Monday, 24 November 2014

Sigh

Even with the polish from last week's post still barely dry, there came a funding announcement from Transport for London for some "bright ideas to radically improve London's streets".

This is the Mayor's "Future Streets Incubator Fund" which was announced in March to the tune of £1.8m. Read the full details for yourself, but the concept was:

From ideas such as temporary public plazas to pop-up street sporting activities, the 'Future Streets Incubator Fund' will help convert more of London's streets into spaces where people can socialise and interact.

There will also be a focus on creating new, greener spaces, boosting sustainable transport, testing new street layouts and alternative ways that roads and streets can be used.

The Mayor and TfL are looking for creative pilot scheme submissions from local boroughs, Business Improvement Districts (BIDs) and community groups in order to award the substantial funding over the next three years.

The idea seems to have come from the Roads Task Force which provides an update in its report from March of this year (p17).

Now £1.8m is small beer for the Mayor when compared to the wider budget he controls and this is funded at £600k per year for three years, so relatively modest. Funnelled through TfL, we can surely look forward to some real transport innovation;

The fund will champion innovation and will be a great way to temporarily try out new street layouts using low-cost measures.

The full TfL webpage can be viewed here, but the details are rather sketchy and so I will reproduce them below. Before I continue, there are a couple good ideas (in my humble opinion of course), a few which have been done before in the UK (so where is the innovation?) and some appear to be complete cobblers (yes, in my view of course, you are welcome to disagree).

As more details emerge, then I may well have to change my mind, but today, I call it as I see it. One other thing to note is that these have not just been punted in, the process involved organisations giving outline details to TfL so that feedback could be given before they were invited to formally submit bids. In other words, TfL considered the proposals to have merit before the bids were made. 

So, at last, I get round to the schemes - descriptions in italics, my comments underneath each one.

Simultaneous Green
In partnership with the London Borough of Richmond upon Thames.
A continental-style simultaneous green signal for cyclists will be trialled [sic] using advanced technology. The junction will detect the presence of cyclists before giving them a dedicated green light in all directions during which they can cross along their desire lines.

Well, it will be no surprise that I welcome this, but why it wasn't included on TfL's off street trials, I will never know. We don't get know if this will be at a "live" site or as another off street trial somewhere in Richmond. There is no detail on whether this will be as part of protected cycle lanes or a pre-green fudge from ASLs. It seems a bit random as this would not be a borough which springs to mind for being at the cutting edge of cycling. Still, they have now massively raised my expectation, so let's see where it goes.


The Bounceway
In partnership with Architecture for Humanity.
The Bounceway will be the world's longest urban trampoline. This iconic and inclusive new public space in the heart of London will boost fitness and fun, and provide a novel form of transport where the journey is the main event. The trial will be part-funded by a crowdfunding campaign set to launch in late 2014.

Pardon. What the hell is this? "A fun and novel form of transport"? TRAMPOLINES ARE NOT TRANSPORT. Seriously, TfL, what the hell are you doing? Do I really need to criticise this? I found this link after a bit of delving - it has a link to Architecture for Humanity and so I reckon this is the concept. Perhaps this is intended to be a public art idea to promote discussion, but there is no way this should in anyway linked to a TfL-run transport project. Nonsense.


Flexi-lane
In partnership with the London Borough of Bromley.
A flexible lane using intelligent road studs and dynamic signs will switch between loading bays, parking and a bus lane throughout the day. The trial will allow road space to be used more efficiently and the road studs will monitor traffic flow to help improve road reliability.

Well at first glance it seems reasonable. But wait. We can already do this. Bus Lanes can be part time and we can put parking and loading bays in them to be used outside of bus lane operational times. OK, there may be something new here, but it looks like a solution looking for a problem.


Colourful Crossings
In partnership with Better Bankside.
An artist will bring graphic designs to pedestrian crossings and the carriageway on Southwark Street in Bankside. The crossings will show how art can change people's perceptions and use of junctions and bring the street to life.

You what? How can "art change people's perceptions and use of junctions"? Looks like an entire barrel of special polish to me. Southwark Street needs more than graphic designs at crossings and junctions, believe me.


