Saturday, 21 November 2015

BRS: Lessons from PDX

The Bristol Traffic team has actually been on a council-funded trip round the world to see what ideas we could adopt in the city to make it more successful. Finally, after months of first class travel and hotels, we have found it -in Portland Airport.

Portland is a relatively small city in the US; less population than, say, Glasgow —and doesn't actually merit an acronym or nickname the way, say 'NYC, LA, Vegas" and others do. Instead it tends to adopt the initials of its airport, PDX. Bristol is similar, except most people in the UK don't know the initials for Bristol International Airport, BRS. Well, use it enough and maybe they'll learn.

Anyway, the first thing you see thing when you get off your plane in PDX is the signs towards some bicycle assembly area. THIS IS NOT WHAT WE ARE ADVOCATING.

A bike assembly area in BRS would only go in if the airport could charge cyclists for using it —and they could only do that by making it illegal to assemble your bicycle near the airport. They'd probably just make it illegal to cycle to it, just as LHR have done by converting the cycle tunnel to road traffic and fining anyone who cycles down it.

No, what's of interest to us is the sign 180 degrees behind the camera here, the one at airport security

Please be advised recreational marijuana is not permitted on flights travelling outside of Oregon.
That's a bit late to see that sign; there isn't one when you load a 14 kg rucksack in as hold luggage, and it is clearly one with implications. If they have to have a sign saying "you can't fly outside of Oregon with weed", then by implication "if you are flying within the state —you can". And they are right.

It is now legal to grow 4 ganja plants of your own: provided you live more than 1000 yards from a school. Imagine that —people would be looking at the catchment area maps of the city to make sure they weren't living near a school; it would turn the current game on its head. House prices would actually go down the closer you were to a school.

It even complicates the university: should their agriculture department start projects to advise farmers on the growing of industrial scale marijuana? Some proposals are on hold because it conflicts with federal funding, and despite the enthusiasm of graduate students to study for a PhD in Marijuana Agriculture, the existing farmers have many years of experience growing weed. All that is happening now is the farmers can do it in public and pay income tax.

Because that's where things are going: industrial scale farming for selling in California and Seattle. It's now got a new problem for the city: how to manage the planning permissions for where to grow and process this "new" commercial product.

It's actually been an open secret in the state that weed was the big rural earner with the demise of logging; it battled with Intel x86 parts for maximum income and profit margins —it just wasn't something that could be discussed publicly. And, unlike CPU foundries, it's something that those towns whose livelihoods had been destroyed by the end of logging could take up, more reliable income than tourism, and generally a wholesome product people could enjoy,

Imagine if Bristol legalised the recreational use of ganja, the growing of plants, and in N. Somerset, full scale agriculture.

It would transform the city!

We would become the powerhouse of the south west, one to rival London! We'd get visitors from all over the country to spend a weekend —and Weston super Mare would become Britain's most popular summer holiday destination.

It would also finally end the gulf between the city and the countryside. The North Somerset Agricultural Show would be transformed from somewhere where range rover owners from near the A370 could turn up and talk about their "crops" to one where range rover owners from near Montpelier could turn up and talk about their "crops" —and the Somerset farmers would listen intently, offer to buy some of the product, then even offer the city folk some paid consultancy.

As the ganja industry grew, North Somerset would move beyond a dormitory county for the city, to one where people would commute too from the inner city, to help "work the farms". Oh, and then there's the pick-your-own harvesting event, which would be a national festival.

And of course all this will bring in money: the tax from the plants, the income tax from the staff, staff who will be earning more than minimum wage as they bring the skills acquired over the years to full use. All those visitors, those tourist events -more money, enough for Weston to move beyond Dismaland as a national tourism event. And all the town will be outside on a sunny summer evening, lighting up in the parks, turning up the sounds of Bristol music, and getting stoned of our heads.

How about it then, prospective candidates for Bristol Mayor? Who is going to look at the lessons from Portland, Colorado, Seattle —and campaign on a "legalised marijuana industry for the greater bristol area"?

Wednesday, 4 November 2015

The new Mass Surveillance State bill

Taking a break from traffic issues, we should note that Bristol Traffic team  has long admitted to building a mass surveillance police state in conjunction with google and facebook —our Datacentre State.

