Wednesday, 22 May 2013

Traffic lights on roundabouts, cyclists and tinted windows

Bristol Traffic does have a twitter account, which rarely gets used for the following reason "to spend time on twitter is to waste an important life". Yet we do get notifications on messages sent to @BristolTraffic, as it is a way for little people to contact us. We obviously care more for little people to call up our Stokes Croft "adult content" fulfilment centre, get redirected to our Luxembourg sales office for Bristol Traffic s.a.R.L, buy entertainment products from the tax-efficient locality and then have us deliver them to anywhere within the former Avon county.

Today, we get a tweet from one Andrew Fawkes:
@bristoltraffic Would you like to R/T this? Even turning them off at peak times would help congestion! Thank you.
Pet hate: traffic lights on roundabouts. RBs were designed to keep traffic flowing. Please r/t if you agree and let's keep traffic flowing!
@AndrewWFawkes is proud to be a "Marketing consultant, career coach, classic car activist, MotoGP fan, guitarist & singer in a band and lots of other spare time activities!", based in Somerset UK".

Somerset is of course the elf-kingdom, which is where important people live, despite the fact that Bristol council is trying to push bike lanes into the kingdom -against the elf-folk's wishes. Everyone who commutes in up the A370 gets stuck somewhere in the way by anti-car policies of the inner city.

The traffic lights on roundabouts are merely a detail -and not one we care much for ourselves.

We are actually against them for a number of reasons.
  1. By making it safer for cyclists to cross, they make it easier to cycle round the city, so encouraging cycling.
  2. The James Barton Roundabout has a special light for buses coming from the M32 direction, so encouraging bus use.
  3. Sometimes we have to wait at them for up to 30s
  4. Sometimes when we pull out just as it goes red, our van blocks other traffic who then get upset.
  5. The lights on the James Barton and St Pauls roundabouts are still on at 4am, where the only traffic is our van on an emergency delivery of inflatable sex aids to some of our St Andrews customers.
What we aren't sure about is the idea that turning them off at peak times would help congestion.

Having to put traffic lights on a roundabout is an indication that the roundabout has entered a failed state; that without them you woudn't get fair access to the roundabout.

Because a feature of a roundabout is that you can pull out, which can only be done if one of two conditions are met
  1. There's nobody on the roundabout.
  2. The roundabout is very busy, but traffic is exiting onto your road, so you can pull out as they turn off.
At peak hours, the "nobody on the roundabout" condition is not met, so we depend on the "traffic exiting" condition.

If people don't turn off onto your junction, you don't get out -leading to what is known in queue/scheduling theory as starvation.

For anyone trying to cycle over a roundabout when someone pulls out, this is why we do it. It's not just because we hate the cyclists for being there and not paying -it's because the only way to pull out in a busy roundabout 

Here, for example, is the car AE59JGU pulling out in front of a bicycle on the St Michaels roundabout. It's not that they didn't see the bicycle -it is that it was a weekday morning, and the only way to get out was to cut up the cyclist. There was no reason for the cyclist to catch up with them and say "please don't cut me up like that -it makes you look bad in the video". That was just selfish behaviour by a cyclist that shouldn't have been there.

While covering this incident, notice that the car had tinted windows. This is a great feature from a game-theory perspective, as it introduces more uncertainty into the negotiations. There is no way the tax -dodger could make eye contact with the driver, to see them and for them to see you. Instead, the dark windows depersonalise the car " there is nobody in there that cares -this is only a machine", as well as stopping the cyclist from even imagining that they've been seen.

Given that uncertainty, slowing down is the only thing the tax-dodger could do -creating the opportunity for the audi to pull out. Such an incident discourages the city-folk from cycling, so making easier for commuters from the Elf-Kingdom to come in to the city and so create wealth.

To summarise then:

  • Traffic lights do hold up traffic, but not always at peak hours, as they make the scheduling of junction ingress fairer.
  • If the council does remove them, we have to correct for this scheduling by pulling out when you don't have the right of way
  • Cyclists are much safer to pull out in front of than buses
  • Tinted windows are great for reducing the confidence of cyclists, so making it easier to pull out in front of them.

Andrew -thank you for your opinions! We have summarised our views on the matter!

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