Tag Archives: congestion

Bridge Diet time

The latest from Streetfilms explains how everyone, especially motorists, can benefit from taking road space away from cars:

Boris Johnson promised to “smooth the traffic flow”.  It’s a vague policy which could be interpreted in any number of ways, and used to support a great variety of often conflicting policies.  I think when most people imagine a “smooth” traffic flow, though, they do not think of high motor vehicle speed or great motor vehicle capacity.  They think of reliable journeys.  Consistent journeys.  They could be reliably slow and consistently congested if those are the prevailing conditions.  And that’s fine.  The point of things being “smooth” is not to shove more people though the system in shorter times.  It’s to eliminate surprises.  A “smooth” flow means that deliveries leave the depot at the same time each day and always reach the shops on time; people get the same bus each morning and are never late for work.  Most people, I think, would interpret “smoothing the flow” as a move away from the impossible fantasy of solving congestion, to a new fantasy policy of reducing random one-off congestion incidents — of making congestion a little more predictable.  Businesses can plan for the predictable.

The biggest cause of unpredictable congestion is crashes.  Crashes are themselves frequently caused by excessive speed and complicated road layouts.  Road layouts that require lane-changing and lane-merging, especially.  Things like this:

Consider the southbound carriageway of this proposed TfL road design.  Vehicles from two roads feed into the carriageway and have to sort themselves into two southbound lanes and a right-turn lane.  The drivers of those vehicles will have to negotiate with buses that will be crossing all of the lanes from their left-hand-side bus stop to their own special right-turn bus lane.  They will need to be checking for the bicycles which have to share their lanes, and which may be wobbling out of the under-size bicycle lane (where it is provided); pedestrians at the crossings and islands; and bicycles which are dumped in the road from a perpendicular bike lane.  Certainly many of the drivers of those vehicles will choose to swerve around such obstacles, taking advantage of the raised 30mph speed limit, rather than slow down for them.  And after enjoying a couple of hundred yards with two lanes through which to meander, motor vehicles will all have to merge into a single lane — just at the moment that they are all racing away from a set of pedestrian crossing lights — because one of their lanes becomes a bus lane at the south end of the new layout.  All this high-speed lane changing and merging is a recipe for crashes.  Unpredictable congestion.

Indeed, even when it doesn’t result in crashes, the waves of braking that follow a lane change or merge still causes “lumpy” traffic.  (Tom Vanderbilt’s blog and book explain the phenomenon and its subtleties excellently.)

I would suggest to TfL, and to its chairman, that a road design like this could conflict with the mayor’s election promise to “smooth” the traffic flow.  But I know they would come back with the perfect solution.  They would remove the bus lane restriction on Blackfriars Bridge.

In the meantime, we have one day left to contribute to the “engagement” on this road design.

Engineering, psychology, and a bus on stilts

This week I’m trying to clear up the loose ends of threads I began and never finished, and get rid of some of the draft posts that I started but never polished…

Last week I posted about tracked hovercraft and straddling buses — a tongue-in-cheek look at how through the ages engineers have proposed ever more overcomplicated engineering solutions in an attempt to manage our out-of-control transport problems.  I assumed that my learned readers would get the point without labour.  WordPress.com very kindly picked it as one of their daily front-page features, though, which led to it receiving around 4,000 spam comments, including several dozen along the lines of “wow that bus looks awsum and wood solve all our problems make one for america!!!?! (p.s. here’s a link to my blog!!!11!)”.*

Well, actually my guess is that the straddling bus will be just another absurd transport solution that fails to achieve the things that it is designed to achieve.  The stated purpose of the bus is not to get cars out of its way, it is to get the bus out of cars’ way: the designers complain that the frequent stop-starting of buses means that they hold up the traffic behind.  It will probably fail to achieve much in the way of making car drivers’ lives easier because the designers are obsessed with engineering and don’t consider Motorist behaviour.

Here are a couple of random fascinating psychology factoids.  I wonder to what extent the bus backers have considered them in their models?

  • When you make road lanes just a little but wider — as you will surely need to do if you are to accommodate the bus safely — people drive faster.  They’re not doing it deliberately or rationally, perhaps not even consciously, they just do it.  It feels right.
  • Drivers slow down for tunnels, and things that feel like tunnels — tree-lined avenues and close high walls.  Even if there’s nothing telling them to, and no rational safety reason to do so.  They just do it.

