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.

Tuesday, 22 September 2015

VW TDi rigging: —but why?

The VW TDi rigging story is pretty serious; it's the third big automotive software disaster —and we haven't even covered disasters #1 and #2 yet.

Which are, for reference:

  1. Toyota's dev team being utterly incapable of writing software in accordance with modern software development practices  —with the failing accelerators being only one of the consequences of this. None of those people should ever be allowed to write code for anything more safety critical than a flash-based web advert ever again.
  2. Jeep's "Jeep Cherokee online edition", feature, where every model shipped in 2015 had a modem scannable on the network, an 0wnable infotainment console and an engine (on the same single network), whose network stack never once questioned why the mp3 player was sending messages to the transmission to turn itself off. Those engineers shouldn't be allowed to code for anything directly or indirectly attached to the Internet —which, in modern society, means they can't even code a light bulb any more (do watch that entire video for terrifyingly accurate summary of the current infosec world).
  3. VW's US TDi models detecting when they are pushed through their emissions control exam and so not being polluting for the hour or so it takes. (this would be good for MoTs actually; it would go down well with our business plan to rent VW wingmirrors for MoT tests)

Now, one of our team members does own an (ageing) VW TDi barge, and while it is frugal —even at 20 mph, we add—, it has some limitations, specifically it is a lot less responsive than the VW Passat 1.8T "wagon" which used live in the double garage up in the Pacific North West. That car had a ski box in the roof, Z-chain snow chains in the back and the ability to make it from that garage over the mountains and into in he car park of the ski resort in 2h30, —all for less than $20 of "gasoline".

Because that is the surprising thing about the US adoption of turbo-diesels: from an EU perspective, the US give away free fuel to their citizens.

Being evidence driven, here is our evidence, a receipt from ten-days into the Bristol-Traffic-strategic-meetup-with-the bay area self-driving-car/police state manufacturers. Driving, for reference a VW Jetta 2.0 16v petrol engine with automatic transmission rented for $250/week.

This is for seven days worth of commuting across mountain view, 30 miles a day,  plus the weekend leisure activities silicon valley is famous for (going to shopping malls and buying new apple hardware in the belief it will make your life more satisfying).

Assuming 150 miles over the weekend plus the commute, 30x7 + 150 = 360 miles.
The receipt is for ~13 US gallons, 27 mpg. In UK Gallons, that's 32.7 mpg. Not bad.

Now look at the total cost, $44.32 —that's £28.63. For 11 UK gallons. Which is £2.65/gallon —or, more tangibly, 58 pence a litre.

58 pence/litre? And people think the fuel economy of that car was so bad that they had to switch to a TDi model with higher economy. That is, they felt "gas" was so expensive that they had to pay a premium for an engine with more cabin noise, bounces up and down more when you are trying to text at traffic lights and whose overtaking ability, once you consider the gear-drop and turbocharger spinup will only take place once you actually hit the accelerate pedal, isn't actually that good. In contrast, a petrol Jetta is, compared to a UK petrol-engined Golf, half the price per mile and equally nimble, albeit somewhat crippled by its saloon-car design preventing it being so good for throwing things in the back or for parking in smaller spaces. You would have to be doing a lot of long-distance driving to actually justify swapping the petrol engine for the diesel turbine.

That's what VW managed to pull off with their software: not the rigging of the emissions —but the convincing of the US customer that they'd actually have a better time in a Turbo Diesel.

Sunday, 30 August 2015

Bristol vs Self driving cars

One little sighting over by our strategic PCSO-state partners, Google, are their self driving cars.

They are utterly not-ready for Bristol. You can see this at a glance

Not only is there a bollard on the roof, there appear to be sensors coming out of every corner.

Here in the city centre we have a word to describe vehicles with wing mirrors attached: visitors.

While having wingmirrors helps you in certain out of town operations, primarily changing lanes on the M4, in town it actually hurts you: it makes your car about 30 cm wider so significantly reduces your choices as to where to drive. And, as their presence broadcasts that you are not a local —but instead have a vehicle you care for— you lose every negotiation that takes place, be it a junction or a "who will give way first" interaction. And, when parked, you don't have to bother looking out the window when you hear the sound of a car-on-parked-car interaction, unless it is so loud that you fear it may be some damage needing bodywork repairs.