In fact the main difference between us and GCHQ is ours is run from an Ubuntu laptop in the comfy sofa bit of the Canteen. That's just down the road from this painting, behind the riot police in the distance

Now that the new Mass Surveillance State bill is up, we should do a post on how we would implement it and cost it out accordingly. Some request logging  -> Apache Kafka -> Hadoop HDFS pipeline with hourly scheduled MapReduce or Spark jobs compressing the time-series logs a compact and fast-to-scan format like Parquet or Orc. This could then be queried direct via Facebook's Hive, or imported into NSA's open sourced Accumulo column table DB for even faster lookup. Each ISP/mobile telco may host their own "facility", but sticking them all in the same datacentre would ease low-latency cross-ISP queries issued from government computers, while still pretending they were "separate"

In the meantime, let's pick on some talking points that are being used on the radio and TV to justify the bill and make it look like the government listened to feedback

The nature of technology has changed and we must adapt.

People have been browsing the web for 20 years, even skype is about twelve years old. What has changed is the cost of storage. Back in 2008 we were quoting a few hundred dollars for aterabyte. seven years later and the cost is $30/TB and density shrunk to the extent you can get a couple of petabytes in two wardrobe-sized server racks. That's the big change: governments can afford to store all your personal data.

The pages you visit won't be recorded, only the sites.

With the migration of the main web sites to HTTPS, the ISPs couldn't log the pages anyway. There's no concession here: if your browser shows a little green lock in the URL line, the government couldn't record the page. What they can do now is go to facebook and say "Someone at went to at 21:14 on Tuesday: what did they do?" Facebook, will have the rest of the information for them.

This is just like an itemised phone bill.

No. It's like a log of every game you played on your PS3, every program you watched on BBC iPlayer, every photo you took which your smart phone backed up (and where). If you read books on an Amazon kindle —or with the app— its a log of whenever you turned a page or turned back. Spent too much time reading "extremist" bits of the Koran between bouts of Call of Duty and facebook posts? That'll be something they'll be able to work out by looking at the URLs and then asking the service providers for the details. Here Sony may come out the best —unless they start recording chat sessions. Amazon? They'll probably record the ambient light and tablet rotation while you were reading those chapter of the Koran.

We won't ban encryption

They'd only be laughed at if they asked for this. The algorithms (RSA, Elliptic Curve Cryptography) are well known. You can't stop RSA working without banning prime numbers. ECC is potentially even harder. though the fact that NSA are no longer recommending is use implies they don't trust it any more. Either they've found some new math or built some new hardware ... so longer key RSA is back in fashion. All the homeoffice can do is go to FB, google, Whatsapp and say "please store the communications so we can ask for it", then drive round to Apple and say "add a back door to iPhone encryption —we promise we won't abuse it, lose the secret key or otherwise destroy its value.

There is some mention of "informal arrangements" perhaps the government has had meetings with all these people, and said, "give us access and we won't review your tax status". But that isn't going to work with those companies that don't have a UK outpost who can hang up the phone when Theresa rings them. Note especially that some of the best cryptography libraries, Bouncy Castle are explicitly developed in Australia to avoid US regulations on RSA key lengths. And guess what's been ported to Android? Building an Android device-device app with unbreakable encryption is straightforward enough to make it a final year project for a Computer Science course at any of our local universities —how could that be criminalised?

We're only formalising what's been going on.

Ignoring the fact that this implies that previous governments have clearly been granting warrants to log the actions of every citizen, the fact that they've been doing this is a key part of the UK-side of the Snowden leaks. In the US this has led to a rethink of state/citizen rights. Here its leading to the government not only formalising the existing state of affairs, but expanding it.

We won't monitor MPs communications
Bulk data collection renders this impossible. How you know that the person posting to twitter from an internet cafe is an MP or a possible enemy of the state? You can't, you just grab it all.


The core concessions aren't concessions, they are the result of the engineering teams of the government and the ISPs telling them what doesn't work, and the politicians coming up with ways to frame this in terms of concessions, rather than acceptance of engineering and cross-border realities. They've also hidden the key implication: they can now afford to record every single interaction you make with a remote computer, and, with informal and formal arrangements with the providers of those services, get the details.

Meanwhile, your civil liberties have been suspended for the duration of the emergency.

Saturday, 24 October 2015

Governments have the most interesting data. Today: MOTs

There's a new web site., which lets you type in any registration and make of a car and get its entire MOT history. Excluding cars < 3 years old, this means you can get the effective history of a vehicle.

This is fascinating, especially when you use it to look up the history of a vehicle you've sold on (*).

What is equally fascinating, is what is shows about things you can get away with. In particular, holding wing mirrors on with masking tape is not an MoT failure.

You can also get away with: tyres nearly worn down, steering in trouble (wheel balance?), suspension in trouble, exhaust corroded, small damage to your windscreen.

You actually have to wait a year, get those front tyres below the 1.6mm limit as it rubs slightly against the wing of the car before they say "no, time to fix the toy"

By May 2015, this car (WP53JVM, for curious), fails because bolts are missing on the wheels.

Now, you can argue about wing mirrors, suspension, etc. But driving around with bolts missing from your wheels? That's not just cause for keeping the car in the garage, that should be cause for arresting the driver for some offence related to driving in a way to endanger everyone nearby.

Anyway, it's interesting data, and you can get it for any car.

Which means you can now do some interesting data-science projects —including some which would be something schoolkids to do as "maths in the real world" projects.
  1. Look at all your friends' and neigbours' car histories and see whose is the one most likely to cause a crash. Then make a note of who never to accept a lift from, especially at night, in the rain or winter conditions.
  2. Do a census of the entire history of all cars in your road over 3 years old, counting the pass/fail ratio as well as numbers of advisory issues. Then repeat this for other parts of the city, to determine the different vehicle quality statuses of the region.
  3. We've always asserted that cars in montpelier only need wing-mirrors for the MoT. Does the data imply this?
  4. Use the historical mileage data of cars over four years old and use this to determine the average annual mileage of cars in the same streets. Is the MOT failure rate proportional to the miles across all parts of the city, or are some cars continually failing even with short mileage? Those are potentially the vehicles driven more around the city.
  5. Using that historical data, have the miles driven by residents increased or decreased after the RPZs were rolled out? What about people who don't live in an RPZ yet have jobs in the city centre or nearby?
  6. When buying a car, look up its history. It is a sign of a car that is maintained, or one neglected?
  7. Look at some lorries. Is their failure rate better or worse than other vehicles? What about vans?
The scariest thing to consider is this: the MOT certifies that a vehicle was considered safe by MOT standards for one single day. The car above could have been driving around with broken windscreen wipers, failing suspension and missing wheel bolts for 364 days before it failed its test. After being fixed, it now has another 364 days for its brake pads to finally wear too thin, tyres to wear out, those coil springs to finally corrode through.

Drivers like these are potentially some of those who complain about cyclists "not having MOTs on their bicycles". Well, with drivers like that, who cares about the state of the cyclists' bikes, other than whether or not both their brakes work? Because they aren't what you have to worry about, whether walking, cycling or driving. It's the people driving round the city in a VW golf with underbolted wheels, worn brake pads, failing suspension and defective windscreen and wipers.

To close, then: a competition for the weekend. Pick a car you see ~ 10 years old, put in its history and find out exactly what it's been failing MOTs for. We want the most dramatic reasons -and so far "missing wheel bolts on two wheels" is it.

(*) Actually it wasn't that vehicle, which was WP53JVO. Getting the last digit wrong turned up what must been another of the last batch of MkIV Golfs to leave the VW dealer.

Wednesday, 21 October 2015

Bristol's 2015 Bike Survey. If its so wonderful, why do twats swear at you for cycling?

Sustrans have just published a 2015 survey on use and opinions on cycling in Bristol. This is available as a PDF for anyone who still prints things, and, on Page 2, comes with a sepia tinted photo of Our Glorious Leader for anyone who hasn't seen him recently.

Lots of people will be praising this, so we'll be ruthless and go the other way.

First issue: where do the numbers come from?

There is a full PDF of the methodology, which is what all surveys need: Something to back up the dataset. This shows that the Bristol survey was a phone survey of 1100 people, selected by random dialling, and quotas to match demographics in the area, then some 300 booster surveys to find cyclists who have real opinions on the cycling facilities.

One of our team members got a survey call, so we know two facts about it
  1. It was made to a landline. It therefore implicitly excludes all households without landlines. Ofcom's figures would imply that excludes 15% of the UK population from the survey; there's no data for Bristol itself.
  2. It was conducted mid-afternoon on a weekend. This may lead to selection bias towards boring people who don't have lives, parents stuck at home with children included.
What we don't know is how wide the survey went. Did it cover the bits of S Gloucs that is the part of Bristol full of people who hate speed limits and residents parking? Or did it only cover BRS and Avonmouth?

Second issue: why be so positive in the interpretation

Here's the negative view of Page 5
  1. 28% of people don't "like to see people out and about on bikes". Cyclists: these are the people shouting at you.
  2. 32% do not believe things would be better if people in general rode bikes more.
  3. 26% do not believe that more people riding bikes would make Bristol a better place to live and work.
  4. 46% do not believe that things would be better if friends and family road bikes more.
  5. 52% do not feel that they should ride a bike more.
  6. and from p10: 30% of residents would not like to see more investment in cycling in Bristol.
This may be excessively negative, as the PDF doesn't differentiate "no" from "don't know". All we know is that it is not positive. But lets go for the worst case here.