E-permits
In partnership with the City of Westminster.
E-parking permits will communicate with sensors embedded in disabled resident parking bays to provide better, more targeted enforcement of parking regulations and ensure kerbside access for Blue Badge holders. E-permits have the potential to be used in other types of bays to improve parking management across the Capital.

You have to giggle really, it is no surprise that Westminster has a parking scheme! What is interesting is the blurb confirms that the idea is not innovative as the concept has been used elsewhere. I assume the idea will use road sensors which detect parked vehicles along the lines of the scheme Westminster already runs. In this scenario, I assume the sensor will detect the permit holder's vehicle using a tag in the vehicle. If a vehicle without a tag parks, then enforcement will be alerted and they can turn up and nick the offender. But, why can't they just get on with it for their disabled residents now? 


Parklets
In partnership with Team London Bridge and the London Borough of Ealing.
Parking bays will be repurposed to provide amenities such as seating, canopies, greenery and cycle parking. These living spaces will give streets a cost-effective makeover and improve the environment for pedestrians and cyclists.

Well, cycle parking in parking bays is old hat. It has been done by Hackney and elsewhere, plus others are looking at the idea. Change parking bays into seating and parklets? There is no innovation here, we can move kerb lines now.


School Streets
In partnership with the London Borough of Camden.
Streets around three schools will be closed at both the start and end of the day to promote healthy, active travel and make walking safer and easier for children. The trial will encourage people to make small changes to how they travel and has the potential to make streets more lively and fun.

I think Scotland might get there first with its parking ban, although this idea seems like a ban on driving. Not sure there is much innovation here as this is a similar concept (I guess) to play streets. We have had these for years and there are quite a few schemes in London already. I assume that this will be a series of roads closed, perhaps as "pedestrian zones" during specific times of the day. The interesting thing here will be whether residents are also banned from driving though these streets as well or if problems get shifted elsewhere! Yes, might be an interesting one to watch!


Tunnel Vision
In partnership with the Brick Box.
A blighted underpass will be transformed using interactive new lighting design and resilient, low-maintenance technology to improve safety and security for pedestrians.

This mob have form (assuming I have got the right people of course) - their website talks of a temporary scheme in Thamesmead, although I guess this must be a permanent way of dealing with a "blighted underpass". Which underpass and why is it blighted would be my first questions. I suspect that the answer is not to shine lights at it. 


Sight Line
In partnership with the London Borough of Islington and the Royal College of Art.
Improvements will be made to road work barriers to help visually impaired people navigate around them. Features include tactile arrows, high contrast signs and real-time digital location information.

OK, this is interesting and could be really helpful to many users trying to get through roadworks. I just hope they realise who will be installing temporary barriers as they don't always get it to perfection!


Cloud Consolidator
In partnership with the Fitzrovia Partnership.
An online purchasing system will be introduced to reduce the number of freight vehicles by combining common orders and deliveries for local businesses.

I am not sure if this is particularly new as deliver consolidation schemes were being looked at for the Olympics. However, the idea makes sense as it could be cheaper for the individual businesses and reduce lorry movements. I await the scheme with interest.


So, there you have it. The Mayor and TfL have run out of ideas and so after an exhaustive search, we have the cream of London's transport and streets ideas. To be fair, there are a few which are worthy at first glance and might go interesting places.

The trouble is, these sort of funding streams bring the showman designers out of their rubber-coated rooms. Then we get trampolines suggested as modes of transport. Sigh.

Wednesday, 19 November 2014

You Can't Polish A Turd...

Not a very professional post title I know, but attempted turd polishing is everywhere and besides, it is one of my favourite sayings which I use to counter some of the management-speak cobblers often used to justify public realm schemes.

A couple of trees which might help reduce speeds when they get a
bit bigger, plus they look nice in a relatively quiet side road.
First on my faecal-flossary hit list; doomed to my smallest Room 101 if you will, is the street tree. Now I am not some evil destroyer-of-trees, I love trees. Especially fruit ones. Especially if I can ferment the fruit!

Trees can transform a street from a concrete jungle to a minor oasis. They can be used to visually narrow a street (to slow drivers) and on the whole, trees seem to make people happy. Street trees do have a service life like any other kit and so they need to be the right tree. They need replacing from time to time and sometimes, they might need to come out to allow something to be built.