The cause of traffic jams is traffic.  Too much of if, behaving erratically.  We like to pretend that it’s bad engineering, because we can always fix engineering by replacing it with some different engineering.  And we like to pretend that it’s not the volume of traffic and the behaviour of drivers, because acknowledging this would mean giving up hope that one day the traffic jams will magically be solved.  But that’s the way it is: too many cars, too badly driven.  The straddling bus will probably not help congestion — at least, no more than a conventional bus on a conventional bus lane — because it will change driver behaviour in a way we can’t easily predict, but which (as described) will likely involve them slowing down and speeding up in chaotic waves as the bus passes them and they pass the bus.  It doesn’t sound like much, but these effects have a habit of amplifying themselves: the traffic between lanes will cease to be smooth, so cars will be changing lanes more, and this lane-changing contributes further to slowing things down, and also greatly raises the risks of accidents occurring.

Perhaps that effect will be marginal given all of the other existing complications and currents in the traffic flow.  Perhaps we’ll see other interesting unforeseen behaviour changes in the Shenzhen trial.  All that we can say for sure that everybody will be predictably surprised when drivers don’t behave in a simple rational manner.  Just like they were the last ten thousand times the solution to congestion was discovered.

The main reason the bus will fail, though, is the same reason that all urban roadspace provision schemes fail: create a new space for cars to drive in, and an equal or greater quantity of car journeys will be created to fill that space.  The cause of traffic jams is too much traffic.  Double the capacity for traffic and all you’re doing is doubling the size of the traffic jams.

Put a conventional bus on a conventional (parking and taxi enforced) bus lane.  It’s easier.

* Not that I’m not grateful for all your valuable contributions to our discussions ;)

Memo to Philip Hammond: Hoverboards project

Continuing the 1963 Buchanan Report on the future of transport in towns, over the page:

A development which may offer a more direct challenge to the motor car, assuming the problem of noise can be overcome, is the air-cushion craft.  It seems to give scope for development of a small personal machine, useable perhaps eventually on ordinary pavements as a substitute for walking.  Yet it may be questioned whether it would really take this form, whether the urge to put a perspex cover over it for weather protection, to use it at higher speeds, to add extra seats, and to affix luggage containers, would not soon convert it into a motor car in all respects but the possession of wheels.

[…] It may have a different source of motive power so that it is no longer strictly a motor vehicle, it may be quieter and without fumes, it may be styled in some quite different way, it may be produced in smaller forms, it may be guided in certain streets by electronic means, it may have the ability to perform sideways movements, but for practical purposes it will present most of the problems that are presented by the motor vehicle today.

These days if you drop a criticism of car addiction into a conversation somebody will be there with a defence of car use: you could have the bigger carbon footprint.  Somebody driving their compact fuel efficient car to the shops once a week might have a smaller carbon footprint than somebody taking daily long-distance rail trips.  Congestion?  Sure, but that won’t make much of a difference to their carbon footprint.  They might drive into somebody?  Sure, but that won’t make much of a difference to their carbon footprint.  Particulate pollution?  That’s not a greenhouse gas.

Everyone seems to have forgotten that there were already multiple major problems with our transport and town planning long before we discovered our CO2 problem.  We need a solution to them all, not an excuse to ignore all but one.

(With a tip of the hat to Carlton Reid, whose joke I’m stealing.)

Weekly War Bulletin, 2 Oct

The exciting news of the week is that petrol head secretary of state for transport Philip Hammond has ended the War On The Motorist by announcing that John Prescott’s M4 bus lane will revert to an all-traffic lane.  Never mind the fact that this will do nothing to improve the actual journey times of Motorists, because a bottleneck further down the road determines its overall capacity.  This is politics, after all: no room for evidence in deciding policy.  Interestingly, this news has pitched private Motorists against cabbies, with desperate attempts to justify the presence of taxis in bus lanes.  Despite being the most universally hated road users in London, the taxis could at least rely on the politicians — who in turn rely on taxis to avoid mixing with the proles on the buses — for friendship and a free ride down the bus lane.  Now even Phillip Hammond has deserted them and told them to sit in the jams with all the other non-public transport.