Over a quarter of the sample set in the survey don't like to see people cycling. More than half don't feel that they should ride a bike more. And, nearly half (46%) don't even want to see friends and family riding bikes more. Maybe because that would create an inconsistent view of cyclists as outgroup vs friends-and-family. We don't know —the data isn't there.

What we see then, is a divided city.

Now, what other bits of the survey are interesting?

P10: bike routes

Notice the popularity of traffic free cycle routes and protected bike lanes amongst all current and potential users.

Notice the complete disdain for shared pavements amongst non-cyclists and experienced cyclists alike. The fact that even the "don't ride a bike but want to" group don't like shared pavements shows how the two-track route policy in the UK, "magic paint on the roads and shared cycle pavements" doesn't even deliver for the people who would like to cycle. Time to knife the baby there.

Similarly: nobody likes bus lanes except for experienced/regular cyclists. Even there, ask them "do you like to be stuck behind a first bus in full early morning black smoke mode" or "do you like to have a bus right behind you?". These are details we'd like to know.

P11: demographics

Older people are under-represented. The pie chart doesn't actually show the number of respondents who cycle vs. the demographics of the city as a whole, so it' not that useful. Let's assume that yes, there are less elderly people. Look at the pie chart next to it. ~50% commute, some (2%?) to school and then 4% to college or university. We're going to take a guess here, but you won't see many of the 55+ going to school or college, or in the 65+ range commuting. You'd expect to see a reduction. More interesting, the smaller 45-54 range (14%) vs. 35-44 (23%). 

The 16% of of people riding bikes who identify themselves as black or minority ethnic —the same as for the city. This is interesting, as it implies the claim that cyclists are all white middle class men is not true in Bristol. But we still see 69% of cyclists identifying as male vs 31% female, showing significant gender disparities in a city where the percentage of sexes is approximately equal. And there is no income related data to look on that axis.

Between 2013 and 2014 the number of trips made by bike increased by 4%

What does that mean? That the percentage of all trips made in the city increased by 4% in one year? Or that in 2014 the number of bike journeys was 1.04 times that of 2013? And if so, how does that compare with the percentage increase in: car journeys, walking, train and bus? More? the same? Less? We need more context for that sentence to parse it correctly.

P13: Metrobus

"with the Metrobus giving hard-pressed commuters even more travel choice, our roads will become even less congested, and better for people on bikes and walking." Someone paid sustrans to write that. Because it should be "with the Metrobus making cycling harder in the city, our roads will stay a congested mess, and while it is being built the centre cycle-crossings and Create centre bridge have gone"


There is nobody in any of the 30-40 photos looking wet. This is an unrepresentative sample of Bristol days. We'd have expected waterproofs to be visible and needed in at least 25-30% of them.

p8: routes

There's 116 miles of "bike route", "79 miles traffic free", and "1 mile of protected bike lane". 27% of people live within 125 metres of a cycle lane, track or shared use path. Well the survey showed that everyone thinks shared use paths are worthless, and "bike route' is vaguely defined here. Presumably it includes anything painted on tarmac, which is effectively meaningless.

Page 12 follows this up with some assertions that 1/3 of morning rush hour traffic is bicycles, and that Gloucester Road has comparable numbers to the railway path. Here is Gloucester Road outbound at 16:30 on this very weekday. As such, it's not something we've been saving for a special occasion, simply a normal weekday, with here the passenger of WU56JKV swearing at the cyclist as they go past.

The driver appears to be concerned that the cyclist "was in the middle of the road" while cycling past the parked cars and the road junction where the traffic island means that the middle of the road is the place to be. They were clearly concerned enough to shout "get to the fucking side". The fact that they'd wound up the window when next passed shows that they hadn't expected to be passed again, as they had to go to the effort of winding it down to make more hand gestures later.

As for the reason for the abuse, "middle of road" was it, though they seemed unable to proceed even after the cyclist had expressed their apologies and invited them to go ahead. It's almost as if they were, to use a phrase, four fuckwits without a fuck or a wit between them.

