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Transportist: End of the year extravaganza
An Airing of Grievances
This is the last weekly post until the New Year. Enjoy the holidays for those who celebrate.
Ji, Ang, Ramezani, M. and Levinson, D. (2022) Joint Modeling of Longitudinal and Lateral Dynamics in Lane-changing Maneuvers. Transportmetrica B: Transportation Dynamics. DOI: 10.1080/21680566.2022.2154717 [50 free online copies]
This study models a lane-changing event as two behaviourally intercon- nected phases: ‘stay’ and ‘execution’. The model considers the ‘stay’ phase duration stochastically depending on external traffic conditions. The ‘execution’ phase is modelled as the longitudinal speed profile deployed to perform the lane change. The model comprises a Bayesian survival analysis to predict the probability of the stay duration before a new ‘execution’ phase while tackling the censoring issue of survival methods. Using naturalistic vehicular trajectory data, this paper quantifies what factors influence driver behaviour in lane-keeping and lane-changing execution. The parameter estimation results demonstrate that drivers’ decisions on phase transitions are influenced by surrounding conditions, lane-changing purpose, directions, and departure lanes. The findings reveal that urgency (stemming from the purpose) and patience (satisfaction with the existing situation) are the main reasons for leaving the current lane. Adequate distances and relative speeds compared with surrounding vehicles induce or dissuade acceleration behaviour during the execution phase.
A Five Wang Year
This has been a 5 Wang Year for me. I have co-authored six papers with five different lead authors with the family name Wang, the most common surname in the world. I don’t know if this is a world record, but I figured it was worth calling out. I expect there will be further papers co-authored with Wangs, as three of my current students have that name (one who joined this year, and didn’t make the list):
Wang, Haotian, Moylan, E. and Levinson, D. (2022) Prediction of the Deviation between Alternative Routes and Actual Trajectories for Bicyclists. Findings, June. [doi].
Wang, Jiaoe, Huang, Jie, Yang, Haoran, and Levinson, D. (2022) Resilience and Recovery of Public Transport Use during COVID-19. npj Urban Sustainability 2(18) [doi]
Wang, Yadi and Levinson, D. (2022) Time savings vs Access-based Benefit Assessment of New York’s Second Avenue Subway. Journal of Benefit Cost Analysis. 13(1) 120 – 147. [doi]
Wang, Yadi and Levinson, David (2022) Forecast Accuracy of Recent Australian Passenger Rail Projects. Presented at Australasian Transport Research Forum.
Wang, Yingshuo, Lahoorpoor, B. and Levinson, D. (2022) The Spatio-temporal Evolution of Sydney’s Tram Network Using Network Econometrics. Geographical Analysis. [doi]
Wang, Yuning, Lu, D, and Levinson, D. (2022) Equilibrium or Imbalance? Rail Transit and Land Use Mix in Station Areas. Transportation. [doi]
Follow-Up: Embettering Benefit-Cost
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Australian Transport Assessment and Planning (ATAP) guidance published last year aimed at improving the process of considering BRT alongside LRT as options: 09 Bus Rapid Transit and Light Rail Transit Cost Benefit Analysis .
As a general comment, Australia’s ATAP guidance is far more systematic and thorough than anything that happens in the United States. If only it were determinative of selection.
In case you or other readers are interested, here are a few salient references of interest:
OECD’s International Transport Forum has had a series of workshops over the past few years on the limitations of CBA and need for broader perspectives. For example, see
It is widely recognized that the specific calculation technique referred to as CBA, due to its adoption of a discounted value monetization roll-up, cannot capture distributive, intergenerational and cumulative effects that would cover many social and environmental (public) benefits. To cover those benefit categories, the OECD workshops found that governments across the world are increasingly relying on what is referred to as business case, multiple account, or multi-criteria evaluations.
There have been some alternative efforts to extend the CBA framework to recognize public “willingness to pay” for additional public benefits not captured in classic CBA. One prominent example is the efforts of APTA (American Public Transportation Association) and AASHTO (the association of US state DOTs) to put forward the concept of a “Business Case ROI” that is supplemental to classic CBA. See the 3-volume guide to Business Case ROI for intercity rail at https://aashtojournal.org/2021/06/18/aashto-apta-issue-high-speed-rail-investment-guide/ There is a lingering debate about the efficacy of attempting to quantify such factors in an ROI, versus handling it in more qualitative terms.
Weisbrod, G., & Goldberg, J. (2022). Relationship of Regional, Freight, and Intermodal Market Access to Industry Location and Productivity. Transportation Research Record, 0(0). https://doi.org/10.1177/03611981221131306
Follow-Up: Enlightening Rail
I read with interest your latest comment about over-design of the Sydney LRT. I thought you would like this pic from the Brisbane City Council photo collection showing how they built light rail in 1904.
Out of interest. This is what the street looks like now.
Thanks - I found your light rail piece very interesting and thought-provoking.
I've also long-advocated for shifting toward 'programs' rather than individual projects. And trams in Melbourne or Sydney are a logical fit for that sort of thing.
I noted that on the one hand, your 'total tram transformation' package estimate for Sydney was extremely large. On the other hand, it's about what it costs. And other transport exercises in Australia have similar price tags.
For example - we've already surpassed a similar price tag here in Melbourne for … ‘grade separations’. Nobody wants to talk anymore about how much that has cost, nor the opportunity cost associated. Or we could say something similar about Sydney's motorways extravaganza, not least the price inflation involved in pushing so many of those projects more-or-less simultaneously.
Follow-Up: Why Sydney should [should not] build a tram network
Chat-GPT is a Large Language Model (LLM) developed by OpenAI.
