One of the "Pickles war on the war on motorists" issues is that the lack of free parking is destroying the high street. An interesting assertion, but is it backed with real data? Well, we like our data over opinions, especially when the opinions come from politicians, national or local, which aren't backed up by any evidence.
Here is whiteladies road on a weekday, from Clifton Down shopping centre up to Blackboy Hill, or more precisely the Port of Call pub.
Some things to observe.
0:00 starts at clifton down, where a mid-size Sainsbury's provides groceries and beers.
The first 1:15 of the 2:30 video contains a stretch with vast amounts of short stay parking for shoppers. With the roll out of the bus lanes, the commuter parking here is now gone.
The first 1:15 of the 2:30 video contains many vacant shops. Two camera shops -killed by digital cameras eliminating the printing business, and Amazon. One bookshop: killed by Amazon. A bottoms-up off license. Some clubs which went away when "the strip" fell out of fashion.
The upper half of the video contains lots of shops -even though the parking spaces there are all full. It includes esoteric shops: kitchens, ellis brigham, artists supplies premium things: a fish shops, a cheese-vendor, and everyday things.
The implication here is not that a lack of parking kills shopping, but that online trading and digital devices has destroyed the business models of some shops, trends in nightlife (and the cash to party) others. The 2008 banker-created recession has probably been more destructive than anti-car policies in this road.
Another issue may be that the Sainsbury's sucks up all the daily shopping cash, leaving only outdoor coffee shops nearby and a post office/chemist. The upper section of the hill keeps going due to a large local resident population with enough money to buy things, and the fact it contains the last off licenses, pubs and chip shops before the downs, or more precisely the student halls of residence on the other side of the downs.
(footnote: one of main camera of this project, a panasonic TZ27, came from Jacob's cameras which was at 0:54. London Camera Exchange in central Bristol is still surviving, showing that some of the more specialist camera shops are surviving -even though parking there is worse)
Some people -mistakenly consider us to be some kind of spoof, whereas in fact we are a documentary that has built up a weakly-defensible dataset of the city's transport issues.We also include topics like queue theory, game theory and the like to analyse that data.
This is why we despair when the legacy mass media publish articles that lack both real data and the fundamental understanding behind it
Now, Queue theory, Erlang's core concept: A queue happens when the egress rate of a channel is lower than the ingress rate.
In less technical terms "you get a queue if less things are leaving something than entering". It doesn't matter how big a bucket is, if more watering is pouring into it than is leaving from a hole in the bottom -eventually it will overflow
In evening post commenter terms "there's no point making something two lanes wide if it has to go down to one lane wide a bit further on". The bottleneck is the one-lane bit wide, not the two lane stretch.
We know this is hard to grasp, which is why people are still complaining about the Portway bus lane. Evening Post Commenters: the bottlenecks are the narrow bits beyond the suspension bridge and Anchor Road -removing the bus lane will not increase your journey time by car at all.
Alternatively: it is futile to remove a bus lane in the name of congestion, if there's a single-lane road later on. You are wasting your life on something that will not deliver the benefits you expect. You may argue against this using the term "common sense" -but that is why building things from bridges to computer networks rely on people called "engineers" trained in something called "mathematics". Common sense doesn't cut it when you actually want something to work.
The Evening Post reporters need to pick this up too.
A BRISTOL campaigner claims a set of traffic lights at a busy junction cause more congestion than they solve – and should be ripped out. Simon Brookes, who led a campaign for the removal of a controversial bus lane in Westbury Road, is now calling for the removal of the lights at the top of Blackboy Hill.
We aren't sure what "campaigner" means here. Presumably it means "someone who doesn't understand queue theory but likes to get their face in the regional press"
He conducted a survey and claims that the lights held up lots of buses.
Mr Brookes carried out another survey yesterday between 9am and 10am. He said he witnessed 89 changes of the lights and during that time, only two buses went through on green. But the number of buses going uphill and held up on a red was 26.
We are surprised that Mr Brooks has now started caring about buses. Because if you are trying to get bus lanes removed on the approach to Whiteladies Road, suddenly caring about their performance in Whiteladies Road itself seems somewhat hypocritical -unless you are simply pretending to care.
Furthermore, if you are going to do a survey on congestion -why do it outside the rush hour. Do it at 08:30 at peak commute and school runs. Doing it after 9am is like saying the M32 doesn't get congested because you drove up it on a sunday morning.
Bad data, failure to root cause analysis and then pretending to care about public transport. We don't do any of these.
Mind you, Mr Brooks' pretence to care about buses doesn't make it through the article:
He will also be calling for a cycle lane to be removed from Westbury Park, where it meets with North Road. He said the lane was not used by cyclists and simply added to traffic congestion. Mr Brookes also wants to see the removal of the remaining stretch of bus lane from Westbury Park.
Sorry, but the congestion has other causes. It may seem frustrating to be stuck in a car watching bike lanes and bus lanes that are empty most of the time, but that is because they are working. The buses are not being held up until they merge with the cars on Whiteladies road; the bicycles not held up at all, mostly.
Here then is our dataset: a video from "wheels on the bike" counting the entire set of vehicles on Whiteladies Road, from the top to the triangle, in 1:45.
Most of Whiteladies road is one lane wide. That is the bottleneck -the carrying capacity of the road. Arguing about bus lanes up the hill or even switching times of traffic lights is irrelevant when there is a lane traffic jam from Park Row and Park Street stretching all the way up to the Downs.
This is why appearing on papers demanding for things to be removed because they "cause congestion" is dangerous. Someone may one day see this video and say "maybe there are other issues". We know that -it's the surburbanites driving into town. Simon Brookes should recognise this, and keep his mouth shut.
Having met the odd traffic planner/civil engineer in the past year, one problem is that they have a technical language to describe things, a language they use to communicate with their peers -but also to exclude those who are not educated in civil engineering. What to do? Josh Hart is going for the "learn the language" approach, by studying at UWE.
The rest of us don't have the time to do that. Instead I'm guest lecturing at a local university on computing topics, which is going to provide the answer. Instead of wasting time learning civil engineering concepts and terms, take software engineering/computer science terminology and apply it to traffic. The advantage of that is that you don't need to understand the details, to be able to handle the reply when you say "The O(1) scheduling algorithm delivers fairness but under 80% saturation the router tends to drop packets on the floor". Because if you are saying it to the traffic planners, they don't understand either. But it scares them. Which is important, as from the early findings, there isn't much in the way of science in traffic management; there's no experimentation. Just some simulation programs written in the early eighties based on inadequate data. That's a belief-driven approach, not the evidence-driven one that is the basis for sciences.
If it were a proper science, it would be data driven, from repeatable experiments. For example, before proposing replacing zebra crossings on Blackboy Hill with puffin crossings, they'd check to see if pedestrians would stop on the red light,. Once they knew what number of people would ignore the light, include that in their simulations and risk analysis. Then they'd stick up some temporary lights to see what happens to the congestion, before dropping a few hundred thousand pounds on it.
Anyway. Henceforth, this blog will sometimes introduce computing terminology for the reader. Enough to intimidate the odd traffic planning consultant. Especially once we start collecting the data they don't seem to have. First up: deadlock.
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