  1. You can't see it in the photo, but the front tyre was pretty much smooth on the outer 1/4 of the tyre. Tapping the reg# and make (ford) into the MOT history site shows the MoT is due soon, and they have a history of bald tyres. We'll check back in a month to see if that tyre earned a failure. If not: they've had to suspend it.
  2. At 0:33 you can see that one of its brake lights is dead. This is a defective vehicle.
  3. Given that they stay in the same position from 0:33 to 1:33, a minute at a red light, perhaps it is their frustration at having to wait so long which is leading to their anger management issues.
  4. Note how everyone in the vehicle hates the cyclists being there. These are all from the 28% of people that don't like to see people out and about on bikes.
  5. As this is after 16:30, anyone parked in the bus lane is illegally parked and can earn tickets; its generally the buses that suffer the most from parked cars, but you can see a few times where the cyclists have to swing out.
  6. The GPS route map may be accurate, but the speedo is clearly confused, has some bad weighted-moving-average parameters, or at least one of the GPS satellites has just fallen out the sky while still broadcasting its position.
  7. The actual Strava numbers for this segment time that cyclist as 19.7 mph, top 100 of the 3500 riders logged, fastest of October to date. In a 20 mph zone, this is not someone you have to wait for.
  8. That intermittent bit of paint on the side of the road is probably 2 miles out of the 79 miles of bike route, and definitely part of the kind of cycle lane which 27% of people live with 125 metres of.
The last is interesting, as it says "is that all you can do?", "how does this stop cyclists being sworn at", and "what would the numbers be if the 75 cm path didn't keep disappearing under buses and vans at corners?"

Regarding the passenger of the car, we're going to try a new experiment today. Report them to the ASPoliceWest and ask for a caution for abusive behaviour or a section 59 ASBO. The ASBO strategy is to see what excuse they will make up for not issuing one, as they can't cite court costs, leaving only "we don't think swearing at cyclists is antisocial". Let's see, shall we?


We're seeing a polarised city here, one shown in both the survey results and today's field test of a ride up Gloucester Road, —a road the survey calls out as a success, but which we document as "par for the course".

It'd be interesting to know the postcode split of the like to see bicycles/hate to cycles answers, and their demographics. While there appears to be an ascendant movement to cycling in the city, the anti- forces are a significant number and do form a noisy minority — not just swearing away at passing cyclists.

Saturday, 17 October 2015

Autonomous vehicles: Google are the new British Leyland

After spending a month with our strategic partners in a privatised-PCSO state, you soon get fairly used to the sight of Google autonomous cars. There's two types, the original Lexus models, and the smaller kitty cars. The latter are clearly designed to avoid scaring people witless that machines are taking over the freeway. It's as if in Terminator, the T1000 had been dressed up as a telly-tubby after being beamed back in time. Sarah Connor and compatriots would have been so busy saying "Oh, isn't it cute" to notice they were being shot to pieces by Skynet.

Maybe google should buy a kitty car and paint it up like Schwarzenegger in the final stages of Terminator & see whether it gets cut up less: an interesting little field trial.

So what's like to drive round town when there are these things on the route?

Here is one spotted during a morning commute on El Camino, the road where bus lanes are being opposed as autonomous cars will solve all problems.

It is legal to use a phone while stationary, so this photo was legal. However, the photographer is clearly not paying attention. Nor are the two googlers in the lexus, as they chat to each other -but they don't need to.

Which promises a wonderful future, were it not for the fact that Google's entire computer infrastructure is built on the decision that rather than spend lots of money for hardware that doesn't fail,  just buy cheap boxes and let the software deal with the failure rate. For example, whereas even your home network store can be "RAID-5" for redundant data storage, Google's filesystem, GFS, just stores three copies of your photos and re-replicates a copy if one of them goes way or gets corrupted. That is: google accept things to fail and hide it from the user. Similarly, anyone who has ever owned a Google Nexus phone will know that they're as unreliable as a mid-1980s Mini Metro. A couple of months ago, Google shipped an update where the flash and the photo taking were out of sync. The flash went off, then the photo was taken after the flash had gone. What kind of QA process lets that out of the door? Unless they used the Volkswagen strategy, "detect when you are testing the phone and have the camera work", or their test image was a black object against a black background, detecting flash/snap synchronisation failures during the test process should be trivial. Which implies google did near-zero testing, but instead pushed the patch out over the wire -to their own Google Nexus phones- and then waited for complaints to come in.

Can you trust these people to build cars? Cars which are all required to reach their destination with their payload alive, rather than ones where its OK to have 99.3 percent arriving, and a paper "Failure trends in large self-driving car populations" of esoteric interest to those who work in computer hardware? Cars when you want things co-ordinated like the camera and the brake pedal, so it it sees a lorry coming it will stop in time, rather than 15 seconds too late?

It's not just that they're just out of their depth, they've made it a fundamental tenet of their system architecture: things fail, get over it. We'll hide it the server software, while client side we'll just push out an update once we get bug reports coming in.

Which means anyone who owns a google car would be reluctant to accept that update; you'd wait a week to see if The Register was warning of bugs in the steering or braking systems before you hit the "accept" button on a patch, that is, unless you wanted an emergency fix to some problem like "doesn't recognise oncoming HGVs"

Not in our photograph, to the left of our photographer, is someone in a Tesla-S electric car. These are the status toys of the electric world. Not toy cars like the nissan leaf, but performance luxury vehicles where the electric feature is not just to keep costs down on the commute, or to allow you in the car-sharing lanes when on your own, but to show off, "my facebook stock is up and I can afford to be smug".

