Thursday, 15 November 2012

Final possible candidates: Dave Dobbs and Phil Plover

The election is here today, and it is everyone's duty to get down there and vote for someone.

One option is Dave Dobbs, who cites is place of residence as a van in Stokes Croft. That's his key positive feature. If you've seen the flyer about how he believes a great flood came from Mars, well, he's clearly barking mad. But so is Gideon Osborne! And Michael Gove! And they have even more power and influence.

Being totally off your rocker should not be a barrier to holding political positions.

Anyone else: Phil Plover.  He's the candidate from the Waltham Forest party.

We had a look at his transport "ideas", as it's the one we care about.

"It might be good if Bristol gets some sort of rapid transport system – maybe trams or some sort of monorail. "

A monorail. People would laugh at as. Has never tried the one at Birmingham Airport?

" Open up bus-lanes - these are typically empty most of the day whilst the lane next to them is chock-full of slow-moving congestion, spewing pollution out for twice as long as necessary!
  Trams never needed a whole lane to themselves, laying empty 99.5% of the time. So, treating car drivers as sensible people who do care about the environment for them and their children, I would like to suggest a deal with Bristol motorists: when you see a bus behind you, pull in and let it pass - like you would an ambulance. It adds only seconds to your journey time!
  That way, we don't need to waste roadspace on separate bus lanes springing up all over the place, and ALL lanes can be available to ALL traffic, ALL of the time.   Simple, safe and sensible. 
This is good. the exclamation marks show him as one of those evening post commenters who can solve the city's issues with the word "simple!!!" at the end of every sentence.

His key idea here is that people should drive down a bus lane, but when a bus comes up behind them, to get out of the way. It's an interesting idea, let down by his naivety
  1. Bus lanes are for short stay parking; you can't drive down them for that reason. This is why buses are usually in the car lane.
  2. If you've ever seen an ambulance trying to get up Stokes Croft to Cheltenham Road in the evening rush hour, you'll see that people don't get out of the way for it. When they do, each lane pulls to one side, the left hand side half up on the pavement. Nobody is going to do that for a bus, unless it too has sirens and flashing lights.
"Make junctions more efficient ("1 in – 2 out") - to avoid delays and make travelling more efficient for everybody, where there is room, divide traffic approaching a junction into two lanes."
What he seems to mean here is actually have two lanes approaching a junction -as this will make it more efficient.

unfortunately, he appears not to understand basic queue theory -not even the wikipedia article. For Mr Plover then:
  1. A queue develops whenever the number of items leaving a channel (i.e a road) is less than the number entering it.
  2. Widening the approach to a junction is simply "making a wider queue". It does nothing to the overall throughput.
  3. With a wider queue, the jam may not appear as long, but it has the same number of vehicles, the same egress rate -and hence the wait time is the same.
Or to summarise: making the approach to a narrow road wider makes no difference whatsoever to your journey time -unless it encourages more people to drive that route in the belief it will -which will then make things worse.

People complain that politicians have no understanding of maths and science -this person is, sadly, an example.
"Where pavements are excessively wide, reduce them to 4-6 feet and create free parking space, where possible (except where large pavements are used by the community eg Gloucester Rd)"
We don't know where he lives, but in the inner city we view all pavements as parking spaces


Increase free parking wherever safely possible - I believe there are a lot of parking restrictions (double yellow lines and meters) where they don’t need to be – consequently, that roadspace is often underutilised while motorists drive round and round, increasing congestion and pollution, seeking an alternative.
We love this "its the restrictions that cause pollution" -theme, we'll have to use it ourselves. It implies that we do care about pollution as we drive our diesel van with the broken exhaust round the city, leave it running while we deliver some special toys to our customers -and it's all down to the fault of the council that small children die of asthma.


  Open up as much roadspace as possible so people can do what they need to do and go home again

we find parking restrictions like double yellow lines no barrier to "doing what we need to do:
 

Controlled Parking Zones (CPZ) – personally, I would find the idea of having to pay to park in my own road very frustrating. It’s mainly a problem where parking is very badly restricted. If parking were freer, it might not be a problem at all. 
No, this is one naive little bunny. Those residents of the expanding CPZ zone aren't paying 30 quid a year for the right to park outside their house -they are paying for the right to use their car during the day -because they can be confident there will be somewhere near their house when they come home. As for the "problem where parking is restricted", no -is where there isn't enough room for all the residents and commuters, even when the pavements are fully utilised (e.g. montpelier)

There' s a risk here that the "motorists drive round and round, increasing congestion and pollution" theme could come back to haunt him here -in a CPZ, there is no point driving round. Hence the pollution and congestion falls.

The whole theme of this manifesto is that the author doesn't live in the city -he lives in one of the suburbs and gets really frustrated sitting in a traffic jam by an empty bus lane, when he gets into town gets angry the only free spaces have double yellow lines, or you have to pay to use -and that his secret near-centre parking zones are being made residents only in a deliberate attempt to make his life harder

Remove large slabs of concrete - Surely squashing vehicles closer together can't make sense. If there's room to keep vehicles further apart, that reduces the risk of collision and means you have somewhere to go in case of emergency (eg a child or elderly person falling into the road).
It turns out this means "remove the build outs that force you to slow down entering quieter roads"

There's some interesting maths here; a mix of game theory (conflict and reactions to collision risk), and probability. Specifically that "somewhere to go in case an elderly person falls into the road"

With a wider buildout, there is more pavement for the elderly person to fall onto, so P(fall-into-road) is reduced; with the reduced cornering speed the energy in the collision is also reduced. Phil's assertion "you have nowhere to go in an emergency" implies that swerving is the tactic, not braking, and that there is no oncoming traffic, so swerving is a viable action.

If you do swerver, not break, then the original amount of energy going into a person falling into the road depends on the probability of you hitting them

e = P(falling)*(1-P(swerving))*mass*velocity^2

In  the new layout
e' = P(falling')*(1-P(swerving'))*mass*velocity'^2

We'll leave it to the readers to work this out -the quick summary is obviously that the velocity-squared variable is the main factor in damage; the probability of swerving out the way would have to get four times worse to result in the same damage reduction as cutting vehicle speed in half.

Sadly, as Phil Plover doesn't get queue theory, probability and statistics will be beyond him too.

There we have it then. The candidate for the evening post commenters. Someone whose entire world view is based on "obvious" answers, yet without the basic mathematical underpinnings to recognise that his obvious is, to us, obviously wrong.

Dave Dobbs it is then!

4 comments:

Unknown said...

From your link, Dave Dobbs is clearly crazy. He seems obsessed with security vulnerabilities in popular peer-to-peer communications systems and doesn't even mention Bristol at all.

SteveL said...

fixed!

Rhode Long said...

Maybe Phil Pover is Freewheeler's alter ego. He has been remarkably quiet since the mayoral campaign kicked off. You would never suspect...

"Unknown" says that Dave Dobbs is clearly crazy. I think not - this is what he wants you to believe. Reading Phil's manifesto then suggesting doing the same thing again and expecting a different result (and assuming the motorists are going to be nice to buses) is certifiable!

between-the-lines said...

Yeah, cos like freeing motorists from parking restrictions is such a simple, brilliant idea - just ask the people of Aberystwyth about their experiment ...

http://www.dailymail.co.uk/news/article-2153430/When-Aberystwyth-experiment-created-world-traffic-wardens.html