Now put something on every corner of the vehicle whose presence is actually critical for the self-driving feature to work. Sensors attempting to detect what is too close, so the multi-layer neural network that is is google self-drive program can make a decision as to what to do next.

It's doomed.

That's before even looking at what complexity of road the cars are exposed to. This road, "Castro", is a complex environment on the basis that it actually has people walking. Yet it is wide-enough for oncoming vehicles to pass each other, all junctions are nice simple right-angled crossings, and visibility is reasonable.  Now imagine taking a car trained here and trying to drive down Clifton Vale, the one with the blind z-bend you have to share with oncoming traffic. The car would just give up. And it would share the experience with every other google car, saying "avoid this road". Before long whole swathes of the city would be blacklisted by Google cars, cars who give up on account of their paintwork and external mounts being valued.

Which, when you think about it, could be no bad thing

Saturday, 29 August 2015

where are the speedo-watching crashes?

Here are the two petitions to look at

Speeders: Scrap the 20mph limit in Bristol and restore common sense  now at 8045
Keepers: Keep and extend 20mph limits now at 1680

One claim in the Speeders' petition is
"roads will only be made more dangerous with frustrated drivers and people watching the speedo rather than where they're going!"
We haven't noticed that ourselves, as we have a special speed limiter in our car called "the gear stick". Put it into "speed band 3", or "3rd gear" as it is sometimes known and it burbles along quite happily at 20-24mph, except in the special case that someone drives so close that you can see the driver's nostril hair and you slowly lift your foot of the accelerator to drop to precisely 19 mph just to see the expression on the driver's face in your rear view mirror.

Anyway, it may be that the speed petitioners don't have manual transmissions, or are somehow unable to determine road speed, and do have to look at the speedo all the time.

This is something we can test now that the central 20 mph zone is over a year old. All we have to do is look at the data.

One irony here is that if they do occur, the fact that they will take place at 20 mph means the police aren't likely to get involved. Any crash involving pedestrian, cyclist or stationary object will be less likely than at 30 mph to injure anyone, so they may not get called out. Indeed, even the insurance companies may not get a look in if people care about their no claims discount. head-on collisions will still have 40-50 mph of energy, so are more likely to show up. This means official data sources: —police and insurance— may show a reduction in RTCs even if there has been an increase in RTC events.

We ask the speeders, then: where are the speedo-watching crashes?
  1. How many crashes in 20 mph zone have you personally been involved in where you or another participant was looking at the speedo at the time?
  2. Have you heard of any such crashes —and do you have the contact details for us to follow up on this?
  3. Is there any other evidence for an speedo-watching crashes in the central bristol zone?
We've had the zone for 18 months now, with millions of journeys in it by now. If speedo-watching crashes are a risk in 20 mph zones, we should have seen some. 

If we don't have the any signs of speedo-watching crashes, then, it could be due to
  1. They are happening, but the massive lower energies in the collisions cause them to be unreported
  2. That whole claim about "watching speedos causes crashes" is bollocks.
#2 is the null hypothesis: 20 mph limits do not cause speedo-watching crashes, is the one which has to be disproved to a significant degree of statistical confidence before it can be believed.

We put it to the speeders then: show us the data.

Now, assuming, on the off-chance that there is the data, that speedo-watching does cause crashes, hence 20 mph zones are more hazardous than 30 mph zones, why do the petitioners still propose lower limits by schools?

Either 20 mph zones are more dangerous due to speedo-watching or 20 mph zones are safer round schools.

So if that claim "20 mph is more dangerous" isn't utter bollocks, then, if the speed campaigners really believed it, they should be pushing for 30 mph zones round schools "for the children".

Speeders: show us the data —you've had 18 months to collect it.

(photo: kid scootering to school outside Christchurch School, Clifton, pre-RPZ)

Friday, 28 August 2015

Unhappy speeders

In our ground breaking analysis of the geographic distribution of the speeders and the 20 milers in the city,  we were picked up on for our statement "They must live very unhappy lives."

Good catch. Judging by the reaction to the post, we should have concluded "they are very angry people"

It's as if they spent a lot of time in traffic jams or stuck at the lights -blaming George Ferguson for every minute of their wasted life

We were particularly called out on our assertion that the 38% of out of town petitioners on the "right to speed" campaign don't count.

Specifically, the accusation of misinformation came about because of the T&Cs of the council's petition policy, which states
If your petition has received 3500 signatories or more from people who live, work or study in Bristol it can then trigger a full council debate [see page 5] and if this is the case we will discuss with the lead petitioner the options for enabling this to take place.
We are not attempting to misinform anyone. Look at what we wrote
Of the speeders, 38% of them don't live in in Bristol. Which means they are, as far as Bristol elections are concerned, as relevant as residents of the Isle of Wight. They don't have a vote, all they have is a whine.
See that? If you live outside the city, you are electorally irrelevant. Which may or may not transfer into the decisions about the region and its transport policy.

If you lived out of the city, you wouldn't have got a bit of a paper asking if you wanted a referendum on having a mayor —you didn't get a say. You wouldn't have got a bit of paper saying "who do you want to be mayor" —again: you don't get a say.

The fact that the council has a policy for petitions is something to cherish. The fact that they even let people from outside the city add their names shows that we do value those people who live out of town. But when it comes down to whom the council has to prioritise, it's the residents who vote for the councillors and mayors.

Everyone outside gets to make a whining sound, either in their own home, the BEP web site or their car sitting on the M32.

Is that fair? Maybe. Is it functional? Not for a region wide transport policy. But here's the problem: the N Somerset and S Gloucs councillors like their little kingdoms too much to share them.

Here we see Elf-King App Rees switching from demanding that the Clifton RPZ be removed screaming that George F is trying to dictate parking policy in Leigh Woods.

He loves being a small fish in a very small pond, and any attempt at having a broader region for  democratic governance as a threat.

Is S Gloucs any better? Well, they are very proud of the the fact that they are not quite Bristol, even to the extent of having a "Welcome to South Gloucestershire" partway along the Filton Road weekday traffic jam. Because Filton is, after all, distinct from its neighbours. But they do ask staff at the N Fringe of the city for their input on the latest bit of random roadworks.

What is not clear, though, is Why is Filton out of Bristol? . Same for those bits in N.E. Bristol. Emerson's Green, Rodway Common, etc. Part of the featureless hinterland of the city. And yet: you don't get a say —only the right to get angry about things happening in a city nearby.

Those pro-speed petitioners: do their opinions count? Not for 38% of them, no.

We've stated repeatedly we are Bristol's premier data-driven transport new outlet, compared with the evening post, which is driven by "what gets the most paper sales to our dying customer base" and "what generates the most page hits". Controversies involving parking, cyclists and speed zones hit all three.

Sadly, we don't have access to the BEP customer dataset or the details on commenters they extract from their linked-up google accounts. What we do have, however, is the python code needed to convert the published signatory list into a CSV file, with some extra flags to indicate whether or not the petitioner is in a 20 mph zone or not.

            20 mph ward  rest of BRS  CUBA    other 
Pro            920         305         116     201
Speeders      1552        3365        2289     705

As a graph, showing the numbers by area, things become more obvious

Of the speeders, 38% of them don't live in in Bristol. Which means they are, as far as Bristol elections are concerned, as relevant as residents of the Isle of Wight. They don't have a vote, all they have is a whine.

Looking at Bristol itself, we see a marked split between those people in wards with 20 MPH zones vs those which aren't.

Even though the pro-20 MPH petition is a fraction of the size of the speeder's one, it is not far off having 40% of the total petitioner count from the 20 MPH zones themselves.

This implies some things
  1. The people who get most worked about 20 MPH zones don't appear to live in them.
  2. Many of the people who get worked up about Bristol's 20 MPH zones don't even live in the city.
  3. They must live very unhappy lives.
  4. A lot of the people in the 20 zones seem pretty happy with the zones and their lives.
We'll collect some more data next week, and make up some new conclusions. Until then,  get out there and get some signatures for whichever petition you care about.

Monday, 24 August 2015

The 20 mph war on our council web site

There's now a battle of petitions up on the council web site

The scrappers: , "scrap the 20 mph limit and restore common sense",

We love the use of "common sense" in the title. "Common sense" means "obvious to the person making the statement". Yet, as we look throughout history, "common sense" meant the sun went round the earth. Galileo's Heliocentricity hypothesis was considered so heretical the common-sense regime at the time (Catholic Church) sentenced him to death. That's what common sense means: superstition over rational thought.

The retainers, "Keep and Extend 20mph limits"

These want the limits retained, extended, and maybe even enforced. We will call these "the people who believe Newton's equations about momentum and kinetic energy".

There we have it then, two factions: those who reject the physics of RTCs on the grounds of "common sense", and those who care about people walking and cycling round the city.

It will be interesting to watch the numbers. the flat-earthers have the support of the local paper, and a three month head start in the petition.

As of June August 23:

Flat earthers: 7421
Progressives: 1053

This is something we'll be keeping an eye on.

Saturday, 8 August 2015

Traffic Cameras: they don't shoot black americans

One of the recurrent themes in the UK press, with the Daily Mail-esque "Speed Cameras steal from motorists" story also recurring in the US,

Usually there are people quoted demanding instead real police, in real police cars, catching people "really" breaking traffic laws —by which presumably they mean "people other than themselves"

What doesn't get covered, though is how scary it is to be stopped by the US police compared to those in the UK. In the UK you get pulled over with some opening gambit like "is this your car, sir?", or "how much have you had to drink this evening?".

In contrast, in the US the lights go on so bright, with such a loud siren that you look up from your phone with a jerk, to see the police car filling your mirror and pull over in fright. Only here, the police officer (almost invariably a white man) walks over with their hand near their gun, ask you to wind down the window and then keep your hands visible, all the while standing a bit behind the door so that you are in front of them and its easier for them to shoot you than vice versa.

It is frightening, and you have to be so careful not do to anything not to make them overreact, and reach for the gun. And that's just as a white adult male in a nice car in a nice part of the US.

Now imagine you are an 18 year old black american being stopped at night. You know the police have a track record of shooting black americans even when pulled over for "minor traffic misdemeanours".  This is a country where failing to indicate as you change lanes has a death penalty.

You are going to be scared whenever you get pulled over, if you look at the statistics from places like Ferguson, you will be pulled over a lot more than white americans, and the is a small but tangible risk of you not getting out the stop alive.

In contrast
  1. Traffic cameras don't pick on drivers because of their skin colour or age/state of vehicle.
  2. Traffic cameras don't shoot black americans. Or any american, to come to it.

While in suburban americans may scream about unjust and unfair traffic cameras, you might find some locals with different opinions. Ask black americans kids whether they'd prefer being stopped by the police with a risk of being shot or having traffic violation fines sent in the post —you may find more support for the cameras. Now ask their parent, those parents who worry about their children going out for drives at night in the US, and they may give a very different answer.

Traffic Cameras: they don't shoot anyone

Visiting our strategic partners in Mountain View, California

We've stated before: with our strategic partners Google and Facebook we are building a PCSO state, one where people pay month for the privilege of being monitored, such as the how your Android phone reports in your movements 7x24.

We do of course have to visit our partners sporadically to brief them on developments, hence a short trip to the US. Expect some commentary as well as insights from Silicon Valley, which is now the hub of the future automobile. Even watching people gives us a profound vision of the futre

First, how to carry furniture in a "convertible"

The correct approach, clearly is to stick the chair in upside down, with someone on the passenger seat to keep an eye on it. The driver themselves gets some information on the chairs status: if they look in the wing mirror and see daylight then the chair has gone. If they hear over their music the sound of brakes and crash, they may also get an audible cue of the "chair loss event"

Until then, luggage transportation at work.

We just have one outstanding question though. We've seen them carrying a chair. What are they going to do with the Sofa?