The driver of the Tesla is not only looking down at their phone, they appear to be falling asleep while they do it. Every so often their head jerks up, not in the "I'd better look to see if the lights have changed" style, but in the "I'm falling asleep but shouldn't" style. Whatever their friends are up to on Facebook, it's not interesting enough to keep them awake on the commute.

So which future do we have to look forward to?

  1. Self driving cars from a company whose view on what reliability constitutes "acceptable" is on a par of what British Leyland thought in 1978.
  2. Non-autonomous electric cars driven by people who can't even stay awake long enough to read messages on the phone.

This is the future —and either way it's pretty bleak.

Saturday, 10 October 2015

The spectator discovers sectarian Bristol

Once every 18 months, the Spectator magazine covers Bristol with an article. This is something we residents we have on our "things to look forward to" list somewhere between "Shopping in Asda Bemmy on a Saturday" and "getting stuck on the M4 because there's a rugby match scheduled to start in Cardiff soon".

This year we are blessed with many opportunities to get stuck on the M4. We are also graced with the latest spectator article, Bristol, the European capital of green nannying and bureaucracy.

Here are the opening three paragraphs:
I am stuck behind a big yellow recycling lorry in Bristol, which this year became the UK’s first European Green Capital. It is collecting food waste from the special brown bins we have to use, and the stench is horrendous. Behind me are about another dozen cars and, sad to say, I fear that not all of them have turned off their idling engines.  
Squadrons of recycling vehicles invade every day, blocking our narrow Victorian streets and causing misery and mayhem — starting with the school run: ‘Dad! I’m going to be marked down for a “late” again!’ ‘Sorry son, but these teabags mustn’t be allowed to rot in landfill. And besides, we have our city’s green status to consider!’ 
I am not against recycling — just the extreme methodology the city has adopted. Bristol is now so over-the-top with it all that bin day involves five or more different bins collected by three separate diesel–powered lorries. And I have a theory about why these mobile compost heaps insist on working through the morning rush hour: it is all about our city’s war on the car.
Mr Miserable then actually goes on to make the point that Bristol has gone from being the city of ganja and Trip-hop to one of painted road regulations, blaming "green city europe" for it. Well, he may have a point. Certainly there is a visible split between those people who were happy with "The way thing were" and the progressives,. The "way things were" brigade are still sulking over the (last) rework of The Centre, the loss of the rickety flyover, and probably even the loss of the road over College Green. Notice how roads are the key source of resentment. Similarly the progressives are full of hope that with an RPZ and 20 mph limit all those people sulking about stolen roundabouts will suddenly choose to cycle happily to work.  Well, the sulkers won't be doing that out of ideological reasons, even if their GP says they need to do it for their emergent Coronary Heart Disease and Type II Diabetes.

Ironically, both groups have lots in common: they all think Bristol being "european green city" is taking the piss, and that Metrobus is a disaster in the making. Nobody anywhere can be found to defend Metrobus except bus companies, and the engineers in WoEP who find designing continuous bike routes too boring to bother with.

Anyway, on a standard of the Spectator's usual coverage, no worse than usual, and it doesn't laugh at us rural folk who live outside the Home Counties.

What is irritating though, is the whole theme of those quoted paragraphs. He has spent a fifth of his article citing being stuck behind a bin van on the school run with the other parents as evidence for the council's "war on the car". That's it: stuck behind a bin van.

Now, nobody likes being stuck behind the rubbish or recycling lorries, but here is a key aspect of them:
they come on the same day every week
Admittedly, whether it's a brown and recycle week or a black-bins-too week is a mystery to all, but that is addressed, as everyone does, by sticking them all out on the street. Any that don't get collected can be left there for the following week. Because, as noted, they will be back exactly seven days later, except around Christmas and New Year -but there, as a gift to the parents, the council allows them to take off three weeks worth of school run, so the schedule is irrelevant.

Because bin day is so regular, you soon learn which days the lorries come out on the rat-runs between your home and school, which means remembering the 1-2 days a week when you have kick your child out of bed a bit earlier and say "we need to go to school now, get up you lazy bastard".

But no, clearly Anthony Whitehead never remembers to do this on the morning after he (hopefully) helped stick the bins out. Which implies its more a war on "lazy and forgetful parents".

Having failed to learn a useful strategy for avoiding being late one day a week "get out of the door 10 minutes early on bin day", he is instead stuck in a line of cars trying to compose his magazine article.