My ire is not with the tree, but the people behind turd polishing projects which try and take an urban motorway, stick a few trees in and then call it a "City Boulevard" in an attempt to suggest the route now has importance as a "place", rather than for movement. I am not against planting trees in this kind of place per se, but to try and suggest the route is anything other than an urban motorway is disingenuous.

The Mayor of London has been sticking in a few trees in recent years as part of his 2012 election manifesto. As the 5th point out of 9 of a "plan for a Greater London", planting trees was more important than transport (8th). Why do we want more trees I hear you scream? Well, there is a helpful set of reasons which I suppose are fair aspirations on their own, but given the number of new trees involved it really does seem to be window dressing to me. Tackling climate change by planting a few trees is as ridiculous as spending £30bn on a 22 mile tunnel around the Capital - I guess the Mayor likes to present schemes to specific audiences, depending on their views.

You also hear about schemes to "greening the <insert name of massive road>". These schemes try and use trees and other landscaping which are the "low hanging fruit" which can make streets more liveable (my own bullshit wording). In reality, it is about smearing a veneer of green space over what remains traffic dominated toilets where nobody would want to sit eating their lunch watching the lorries thunder by.

The Embankment in Westminster with the traffic turd flushed away
for one magical day a year.
Then we have "special events". Take the Ride London Freecycle. Please don't get me wrong, it is a cracking day out with the kids and it gives a glimpse to how a city could operate. 

The problem is that it is just one day a year, with temporary road closures trying to polish the turd which is cycling in Central London. The elephant in the room (now doubt fouling himself) is that with things like this we are trying to kid ourselves that cycling is for everyone in our cities, when in truth, once the road closed signs are thrown back onto the lorries, you are on your own (so long as you have your wits about you of course).

Paint makes it better.
How about 20mph speed limits? What could be wrong with those? Again, I am a fan and I would love them to be the default in urban areas. In the last few months, I have cycled around the City of London quite a few times and recently, most of it had a 20mph speed limit imposed. Do I feel any safer now? Of course not. The City has gotten out its road marking crews and tried to paint the turds into slowing down.

I am sorry, I also have to have a pop at other places looking to impose 20mph limits in this way. Unless the nature of the streets are changed, then we are still asking people to walk and cycle around heavy traffic (flow and size). Have you seen York Way on the Islington-Camden border?

We might get there in time if more urban areas adopt a 20mph speed limit in the absence of leadership from the Government; and if it becomes the norm. However, many places with this limit are still awful, despite the trees.


Well at least they are not cycling on the footway, this is a single
surface shared-space after all. Mind you, nobody is having a picnic
where the traffic is running.
Next, how about some multi-million pound, grand-master, stool-shining? I bring you Exhibition Road (yes, London again). 

If the traffic wasn't there (and it kind of isn't at one end which has restricted movements - pun intended!), then it would be a great setting for the world-famous museums. Instead, it remains a traffic-choked Central London rat-run and car park for the lunatics who run private cars slap bang in the middle of a city of 8 million people. If you walk up the street, the footways are crowded and people don't "share the space" with the cars, lorries and buses, unless they are feeling particularly brave (shared space will be a future post).

Finally, we have Seven Dials in London's Covent Gardent. This is almost one of my favourite London places at the moment. Interesting shops, a layout to give a road safety auditor stomach cramps, 300 years of history and a great atmosphere. It is almost one of my favourites, but it is ruined by black cabs and delivery vans pelting through the space, heedless of the pedestrians milling about. There are also the parking bays around the area which take up space which could be used so much more effectively (note the car-shaped bike rack which uses parking space more efficiently).

In this case, the turd polishing is more subtle, it is the way in which the place is celebrated as a wonderful place to visit while conveniently ignoring that it is yet again ruined by the people driving through it - I am not referring to the people who need to be there to make a delivery, but the rat-runners trying to avoid the traffic-choked main routes of Theatreland.


It is almost a nice place.
Turd polishing happens at so many levels and in so many ways that you could probably apply the concept to any argument to make your point. In my case, I am trying to show that the common denominator is that we are always trying to hide or ignore the fact that so many of our urban areas are utterly ruined by (often through) traffic. If it is an arterial road, then perhaps we need to accept it for what it is and either provide alternatives for people to avoid it as pedestrians and cyclists, or do a proper job and change it for ever by giving people real protection from traffic.