I asked : Write a blogpost on why Sydney should build a tram network
The following is computer generated text.
The city of Sydney is one of the most vibrant and exciting places to live in Australia. It is also rapidly becoming one of the most congested cities in the world. With a population of over 5 million people and a growing demand for transportation, it is no wonder that Sydney is struggling to keep up with its own growth. One way to help alleviate some of the traffic burden is to build a tram network in Sydney. Here are some of the reasons why Sydney should build a tram network.
1. Improved Public Transportation: The most obvious benefit of a tram network in Sydney is that it would improve public transportation options. Trams are a much more efficient and cost-effective way to get around than cars or buses. They are also quieter and less intrusive than cars, making them an ideal choice for those who want to get around the city without adding to the traffic congestion.
2. Increased Mobility: A tram network would also increase the mobility of those living in Sydney, especially those who are disabled or elderly. Trams are much more accessible than other modes of public transportation and can make it easier for those who are not able to use cars or buses to get around the city.
3. Better Quality of Life: Trams can also contribute to a better quality of life in Sydney. The addition of a tram network would make it easier for people to access jobs, shops, and other amenities that are located in different parts of the city. This would make life more convenient for everyone and could help reduce air pollution and traffic congestion.
4. Economic Benefits: Building a tram network in Sydney would also bring economic benefits to the city. The construction of the network would create jobs, and the increased transportation options would make it easier for people to access businesses and services located in different parts of the city. This would lead to an increase in economic activity and boost the local economy.
Sydney is an amazing city with a lot of potential. A tram network could help unlock this potential and make the city even more vibrant and attractive to both locals and visitors alike. With increased public transportation options, increased mobility, better quality of life, and economic benefits, building a tram network in Sydney is definitely something worth considering.
I then asked: Write a blogpost on why Sydney should not build a tram network
Sydney is one of the most iconic cities in the world and it is a popular destination for tourists and locals alike. However, the city is facing a number of challenges that need to be addressed before it can truly become one of the world’s great cities. One such challenge is the question of whether or not Sydney should build a tram network.
The idea of a tram network in Sydney has been floated for many years, but there are a number of compelling reasons why it should not be built.
Firstly, trams are expensive to construct and maintain. Sydney already has a comprehensive public transport network which is served by buses, trains, and ferries. Building a new tram network would require a significant investment of both money and time, and the cost could be better spent on improving existing infrastructure or providing other public services.
Secondly, Sydney is already a congested city and the addition of trams would only add to the problem. Trams require a dedicated track, which would mean sacrificing valuable road space for their construction. This could have a significant impact on traffic flow and could make travelling around the city even more difficult than it already is.
Finally, trams are not particularly efficient. They are slower than buses and trains and can cause more disruption when they are delayed or stopped due to mechanical issues. This could lead to significant delays for passengers and could worsen the city’s already poor public transport reliability.
For all of these reasons, it is clear that Sydney should not build a tram network. The city has enough on its plate without the added expense and disruption that a tram network would bring. Instead, the focus should be on improving existing infrastructure and services, to ensure that Sydney remains one of the world’s great cities.
You decide, the AI doesn’t care. Grading essays next year will be fun.
I sometimes poll my social (Twitter/Mastodon) followers. This from last month:
When using a ride-sourcing service like Uber or Lyft or Didi etc, do you only check one provider, or do you usually price (or time) compare between services before choosing?
Check only one service 42.9% / 74%
Check multiple services 57.1% / 26%
Sample size 49/19
So on average around 50% each, averaging the two pools. I don’t know if Twitter users are more price- or time-sensitive, or this is just randomness in the data.
I conclude the pricing power of the duopolist is somewhat limited by consumers shopping around. I do see high price variations from time-to-time, but so do the drivers. When Didi (a distant second in the Sydney market) is much lower than Uber, it means I usually cannot actually get a Didi.
“When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put the ways of childhood behind me.” - 1 Corinthians 13:11
When I was young, I lived in US (+1 international dialing code) area code 301 (though since that time, the area code has been rent asunder, and the areas I grew up in are now in the 410). In those earlier halcyon days, in the era before the internet, whenever I was in a hotel or visiting a relative in a new city, I would look at the front of the white pages and the yellow pages to help me understand how the city (and phone system) worked.
At the beginning of the phone book was a map of area codes, the North American Numbering Plan. AT&T, the only phone company that mattered at the time, assigned area codes in 1947 to allow direct long distance dialing.
Recent years have seen the popularity of area codes as short-hand for the cities they represent. E.g. the 404 for Atlanta or the 212 for New York. (North American area codes historically had a 0 or 1 in the second digit, to differentiate them from local numbers for the early electro-mechanical switches, but that restriction was relaxed to expand the number of numbers, lest the digits run out.) Today the hip name for the District, Maryland, and Virginia is the DMV, probably as a joke on the Department of Motor Vehicles, which in Maryland is the MVA, though DC and Virginia call it DMV.
Australia similarly has area codes for each state for land lines, but they are only a single digit. New South Wales and Canberra (ACT) are 02, Victoria and Tasmania are 03, 07 for Queensland, 08 for South Australia, Northern Territories, and Western Australia. Locally 027, 028, or 029 indicate Sydney. Yet mobile numbers don’t have location information, and instead all begin with 04. Further digits are allocated to different carriers. (Though there is phone number portability).
Australia, like all countries I suppose, does have an international dialing code. I thus live in the +61. The Plus Six One. It sounds fashionable. It has three syllables. Someone should promote this.
Causality Podcast 45: Granville - About Sydney Granville Rail Disaster
Seize the Elevators - Public elevators (and skyways) for a truly 3-dimensional city.
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