This is where he makes his second fatal mistake. At the moment he realised that he was blocked in, and that he wasn't going to get the child to school in time, instead of foaming off at the council or writing an article for the Spectator, he should have put the handbrake on, turned round to the child and said "get out of the car and walk from here".

Because that is the real split in the city; those who drive their kids to school and those who don't. For a parent driving their child in to suddenly say "get out and walk" is as unthinkable as anyone who works in Clifton using public transport to get there.

Yet still the council tries to force families to walk their kids to school. And it's a war that's been going on for decades

Here is a shocking video showing hordes of children forced to walk to school -even those whose parents are important and own more than one car.

Listen to their happy laughs over the birdsong! Look to how their irresponsible parents let them scoot ahead to the next junction, rather than holding them tightly by the hand on the dangerous journey from the front door to the back seat of their Euro-6 certified crossover SUV. Note the road closures from Ninetree Hill to Freemantle Square, and the later one just before Colston School -and see how they have killed off the traffic-flow-enhancing through traffic. Observe the near-complete lack of traffic apart from a white builder's van, en route to a wage-earning job, one car going up Cotham Brow and a bus.. Note specifically, the presence of RPZ paintwork in the Kingsdown and Cotham North zones are preventing any of the workers Bristol depends on from driving round in circles until they can see a free corner to park on.

All these children are being deprived of the opportunity to snapchat their friends from the back of Crossover SUVs stuck behind bin lorries! All their parents are deprived the opportunity to show off the size and ostentatiousness of their land-barges, hence provide any form of visible wealth to indicate the social status of their offspring! You can't see who is poor and who can afford a car! And long term -these children will grow up as yet unable to grasp the core tenant of Bristol: you need a car to get on.

Sunday, 27 September 2015

"VW cheated —so we need 30 mph!"

Someone called, entertainingly, Pointer2null , comments on one of our 20 mph posts and argues that:

Because VW cheated its customers and governments round the world, we need a 30 mph limit.

It's the pollution, you understand.

He cites two papers, so let's look at them.

An evaluation of the estimated impacts on vehicle emissions of a 20mph speed restriction in central London, City of London Study,  2013:

The opening paragraph says
Average speed models suggest that a lower speed limit in urban areas may result in higher pollutant emissions. However, the stop-start nature of traffic in central London means that such a method may not be suitable, and further investigation is required.
That's the scientific way of saying "its the acceleration from 0 mph that uses fuel, stopping wastes it —so simple models of constant speed are unlikely "may" to apply. Give us some more money and we'll tell you. Actually, the VW debacle has shown that some real-world experimentation would be the strategy. Fit a car with the sensors, drive round an area the month before a 20 mph rollout, then the month after -and see what changed. Back-to-back tests should be relatively accurate, though term-times and weather patterns are factors to consider.

Looking at both the 30 mph and 20 mph modes, they noted that in a 30 mph zone more time was spent accelerating (==higher RPM), while the cruise at 30 mph may more fuel efficient, its not there for very long. with slightly different roads in the study at 20 & 30, you could argue about whether the cruise and acceleration profiles would be the same at 20.

They then go on to conclude
  • It is concluded that it would be incorrect to assume a 20mph speed restriction would be detrimental to ambient local air quality, as the effects on vehicle emissions are mixed 
  •  The short-comings of using average speed models is highlighted, with the specific example of the potential to underestimate emissions of NOX from diesel passenger cars
Pollution metrics were taken off stated manufacturer levels, so, as we know: massively underestimating the pollution of the diesel fleet, while much more accurate for petrol. This means well have to discount one paragraph
Emissions of NOX and CO2 are seen to be higher over 20mph drive cycles for petrol cars and generally lower for diesel cars. PM10 emissions improve for smaller vehicles over 20mph drive cycles (less than 2.0 litre engine size), but are shown to increase for larger vehicles. The order of magnitude is such that future trends in fleet composition will be important.
The authors of the paper would really need to take the real-world figures for petrol and diesel and model the pollution levels based on those numbers, using the acceleration/speed profiles gained in this experiment. Perhaps a future paper is forthcoming.

20mph roads and CO2 emissions, The AA, Undated

This isn't a paper, more a press release. You can see it in the headline, Lower limits can increase fuel consumption and CO2 emissions. Scientists would be more circumspect, and use the word "may" in their work, especially for one single experiment.

The article is about an AA field test measuring fuel consumption in petrol vehicles. Like the CoL paper, it calls out stop-start driving and implicitly the acceleration profile, as the real killer:
  • Change 30 mph zone to 20 mph: increases fuel consumption by 5.85 miles per gallon, or 10.1 per cent.
  • Add speed humps to a 30 mph zone: increases fuel consumption by 27.3 miles per gallon, or 46.9 per cent.
It doesn't look at diesel, and the initial measurements are from the steady state "driving at 30 with no traffic jams". The Millbrook Proving Ground they mention does have a "city track",  hopefully that was the one used. A real paper would provide such information.