If we have traffic choked residential streets or places like Seven Dials, the answer is not to slap down some 20 roundels on the road and hope for the best, it is to filter out the through traffic in conjunction with a lower speed limit.

All too often we think that a bit of fancy paving and some trees will do the trick when it won't. Of course you can't polish a turd, but you can roll it in glitter.

Saturday, 15 November 2014

The National Funeral For The Unknown Victim Of Traffic Violence

Today I joined all sorts of people in a walk through the West End of London.

Organised by Stop Killing Cyclists, the walk was in protest to highlight the toll on Britain's streets caused by motor traffic. Here are some photos, you don't need opinions from me.


















Monday, 10 November 2014

The Road To Where?

I know it must come across as slightly perverse, that as a highway engineer and (sometime) driver I often speak out against road building. But, like many people my views have been shaped by experience.

A am a civil engineer by training and a highway engineer by specialism and so I could understand any confusion. I am not anti-car or anti-driver, I just want our highway networks to be arranged so that people have genuine choice and I am afraid that yet again, the Conservative/ Liberal Democrat Coalition leave me utterly cold with the Prime Minister's promised £15bn splurge on road building.

Of course, he was speaking at the Confederation of British Industry (CBI) conference today which is a pro-roads audience. I cannot quite work out if this is £15bn of new money, or a reannouncement, but Cameron and his mate Osborne have form. Labour has had a pop, but reading between the lines, it seems that they are unhappy with road schemes cancelled by the ConDems - frankly, I cannot tell the difference any more.

The road-building is within England's Strategic Road Network which is comprises motorways and Highways Agency operated trunk roads (Wales and Scotland have their own arrangements). Highlights include;
  • Legislating to secure long-term funding certainty. 
  • Delivering a huge programme of investment in our road infrastructure.  
  • Transforming the Highways Agency into a legally separate company. 
  • Introducing a roads investment strategy – backed by legislation. 
Making the Highways Agency (HA) a company is interesting. It will be government owned and be subject to a regulator and watchdog (Office of the Rail Regulatory and Passenger Focus). The cynic in me wonders if this is a set up for future privatisation or to keep stuff off the government's accounts. I have yet to read anything which convinces me that it is a good idea. Linked with the changes to the HA is apparent certainty of funding backed by legislation. Of course, legislation and funding can be changed.

Many of the road-building schemes are to deal with "pinch points" as well as increasing capacity. I think most people with a passing interest in this blog understand that predict and provide for roads has been discredited and that those forecasting traffic have got it totally wrong on the national scale. It is about a policy which assumes road building stimulates economic growth and that is why the CBI was interested.

I remember the M25 being built out in the east as when I went on a school trip to Hobbs Cross Farm (which is close to the junction with the M11) the road was still under construction (must have been at the start of the 1980s). Since it being fully opened in 1986, it has had capacity added to it and in 2012, the eastern section went from 3 lanes to 4 (with lane gain/ drop in places). I used the Dartford Crossing daily from 1998 to 2004 and my memories and experience bear out that every time capacity is added, it fills up. 

My 6-year stint was at a job (which was great by the way) which was pretty much impossible to by public transport - which is the often given as the reason for driving. Of course, had the M25 not been there, then it would be highly unlikely that I would have applied for the job in the first place - access to labour markets/ work is often cited as a reason for the Strategic Road Network (and freight as well). Of course, look at how public transport in London has and continues to provide access to labour and work!

I don't envy anyone who uses a congested motorway or trunk road, but you have to wonder where it will all stop. It is all very well adding capacity to these roads, but there are further knock-on effects in the areas around motorway and trunk road junctions which bear the brunt of traffic when there is a problem. There is also the issue of what to do when these big roads fizzle out as they hit towns and cities - the traffic has to go somewhere.

We get rumblings about road pricing from time to time as a way of managing demand, but I am not convinced. While it will encourage some people to change their journey times (if their jobs allow it), many people will be stuck with the choice of paying more of their income on travel or getting another job. Like the railways, peak times on the roads (when most people go to work) will be for those who can pay. Everyone else will be priced off and if still driving, the areas which the trunk roads and motorways bypass will become the new bypasses for those who can't, or won't pay. The problems associated with traffic on local and residential streets will also get worse.