A meaningless PR “study” finds that Clapham and Wandsworth have the most congested roads in London.  The AA say the problem is roadworks and a lack of “money thrown at the problem”.  Not too many cars, then?  The Evening Standard commenters actually fill me with hope for once:

What the lobbyists fail to mention though, is that there are simply too many cars in London. Why is that simple fact not mentioned?

You could a south London version of the Westway and it would still end up gridlocked. Road works don’t help in the slightest but it’s just a distraction from the true cause.

Of course, they won’t mention that, because in UK plc any attempt at tackling this problem is a “war on the motorist”.

- Ashley, Camden, 01/10/2010 13:57

The government has stumbled upon a clever scheme to keep good news about transport funding flowing: regularly announce that Crossrail funding is safe.  Everyone will forget that you already announced that last week, and the week before…

But Norman Baker, Minister for Pedestrians, Cyclists, Bus Passengers, and Other Unimportant Transport Users, has this week announced that Bikeability will not be allowed to go up in flames with the bonfire of the quangos.

The Met have expanded their Cycle Task Force.  There are some hilarious and presumably sarcastic comments from the mayor’s transport advisor: “the Cycle Task Force is a fundamental part of the cycling revolution the Mayor has delivered in London,” and “however there is always more that can be done to make London the best cycling city in the world…”

A hit-and-run killer dragged a woman under their car for a mile, around Belsize Park.  Meanwhile, a killer delivery driver in the city gets a suspended sentence.

Driver re-education courses, for careless driving and law breaking, won’t work.  Not that the £1000 fine given to hardened criminal Katie Price for careless driving and apparently texting while driving a horsebox on the motorway will.

The government has published its Manual For Streets, advocating shared space for the nation’s high streets.  Look forward to some of the ideas being implemented in the street regeneration plans that have been announced for Belfast, Bournemouth, Prestatyn, and Reading.  Also in the regions, Clay Cross in Derbyshire has been given conservation status; and Aberystwyth gets more money to spend on green transport (interesting that the BBC illustrate the story with a “cycling forbidden” sign).

Work begins on the next couple of “superhighways”.  Interestingly, they’re the ones to serve, erm, the two parts of town that already have superhighways.

Going places is going to continue to get more expensive.  (Unless, erm, you walk or cycle there?)  Lets all blame the government and ignore the rising prices of increasingly hard to obtain oil.

TfL aren’t very good at replying to freedom of information requests — or are good at procrastinating on them, anyway.

French towns are replacing their bin lorries with horse-drawn recycling carts.  This is still the least absurd modern transport solution I’ve heard all year.  The robotic high-density deep-underground car park in Birmingham being one of the many absurdities indicative of late-phase chronic car dependency.

South Wales are making more shock adverts about careless and dangerous driving.

Drivers who pass their driving test are safer than the ones who don’t.  Thanks, Professor Obvious.

Stratford Central Line westbound has an exciting revolutionary new platform where the doors can open on both sides of the train.  Magic.

Nobody is stealing hire bikes.  Well, five.  Of more concern is that the Independent have adopted the Evening Standard‘s awful name for them.

Segway owner accidentally rides Segway over cliff, falls to his death.

Smelly cyclists not welcome in New Forest tea shops.

Kingsland cyclist muggers arrested.

Anti-social Motorists in Guidford “block one-way system“.

Lorry collides with M6 at Coventry.  Car collides with M11 in Essex.  And the National Arboretum has opened a memorial to those who have died in the name of Motorways.

And a house has collided with a 206 in Hampshire, a Cafe has collided with a Vauxhall in Aberdeenshire, and three houses collided with a car in Sunderland.  Meanwhile a bollard has collided with a Nissan in Derbyshire.

Luxury cars torched in Dundee and Devon, and a “spate” of scratched cars on the IoW.

Australia have launched a National Cycling Strategy.  Lets hope they’ve looked at Europe and noticed which country’s strategy has succeeded and which is failing, and picked the one that works.

Finally, Google Street View now covers Antarctica.

Some moments of zen: Old man rides a bikeBear rides a train.  And, man carries carpet on mobility scooter — how irresponsible: that 8mph carpet could have been a danger to the poor Motorists…

“It’s a danger to himself and a danger to other motorists. If someone wasn’t careful, they could’ve hit him off and he could’ve got seriously hurt and his family wouldn’t like that.”