What it shows is that speed bumps are the enemy of breathable air. The fact that the Bristol rollout doesn't have them, must therefore be viewed as a good thing.

Comparing the AA press release with the CoL study, it is the CoL one which is scientifically defensible. They discuss the experiment in detail, how they cleaned up the data, the maths to reach the conclusions. And even in the conclusions they state their uncertainties. They are scientists? The AA: an organisation which came to the experiment with an expectation of what the answer would be, ran a field experiment which is unlikely to reflect an inner city, didn't describe that experiment very well —and came to a simple headline conclusion which failed to represent the uncertainties in the findings.

Were that to be be a paper submitted to the Bristol Traffic review team, it would have been rejected due to lack of scientific rigour.

PointerToNull, reads them and comes to the conclusion:
It's all over the news today - the NO2 figures for diesels has been faked. So this make the decision to force all petriol vehicle to observe a speed that INCREASES NO2 emissions by 8% even more short sighted (this is a measured increase by the study and not a claimed one by the makers). Given the state of diesel, petrol will probably be the dominent fuel and so in a single stroke of stupidity, all the gains made by better engine technology in petrol vehicles over the last decade has been wiped out. To press the point, the number of people who will die from air pollution will increase more than those who are saved by slower vehicles.
We're not going to disagree with anything here. They (he? she?) focus on the better of the two papers, and while skipping the "more data needed" bit of the conclusions (academics like that, it's how they get more money), makes the case that speed limits should be driven by what is optimal in terms of pollution profile.

This is a dangerous argument to use. Why? Because to say "we must choose our speed limit by optimal CO2/NOx levels", then you have to be pushing for the motorway limit to be 60 mph. Fuel economy drops significantly after that, and pollution levels increase.

Anyone advocating 30 mph urban for the sake of pollution levels, must also advocate a 60 mph limit, else they are picking data to suit their opinions.  If you did care, you won't drive short distances on cold days, or when pollution levels are already over the limits. 

Then there's also the painful fact that inner bristol's air pollution levels are beyond the legal limits, even before the 20 mph rollout, and includes the M32 corridor.

That is

-Bristol's NOx problem predates the 20 mph zone.
-it seems to correlate with some of the main bus routes: A38 and stapleton road
-it also covers the M32, which had a 60/70 mph limit in 2012.

Leaving the limits at 30 mph would have done nothing to address this problem. And while VW and friends were promising to everyone that all they had to do was wait for the Euro6 rollout, that's not going to cut it either. Which means we'll have to try other things.

The goal of the 20 mph zone is to get more people walking and cycling, not driving their kids to school in turbo-diesel cars. Then if we can get people in the core to not drive on short journeys, potentially increase traffic flow overall.

The future of urban cars is probably hybrid, maybe electric, though the economics and logistics are still dodgy there (expect some post on Tesla vs Google soon —TL;DR you'd have to be driving a lot for a Tesla to make sense; if you buy one you almost want to drive more to reduce that cost/mile). Certainly we don't need to be looking ahead to city centres with diesel, because dieselgate may be the trigger to accelerate restrictions or C-zone charges for them in Bristol, possibly starting with the RPZ.
"the number of people who will die from air pollution will increase more than those who are saved by slower vehicles.
This is potentially -and terrifyingly- true. But the response to NO2 problem should not be 'let's have 30 mph limits in town', because that will not address:

  1. The fact that with the average speed of cars in Bristol being ~16-18 mph at peak hours, even on the M32, the 20 mph limit is irrelevant at the time most cars are driven in the city.
  2. The fact that as fuel economy on motorways peaks at < 60 mph, if we want to address NOx pollution from motorways, the peak limit should drop from 70 to 60.
  3. The lack of data we have on what percentage of Bristol's NOx pollution comes from buses and taxis. If we knew, then from a pollution perspective, that could be an area to focus on.

To close then, we congratulate Pointer2null for digging up an interesting paper on the impact of 20 mph limits on city of london's pollution levels, and may email the authors asking for any planned recalculations.

Assuming that Pointer2null going to become the city's advocate of pollution-scient-driven-transport policy, we also hope to see any papers they can now dig up on effective speed limits for fuel economy and pollution on motorways. Now that £80M has been spent on the Managed Motorways, it would now be possible to drop the speed limit there on high-smog days. Having some insight into the effectiveness of this would be something to help shape regional transport policy.