The 2013-14 spend for the UK Government was forecast to be £720bn. £15bn is 2% of that sum, earmarked for 100 roads projects. Imagine what could be done for active travel if that was spent in the UK's top 15 towns and cities?

Tuesday, 4 November 2014

Traffic Signal Pie: A Midnight Feast (For Some)

Richard Tracey of the GLA Conservative Group has recently released a paper proposing to switch off traffic signals in London at night in order to save London's motorists £40m.

Tracey, the GLA Conservatives spokesman for transport, states;

“Every year Londoners waste over 170 million hours sitting in traffic, costing London’s economy £4bn. Many of these journeys in our city are unavoidable. But rather than hurting motorists with ridiculous charges and taxes, we should look at innovative ways to cut congestion and make traffic flow more smoothly. 

Turning off traffic lights at night, like they do in parts of Europe and North America, is one measure which would boost the economy and help the environment. A common sense approach in the right places would cut idling and therefore vehicle emissions, motorists would save cash as less fuel is wasted, and journey times would be slashed meaning deliveries are completed quicker and cabbies are able to take on more jobs. Even if lights were turned off for just six hours overnight, accounting for non-suitable junctions, drivers could save £40m over four years in saved time and fuel alone.”

Obviously, my "common sense" and "smoothing traffic" klaxons went off together and I thought it might be interesting to explore the paper and offer some other views. Let's start with the statement above. 170 million hours wasted in traffic sounds like a huge number (and I will come to the source shortly), but if London has about 8 million residents then this means that each person spends (on average) 21.25 hours a year stuck in traffic. Or 3.5 minutes a day. Doesn't seem that bad to me.

The source of this data is a 2006 report which is based on data from 2003 which in my book might make for some interesting historical reading, but is so out of date as to be irrelevant. The 170 million hours is derived from the report's suggestion that there is an annual delay of 10,250 million minutes (Table 2) and this figure is arrived at through some complex calculations;


But, hang on, the people for whom Tracey is so concerned are sitting in traffic for 170 million hours between 7am and 7pm, so what on earth has this got to do with switching off traffic signals at night? I can answer that, it has nothing to do with it. This is pure, populist politics. The data is not derived based on people sitting at traffic signals (although this might be one of many reasons for congestion - more on that in a bit). But, let's stick with it.

The paper suggests that this is costing London's economy some £4 billion a year, although the 2006 report suggests £1.6 billion (paragraph 5.2). Sadly, Tracey's reference isn't hyperlinked and doesn't show up in searches. There is reference to the £4 billion in the Roads Task Force Technical Note 11, which seems to have come from the same source which was for 2008/09, published in 2010. Certainly, the 2006 report uses the Department for Transport's COBA Manual (Table 1/1) figure of 930 pence per hour for the "average" vehicle (an average for drivers, passengers, buses, commuting, non commuting etc). I assume that there will be annual uplifts for the figures to get us to the £4 billion (which is quoted at £17 per hour). Of course, these "costs" do not factor in those accrued by pedestrians trying to cross busy roads or any costs to those riding bikes being delayed.

The RTF Technical Note 11 references the US Federal Highway Administration (FHWA) factors for congestion and network reliability (with a bit of London spin!):

Category 1 – Traffic-Influencing Events

1. Traffic Incidents – disruption to the normal flow of traffic usually by physical impedance.

2. Road Works – activities that result in temporary physical changes in road capacity.

3. Weather – certain conditions can lead to changes in driver behaviour that affect traffic flow.

Category 2 – Traffic Demand

4. Fluctuations in Normal Traffic – Day-to-day variability in demand leads to some days with higher traffic volumes than others. If the capacity of the network is fixed this can lead to variable travel times without any Category 1 events occurring.

5. Special Events – Are a special case of demand fluctuations where traffic flow in the vicinity of the event will be radically different from “typical” patterns.

Category 3 – Physical Highway Features

6. Traffic Control Devices – Intermittent disruption of traffic flow by control devices such as poorly timed signals can contribute to congestion and travel time variability.

