Transportist: October 2023
The elites want to keep the masses in ignorance. The criminalisation of the 'original sin' punishes humanity for seeking knowledge.
A lively month on Transportist.
In this issue:
Posts
Traffic Signals
Fantasy Forecasting Further Follow-Up
Computational Irreducibility
News
Posts
Traffic Signals
Declan Bowring at ABC News picked up on Jake Coppinger’s great Better Intersections project. (All news stories are discovered via Reddit it seems). This is a project that should not need to exist, but alas, the SCATS crew has yet to make their data public, nor consider pedestrian delay in their algorithms. I got interviewed for the story,
University of Sydney transport researcher David Levinson said wait times discouraged walking as a means of getting to places.
"If in 10 minutes I've wound up waiting at two intersections or four intersections for a minute each, then I can only go 600 metres in that time instead of a full kilometre," Professor Levinson said.
"The longer you wait, the more annoyed you feel."
Professor Levinson said there were a few tweaks that could be made to intersections to make the city more friendly to walkers, such as the pedestrian light turning green before traffic lights did.
"This means pedestrians get a head start and are visible to cars that are making turns," Professor Levinson said.
"Countdown timers are another good practice that can be done."
and then live on ABC News midday Monday Sept 25, in an interview so forgettable not even the University of Sydney news service picked up on it.
This article from five years ago does a more comprehensive job explaining the issue. Nothing changes.
Some other related interviews
“In Australia, the walking speed used to determine pedestrian walk time and pedestrian clearance time is usually 1.2 metres per second to 1.5 metres per second,” says David Levinson, Professor of Transport at the University of Sydney.
When asked if it’s reasonable to expect all people to be able to walk at this pace, and whether the guidelines accommodate those who fall outside that range, Levinson says they do not.
“It’s all designed for 95 per cent of people, with the bottom 5 per cent forgotten,” he says. “The world is designed to hurry you for the benefit of someone else. But, not everyone wants to feel hurried,” he says.
Fantasy Forecasting Further Follow-up
Faithful reader Jarrett Walker reminds us of this paper:
Walker, J. (2018). To predict with confidence, plan for freedom. Journal of Public Transportation, 21(1), 12.
What will urban transportation be like in 10-20 years? How will automated vehicles interact with social and cultural trends to define the city of tomorrow? Will the vehicles of the future be owned or shared? How will pricing evolve to motivate behavior? What will happen to public mass transit? What other innovations can we expect that will transform the landscape?
This paper, which is merely the outline of a larger argument, suggests three interconnected answers.
We can’t possibly know. History has always been unpredictable, punctuated with shocks, but if the pace of change is accelerating, then unpredictability may be increasing too.
We can reach many strong conclusions without knowing. A surprising number of facts about transportation, including some fairly counterintuitive insights that would be transformative if widely understood, can be described and justified solidly with little or no empirical ground, because they are matters of geometry and physics or of nearly axiomatic principles of biology.
Prediction may not be what matters anyway. If we abandoned hope of predicting the future, we could still describe a compelling outcome of transportation investment, one that motivates many people who will never care about a ridership prediction or economic impact analysis. We could also predict it in the sense that we can predict the continued value of pi. That idea is freedom, as transportation expands or reduces it.
Faithful reader Juan de Dios Ortuzar writes:
With Luis G. Willumsen in Modelling Transport, we recommend the use of a “continuous planning approach, and the need for a monitoring function.”
Faithful reader (but no doubt now disappointed in me) Tom van Vuren defends his peers in “Are modellers fantastic – or living in a land of fantasy?”
Computational Irreducibility
We probably should spend some time on the idea of “Computational Irreducibility”the expression was probably introduced by Stephen Wolfram, though I believe the idea itself is older. It posits that some processes or systems are so complex that the only way to determine their outcome is by directly simulating or running them, rather than predicting their outcome through a shortcut or a simplified formula.
It is in contrast with computational reducibility, which is pretty standard in traditional science, that systems can be broken down into simpler components or described with equations that allow for predictions without directly observing every step. These are computationally reducible. Computational irreducibility, on the other hand, suggests that no such simplification or shortcut exists for certain systems.
A classic example is certain cellular automata rules, where to know the state at step 1,000, you might need to compute all 1,000 steps rather than skipping directly to the end using a formula.
In systems that exhibit computational irreducibility, it becomes challenging or impossible to predict long-term behavior without running the system's entire evolution. This limits our predictive power.
Computational irreducibility implies that even if we understand the underlying rules of a system perfectly, it doesn't necessarily mean we can easily predict its future state.
So the question arises, are systems with a large human component (like, say, cities, or transport networks) computationally reducible, and to what extent? While there are some equilibrium-seeking (negative feedback) elements of transport networks (user equilibrium in route assignment (which I remind everyone does not really exist, but is an approximation), the equilibrium (feedback) between destination choice and route choice that gives us induced demand), these are hardly perfect. In contrast, the Fundamental Model of Access is largely a positive feedback system, which is the antithesis of being computationally reducible.
Research
Chen, Jing and Cui, M. and Levinson, D. (2023) The Cost of Working: Measuring Physical and Virtual Access to Jobs. International Journal of Urban Sciences. [doi]
The COVID-19 pandemic has increased the incentive to work-from-home (WFH) in many countries and well-developed information and communication technology (ICT) provides strong support to do so with no need to physically travel to workplaces. This paper defines the concept of physical (traditional) and virtual (online) access to jobs based on dual access theory, by analysing different job profiles to recognize those that are capable of working from home and those that are not. A theoretical framework is then built for physical and virtual access measures and applied to the Minneapolis – St. Paul (Twin Cities) region. The results show that virtual access is much more sensitive to its cost variables, like wage change or at-home working space, while physical is less affected accordingly. A suburban ring emerges, which enjoys better access to jobs when physical and virtual working are mixed over a week. The results provide insights for planners, managers, and policymakers.
Gao, Yang and Levinson, D. (2023) Lane changing and congestion are mutually reinforcing. Communications in Transportation Research, Volume 3 Number 100101 [doi]
This study presents a comprehensive analysis of the relationship between congestion and lane changing, using vehicle trajectory data from the M1 motorway in Sydney. We establish a connection between the distribution of travel time and lane changing frequency and employ a Poisson process to describe the intensity of lane changing occurrences in different travel time ranges. From an individual perspective, lane changing does not bring significant speed benefits in most cases, except when the speed range is between 45 and 50 km/h. From a system perspective, the relationship between lane change rate and speed depends on the purpose of the lane changes. In merging, diverging, and lane restriction areas, for instance, mandatory lane changes dominate. In most sections of the motorway, discretionary lane changes are motivated by the expectation of improving speed and/or safety. Additionally, we demonstrate a mutual causality relationship between lane changing and congestion through the Granger causality test. This relationship is more pronounced in general areas during peak periods and contributes to the deterioration of the driving environment.
News and Opinion
Comics
Urban Planning Opinion Progression XKCD
Infrastructure
Aviation
Alan Joyce leaves Qantas, departure delayed because [insert excuse here] (not enough blankets on-board was my favorite)
Sharing
Surge pricing has lost all meaning (by Oversharing)
Lime claims a profit - IPO Coming
Work from Home
Fully remote workers could produce less than half the climate-warming emissions of people who spend their days in offices, according to a new study published Monday in the journal Proceedings of the National Academy of Sciences.
Hypothesis: people do lots of non-work errands on the 1 day WfH but don’t need to do that 5 days a week. Still leave home, but not as much.
Automation
Electrification
Dynamic Wireless Charging is progressing: