractive. That means more people will use it. And so more capacity is required again. The Victoria line in north London didn’t serve a single new location: it was created to relieve capacity pressure on the Piccadilly line and the Liverpool Street suburban lines. But, of course, prior to Covid it was almost full, and Crossrail 2 was proposed (also serving virtually no new stations). Why is the Victoria line full? Because people like me moved to Walthamstow because of the Victoria line. Had it never been built, people like me wouldn’t have tried to use it.
The result of this situation is that, in the postwar period, the following brand new lines have been built in London:
Victoria line
Jubilee line
Elizabeth line
And how many new stations will have been built on these three brand new lines? Um - four: Canada Water, Pimlico, Bermondsey and North Greenwich. Vast swathes of London don’t have access to rail services at all (e.g. Mount Pleasant, Walworth, Havering Park, Yeading, etc) but billions will have been spent improving capacity to the places that already have trains because that’s where the demand is.
Well, of course, that’s where the demand is. I mean, where else could it be?
Doesn’t our current way of doing things simply result in more and more transport to the same places?
New connections generate new demand
But when we do things differently and create completely new connections, we often find that those connections generate new demand.
Here are some case-studies for new connections generating new demand:
Lewknor Turn
No-one would have predicted the need to convert the B4009 outside Watlington into a linear car park. The reason it happened was that the Oxford Tube started serving the adjacent M40 motorway junction. They did so not because of any transport demand, but to pick up fuel duty rebate. The Lewknor turn off is 13 miles from the first stop in Oxford, meaning that this section of motorway running could qualify as local and claim the subsidy.
But once the service existed, people started using it. Lewknor Turn became a park and ride hub for the surrounding rural villages and people started moving into the area in order to commute on the Oxford Tube. The council widened the road to create parking along both sides and an entirely unpredicted (and unplanned) transport service was provided.
Lewknor. Who’s idea was this?
Golders Green
London was built by the railways. A prediction of the demand from Golders Green to central London in 1905 would have generated a low number, as the area was a pig farm. But, of course, by the 1920s, it was a densely populated suburb; thanks to the Underground, which arrived in 1907.
Gospel Oak to Barking
In some ways, the Overground project was something of a planner’s nightmare. The trains go not where any rational prediction might have required line to be built; but where under-utilised track happened to be. The Overground is a mash-up of two existing high-frequency lines, a couple of abandoned railway viaducts and several lines previously primarily used for freight.
One of the latter is the Gospel Oak to Barking line; one of those ‘nowhere to nowhere’ lines. Originally it ran from St Pancras as a commuter line but that purpose was rendered obsolete by the Victoria line and by the start of the century it had an unreliable two-carriage train shuttling every 30 mins; barely used. Today, it has a four carriage train every 15 minutes, a capacity increase of 400%. Where did they all come from? Well, this is the line that enables my family to go to Hampstead Heath. If it wasn’t there, we wouldn’t go.
M41 West Cross Route
This was literally an accidental motorway. Back in the 60s, there was a plan to build an inner “Motorway Box” right round all of London, following the routes of the South London, West London and North London rail lines. It was cancelled when it was belatedly realise that it would involve a degree of demolition unprecedented in London’s history. But not before a solitary 0.75 mile section of motorway was built in West London, completely isolated from the remainder of the box that had been due to be built north and south. It linked two roundabouts near Shepherd’s Bush and yet was a full-scale motorway with the gloriously pompous title of M41. It was downgraded to an A road in 2000 and substantially rebuilt ten years ago to create space for the new Westfield shopping centre. But despite its pointlessness as a dual carriageway and the fact that it basically didn’t go anywhere, it was kept as a dual carriageway because, of course, demand had now materialised and it was being used.
The A3220; formerly the M41 - the accidental motorway
These four examples are all examples of new connections generating new demand. But, of course, I’m not suggesting that we should just build transport infrastructure completely randomly. After all, there are better and worse places for new infrastructure. The Midland Metro (before Covid) had 0.57 million passengers per mile compared to 0.94 for the Nottingham tram, 0.69 for Croydon Tramlink and 0.69 for Manchester Metrolink. Why? Well, large swathes of the area served by Midland Metro are zoned for industry and the remaining housing is low-density.
Nevertheless, when Michael Heseltine was in charge of urban development, he received a business case for the DLR from the London Docklands Development Corporation. He was advised by his officials to reject it, as the demand to the Isle of Dogs could be better fulfilled by simply paying for free taxis for the handful of trips each hour. He ignored that advice - kick-starting development on the Isle of Dogs that then turned Canary Wharf into its own demand vortex that has now sucked in the DLR, Jubilee line and Crossrail.
So what should we build?
Maybe larger-scale investments should be about connecting as many people to as many other people as possible? HS2 kinda does this by accident. HS2 was created as a ‘predict and provide’ project, to increase capacity on the West Coast mainline, following predictions that even 11 car Pendolinos would burst by the end of the 2020s. But in the process, it will make vast swathes of northern England accessible to London for a day commute; spreading the prosperity of the capital on a national basis. Basingstoke is prosperous not because of anything great about Basingstoke but because of its proximity to London. It’s only proximate to London because of the speed of the trains: 200 years ago, Basingstoke was rural. HS2 will result in Birmingham being the same time distance from London as Basingstoke is today.
Maybe the test for transport investment should be ‘how many new journey opportunities does it create?’. When you have a situation of overcrowding, therefore, you don’t simply focus on increasing capacity but on providing alternative destinations.
Now, fairly obviously, road widening should never happen. The road will just fill up with traffic and need widening again. The only circumstances in which a road widening is justified is if it facilitates a move to lower carbon, more space-efficient transport. The A40 from Witney to Oxford is being widened to enable bus lanes. This is good, but it is also rare. Far more depressingly, in London, we’re building two new Thames River crossings. I’d obviously rather we weren’t building roads at all but one is next to the Blackwall Tunnel and the other next to the Dartford River Crossing. If we’re going to build a new Thames River crossing, how about doing it somewhere that doesn’t already have Thames river crossings?
But it’s not just about roads. Predict and provide has failed to reduce overcrowding on the Underground as the newest lines (the Victoria and Jubilee) are also two of the most overcrowded, as they generated their own new demand.
Maybe we need to stop worrying about predicting demand and fulfilling it with capacity and taking a bit more of a ‘build it and they will come’ approach?