7. Physical Bottlenecks (“Capacity”) - the maximum amount of traffic capable of being handled by a given highway section. Typical bottlenecks in London are caused by fixed bridge and tunnel capacity. Other factors that impact traffic capacity include bus lanes and cycle lanes.


For interest, I reproduce the FWHA's suggested causes of congestion (which is in the US of course). It is interesting as it shows that the causes of congestion are many and the FWHA's report admits that the matter is complicated and congestion can vary at location and day.

The London spin of course cannot resist mentioning bus lanes and cycle lanes as an impact on traffic capacity which of course completely disregards the efficient movement of people - a bus lane only "takes" capacity for other drivers when it is built, but it must be offset by passengers who have a more efficient journey. Cycle lanes would only take capacity if from existing traffic lanes when a new facility is built which cannot be used by motorists (i.e. mandatory lanes or cycle tracks). 

The three categories are related, but if we strip out unplanned things like weather, planned capacity reductions such as roadworks and special events, we are left with demand and capacity. Where demand exceeds capacity, we get congestion and journey reliability gets worse. Perhaps if Tracey had explored some of these issues, the paper might have come across as being a little more authoritative.


The RTF Technical Note 11 also gives an interesting little bit of information which was some modelling done on Victoria Embankment in preparation for the Olympic Route Network signal timing review. Essentially, the modelling looked at the relationship (if any) between the degree of saturation (DoS - there is more detail in that link) and journey time reliability. It showed that with a DoS above 80%, journey time reliability decreases.



If 100% is the theoretical capacity, then running at 80% will mean the flow is smooth (laminar to extend a water flowing through a pipe analogy). At 100%, there is "friction" (people pulling into and out of side roads, people braking and people behind them following suit, people crossing the road when invited etc). The DoS for a road link will vary because of the impacts on it, but the point is that 100% is not the most efficient flow. Of course, there has been a reducing traffic trend in London for a while now (although current road building policies seem determined to reverse this) and so if this continues, then congestion would reduce and hence the economic cost for those driving during the daytime which Tracey uses as a prop for the argument of people being stuck in traffic because of traffic signals in use at night.

The third reference in the paper is from 2010 where it is stated that London has 6,000 sets of traffic signals (up from about 4,800 in the year 2000). It is no secret that the Mayor of London is pro-car and has had a policy of "smoothing traffic flow" which includes removing traffic signals. In his 2008 paper "Way To Go!" the Mayor stated:

"It is incredible that we have successfully deterred tens of thousands of vehicles from entering the Congestion Charge zone, and yet congestion – and frustration – have continued to rise.

We are now in the process of reviewing all of London’s 6,000 traffic lights, and already we have shaved seconds off red on about 150 of them. A couple of extra seconds on green can cumulatively make a huge difference to traffic flow, and where it is possible to make a difference without prejudicing the rights of pedestrians, we will do so.

We are reviewing 1,000 lights per year, and in many cases we will be asking what the lights are doing there in the first place. Why were they put there? What risk were they addressing? Can we address that in any other way, without bringing traffic to a standstill?"


So, let's be honest, Tracey is just repeating the company line. Don't get me wrong, there is nothing intrinsically wrong with reviewing traffic signals and as well as timing reviews (because traffic patterns can change on a local or network level over time) there may be justification for removals (for example a bypass might render a set of signals in the bypassed area redundant). 

According to the guys at work who have been around a while, before TfL came into existence, traffic signals in London were run by the TCSU (Traffic Control Systems Unit) and it was the case that new signals were funded by the TCSU (the "civils" works were paid for by the borough promoting the scheme). At least in my area, I know of stand alone pelican crossings which were put in because it was cheaper to do so than zebra crossings as someone else funded the signals kit (at least at the point of use - the costs were paid through precepts). TfL now expects that boroughs fund new signals as part of their schemes and with budgets being the way they are, people tend to use them more sparingly these days (and of course there are annual maintenance charges). But, I digress (as usual).

Why do we use traffic signals? According to Tracey's paper;

"There are three reasons why traffic lights are used. The first of these is safety. There are some junctions where traffic signals play an important role in reducing the chance of accidents or injuries.

The second is amenity. Traffic signals can be useful in providing a safe route to a school or reducing the effect of a major road segregating a community. 