If you build it they will come

On the London Cyclist thread “is there anything super about the Cycle Superhighways?,” we hear Chinese whispers on the reason why TfL decided against making real superhighways and instead came up with the overpriced and failed PR exercise that are the blue lines on the side of the road:

“TfL said the routes are simply not being used frequently enough to warrant separation of traffic.”

and,

Boris, when asked why the Superhighways are not segregated, always says “There is just not room on London’s roads”.

Whether Boris used one or both of these excuses, he is wrong.  The reason he is wrong is Transport Economics 101 stuff — the sort of thing that even amateurs like us understand.  Simply, the demand for transport — and especially the demand for a specific mode of transport in an area with competing modes — is extremely flexible, and easily adjusts to supply.

People like to go places.  If you give them fast and affordable railways, they will jump on the train to the seaside.  If you give them fast and affordable roads, they will drive their car to work.  If you give them budget airlines, they will herd into planes to southern Europe.  A new transport mode releases latent demand: previously, though they would have liked to have gone somewhere, they chose not to because it was too difficult or expensive.  And it induces demand in other ways: a new road creates car journeys by allowing small local shops and services to be closed and merged into large centralised versions that people have little choice but to drive to, or by removing the incentive for efficient means of transporting goods, or by making it feasible to develop residential suburbs and new towns far from centres of employment, etc.

This is why in densely populated places like the UK, building a new road to solve one problem always creates another before long: the new road makes driving easier and cheaper, so more people drive and they drive further and more frequently, putting additional pressure on all the existing infrastructure surrounding the new road.  We could bulldoze corridors through the cities and pave the whole countryside, build ten times the road capacity that we currently have, and the road network would be just as overloaded as it is now.  This we already knew.

What is less well known is that the reverse is just as true.  Make it more difficult to drive somewhere and people will not drive there.  Make taxis sit in traffic jams instead of subsidising their industry by allowing them into bus lanes, and their fares will take the train instead.  Make it more expensive for goods vehicles to get into central London and the businesses and organisations that are based there will stop being so wasteful with goods.  Impose airport taxes on budget flights to the continent and people will realise that they can have an equally appalling stag night somewhere nearer home.

Take away a transport route and our remarkably robust network copes just fine.  A sudden emergency causes disruption because people aren’t expecting it; but sufficiently well publicised road works have a far more modest impact because people adjust their plans around them — take a different route, move their journey to an off-peak time, or do something else instead.  Permanently closing a whole road is even better tolerated still: such closures do not leave the surrounding roads gridlocked, at least, not in the long term.  People shift modes and shift behaviours; and eventually, all of the businesses and development patterns that had adjusted to a world in which everybody drove down that road will happily adjust back to one in which they don’t.

The amount of road space that we have now is essentially arbitrary: it could go up or down without making the slightest difference to the traffic jams its users moan about.

So it is not true that our streets are too small to accommodate dedicated cycling facilities.  Our streets are already too small, and will always be too small, to accommodate even a tenth of the potential for private motor-vehicle use, and we cope with that situation.  The road network copes with this situation because nine out of ten Londoners are quite aware of the fact that trying to drive a car through town is an absurd thing to do, and they don’t do it.  Taking away a little bit more will make a negligible difference because a few of the more stubborn Motorists will wake up to the fact and the volume of traffic will adjust accordingly.

And it’s not true that there is no demand for segregated facilities, and anybody who says there isn’t must be living in a fantasy land.  Pick a random non-cycling London commuter and ask them about cycling: more often than not they will tell you that would love to be able to replace their horrible bus journey with a bike ride.  But ninety-nine out of a hundred of them will tell you that they don’t do so because the roads aren’t safe, and there’s nothing to stop a truck driving into them.  Not because they’re afraid that they might get sweaty, or because it occasionally rains, or because they don’t know how to use a spanner, or because they’ve never heard of cycling before.  Entirely because there is no infrastructure that is perceived to be safe.  Cycling has a modal share at the lower end of single figures; it could plausibly account for a third or more of commutes.  Provide fast, capacious, sensible, joined-up and conspicuously safe infrastructure and you will unleash the vast latent demand for cycling.

If you build it they will come.  The only reason not to that Boris has left is to protect his credentials with the primarily non-London Motorist Tories who he will one day want to vote for him to be prime-minister.

–Joe