The third reason – and the one that has been the key driver in the growth of traffic lights over the last decade – is to help implement wider transport policies, such as bus and cycle priority."

Safety is a loaded point. There are layouts which could be redesigned so that traffic signals could be removed and with any given set of signals (junction or crossings) statistically, there will be collisions occurring as a consequence of how people behave with them. For example, people jump red signals when other people have priority or people stop when they should and get shunted for their trouble. If someone walking or riding a bike is involved, the outcome can be serious or fatal. In 2012, nearly 5000 people were hurt in collisions at traffic signal-controlled junctions (Table 5.2). Statistically, a signalised crossing could attract a higher rate of collisions than it did pre-signalisation.

Compared with situations where there are no signals, it can be difficult for people to get out of side roads or cross roads and so signals help and so there may be suppressed demand anyway - the introduction of signals therefore allow people to move through junctions or across roads where it might have been difficult or dangerous to do so without and this in part could lead to an increase in collisions. Signals are a tool which can enable people, especially those walking and cycling and particularly the elderly and the young. It kind of links to the second point, but this is of course far from "amenity" (what a curious word to use) for many people signals are vital.

The third reason is absolutely fair and what it tells me at least, is that in order to provide for cycling (and indeed walking), we are going to need to use an awful lot more traffic signals to make things feel safe for people on many roads (using or crossing) and this links back to the first point anyway. Of course, this cannot possibly square with the Mayor's policy for removing traffic signals - but they are a vital traffic management tool and so we should be prepared to pay for them to be used.

The paper also quotes a Greater London Authority paper - "Economic Impact of Traffic Signals" to justify turning signals off at night. The paper uses modelling of 5 London junctions to compare a "do minimum" (essentially tweak the signals for efficiency) and remove the signal control. There was a big assumption;

"In modelling traffic movements some assumptions are needed as to how traffic will react without signals. When the traffic signals are removed traffic is assumed to give-way to the right as normal on roundabouts, to give-way to traffic on  the right on 4-arm junctions and to revert to major-minor road status for 3-arm junctions."

It would be interesting to see how a 4-arm junction would be laid out with signals turned off as the modelling assumes that people would give way to the right which is not a UK convention in the event of a traffic signal failure. For a 3-arm junction, reverting to major/ minor would mean that people entering/ exiting the minor arm may well be disadvantaged. As for signals on roundabouts, aside from the ability to incorporate stages for walking and cycling, signal control is often used at intersections of big roads to stop them locking each other up - I am thinking of places such as Bow, Redbridge and Hanger Lane.

In terms of impacts on pedestrians, the GLA report does not cover benefits and disbenefits and for road safety, the commentary suggests that where traffic signals fail this could equate to around 9 PIAs per year (personal injury accidents) compared to 2.4 PIAs per year normally. Failed signals is not a proxy for turning them off, but interesting background nonetheless.

When we finally get to the proposal to switch off traffic signals at night (where congestion is least and journey reliability highest), the GLA report considered modelling of the study junctions at various times of the day and this included an "off peak" between 22:00 and 01:00. The study looked at the economics of removing the signals, but stresses that this is for the study junctions rather than something applicable to the whole of London - each case on its merits then, which is what good engineering advice is about. There is a slight economic benefit in all 5 cases for no signals during the off peak (22:00 to 01:00) period which I have to assume is the thrust of Tracey's point.

You should read the full conclusions of the GLA report, but like any good research, more work is needed;

"In the UK legislation does not allow for the use of switching all signals at a junction to flashing amber at less busy times, a measure which is commonplace in a number of European countries. We recommend discussions should take place with the appropriate European traffic authorities to obtain evidence and ascertain their views on the impact that such traffic control methods have on safety, vehicle and pedestrian movement."

Of course, other European countries also have vehicles turning right on red (giving way to pedestrians and bikes going ahead), arrow-based red signals (for lane control) and where flashing amber signals are used, pedestrians can have priority as the crossings revert to zebra crossing equivalents (please correct me or add in the comments as I don't know enough about international set-ups). I have to conclude that even if a flashing amber was used (in lieu of a complete switch-off) then we need to change our regulations and given that the Department for Transport is killing off the Pelican crossing in the proposed changes to the Traffic Signs Regulations & General Directions, we will have no flashing amber signals at all!

In the economic part of the paper, Tracey argues that £10m per year could be saved across London by turning traffic signals off at night (i.e. £40m over 4 years). The saving is accrued by drivers of course and does not add in disbenefits to pedestrians. TfL is currently rolling out SCOOT which allows junctions to adapt (within parameters) to changing traffic patterns. At night, this translates to more efficient detection and cycle times and probably renders switching off signals as irrelevant now. Of course, Tracey's calculation makes no assessment as to what the costs in terms of new collisions could be - I would lay odds that would more than £10m a year.

If I put human cost to one side, the current economic costs of collisions are as follows;



Essentially, if a programme of turning signals off at night went ahead and there were 5 fatal collisions (I prefer that term rather than "accidents"), then that wipes out the "savings" made by drivers - seriously, is it worth even trying this on pure economic grounds. I don't think so. Is it worth doing to save a few people a few seconds on their night time journeys even if others get hurt or killed? Of course it's not.

Fancy coming back at night for a bit of cross-traffic chicken?
On the TfL trunk road network, the main roads are often set with 40mph and 50mph speed limits and the traffic signals rest on green on these routes anyway. Side road traffic triggers a demand and the high-speed arms get a red to allow side road traffic to access or cross. Certainly, when there is a traffic signal failure on these junctions, TfL's normal protocol is to close any right turns off the trunk roads and to prevent traffic crossing the trunk roads (in essence you can turn left on or off the trunk road). I find it hard to imagine TfL being happy turning signals off at night on high speed roads.

What about in Central London? Lots of areas are busy well into the night with traffic, bikes and pedestrians (I am thinking the West End for example) and so I cannot see those junctions being suitable for switching off. Where does Tracey suggest we turn signals off? Well, he gives some recommendations;

1. Where it is deemed safe, TfL and London’s Boroughs should turn off London’s traffic lights between midnight and 6am.

2. TfL should, as a pilot, turn off traffic lights at 100 junctions during daytime off-peak hours. London’s Boroughs should look for opportunities to do the same.

3. TfL should perform regular wide scale reassessments of their current traffic lights to see if any are redundant under their current standards.

In response to the first point, I have given a couple of types of location where it wouldn't be safe to switch off signals at night. I have also thought about my own area and I would not wish to put my name to any report or decision to switch signals off - good luck with that one.

On the second point. Oh, hang on, the paper was about switching off signals at night and now Tracey fancies some during the day too - how on earth are people going to be able to cross the road under those conditions? Yes, nothing wrong with the third point as things change over time and actually signals may no longer be needed and other things could be looked at (such as roundabouts with zebra crossings on all arms).

At the end of the day, Tracey has (like me of course) picked on snippets of information and used them to justify a political position which is chiefly to turn off traffic signals at night. He has mixed up various studies and papers to get the result he desires and as far as I am concerned, I simply do not think it holds up to scrutiny and I am sure the modelling experts and academics can pick a few more holes in the ideas too. To be fair to Tracey, a politician's job is to question the status quo and to ask searching questions about accepted wisdom or even why is something done a certain way - yes, we should review how traffic (in the widest sense to include all highway users) operates in our city, but Tracey comes at it from the put down motorist's point of view;

"rather than hurting motorists with ridiculous charges and taxes, we should look at innovative ways to cut congestion and make traffic flow more smoothly."

That is where I take issue on all of this. Tracey's congestion is that experienced by the private motorist. His traffic is the private motorist. Congestion (and indeed journey reliability) is complex and the solutions can be complex, but it always comes down to the point where demand exceeds capacity. The ideas in the paper are tweaks to improve night-time capacity, but this is when congestion is not an issue anyway and so makes this a political dogma - similar to that of people wanting to drive faster on motorways at night, or ignore 20mph limits outside of school times.

All in all, the paper is an extension of the Mayor's car-centric side and is in direct opposition to making London a more walkable and bikeable (indeed liveable) place. The position also has to be anti-bus, as technology is used to give buses priority through junctions. It also hints of a disregard for road safety in the widest sense - all to save £10m a year in a city of 8m people. If only there were other ways of moving lots of people around efficiently.