Transportist: July 2022

News or Opinion: You Decide

  • Why the return to the office isn’t working — This is a fundamental problem, especially between organisations. When in the office I am Zooming with people across the hall because the third person isn’t showing up. Students in Sydney are attending the Zoom version of Hybrid/Flexible (Hyflex) classes rather than attending in person as they are supposed to. This is a problem for teaching in that many good in-person class activities don’t work if critical mass is not attained. The stable Nash equilibrium without a mandate/subsidy for going to the office or school is that nearly everyone works or studies from home. This is reinforced by our general acceptance of covid and flu as a normal part of life, (rather than trying for elimination), but with “the out” that no one mustphysically attend anything, so it becomes the universal excuse for WFH (available both to people with and without illness, as no one can prove anything).

Twitter avatar for @I_Am_NickBloomNick Bloom @I_Am_NickBloom Returning all WFH employees to the office 5-days-a week looks almost impossible – Firms pushing 5 day returns see <50% compliance – Firms pushing 4 days or less see >80% compliance Firms should aim for something moderate and succeed, rather than aim for a 5-day return and fail

Image

June 8th 2022 61 Retweets 146 Likes

Prezos

In Australian English, perfectly functional, but needlessly long words are often shortened or replaced. A mail carrier is a postie, an electrician is a sparky, trash collectors are garbos, the relatives are relos, and so on. I am not clear on the rule about why a particular shortened word takes the “-ie” (or -”y”) or “-o” ending. A presentation is a prezo. (Arguably it might be a prezzie, but that is a piece of software. The zed might be an s.) The following are some upcoming prezos. heroJuly 2 I will be at an online Public forumTraffic signals and how small improvements can make walking a whole lot faster and better.ABOUT: Prof David Levinson, founding president of WalkSydney and Professor of Transport Engineering at the University of Sydney gives a fascinating speech about traffic signals. In Sydney, traffic signals give priority to motor vehicles over pedestrians. This inequality undermines many of the stated goals of transport, health, and environmental policy.

  • DATE: Saturday 2 July 2022 11:00 AM – 11:45 AM (UTC+10)
  • LOCATION: Online event access details will be provided by the event organiser to registered participants.

July 5 and 6 I will be giving virtual guest lectures at Southwest Jiaotong University in Chengdu.

July 7 I will be presenting in person at the UDIA NSW Young Leaders Committee.

July 22 I will be presenting in person at the AITPM National Conference in the session: Planning for future-focused cities using a variety of data and modelling techniques

Sept 14 I will be presenting in person at: Reducing Australia’s Transport Emissions, Sydney 14th September 2022Exploring evidence based solutions to reduce Australia’s fastest growing source of emissions

Maybe I will see you there.

Research

  • Wang, Haotian, Emily Moylan, and David M. Levinson. 2022. “Prediction of the Deviation between Alternative Routes and Actual Trajectories for Bicyclists.” Findings, June. https://doi.org/10.32866/001c.35701.

ABSTRACT: This study estimates a panel regression model to predict bicyclist route choice. Using GPS trajectories of 600 trips from 49 participants in spring 2006 in Minneapolis, we calculate deviation, the average distance between alternative routes and actual trajectories, as the dependent variable. Trip attributes, including trip length, Vehicle Kilometres Travelled (VKT), the number of traffic lights per kilometer, and the percentage of bike trails and separated bike lane, are included as independent variables. F-tests indicate that both fixed entity and time effect panel regression models offer better fits that the intercept only model. According to our results, routes with shorter length and higher share of bike trails tend to have less deviation in their trajectories. Traffic lights per km, VKT, and share of bike lane are not significant at 95% confidence level in this data set.

  • Loyola Borja, Miguel, Nelson, J., Clifton, G., and Levinson, D. (2022) The relation of visual perception of speed limits and the implementation of cycle lanes – a cross-country comparison. Accident Analysis and Prevention. Volume 174, September 2022, 106722. [doi]

ABSTRACT: Speed plays a key role in road safety research. Recent studies have indicated an association between speed limits and driving behaviour. However, less attention has been paid to the role of context in the perception of speed limits, and the way cycle lanes influence this perception. This study examines how respondents in different countries of residence perceive speed limits, and how cycle lanes influence their perception of speed limits. An online survey provided quantitative data for a cross-country comparison from 1591 respondents in Australia, the Netherlands, and the United Kingdom. The findings show that country of residence influences the way speed limits are perceived, and cycle lanes are interpreted distinctly. In locations where cycle lanes are common, they act as indicators of either lower or higher speed limits, while in countries with less familiarity with cycle lanes respondents associate cycle lanes only with lower speed limits. Suggesting a safer and broader understanding of cycle lanes where they are familiar (the Netherlands) and a narrower understanding where cycle lanes are not common (Australia and the United Kingdom), this study provides evidence for policymakers explaining resistance to implementing cycle lanes and implies that implementing lower speed limits and cycle lanes are a road safety measure. Suggestions are identified for future research.

Research by Others

Follow-Up

GW Writes:

I continue to enjoy reading your newsletter, which has some great insights. I liked your recent article on tradeoffs (“Towards Zero”). However, I thought you might be interested to know that in this particular case your terminology use — equating CBA with “business case” (highlighted below) — is different from the UK and US uses of the business case concept.The UK’s transport appraisal guidance on business case analysis positions it as something separate from CBA — as a qualitative process to cover broader, strategic considerations beyond what is covered in CBA (covering things like equity, distribution and place-based impacts).  And recent work in the US by APTA and AASHTO committees has extended the UK view of business case to quantitative analysis, by defining a concept of “business case ROI” that monetizes the broader strategic business case factors using implied willingness to pay. I think you might be interested to read about the latter (as I worked on it). Here are two links to it. 
New High-Performance Rail ROI Report – American Public Transportation AssociationAASHTO, APTA Issue High Speed Rail Investment Guide – AASHTO Journal

More on Sydney Trains.

Prediction of the Deviation between Alternative Routes and Actual Trajectories for Bicyclists

Recently published:

  • Wang, Haotian, Emily Moylan, and David M. Levinson (2022) “Prediction of the Deviation between Alternative Routes and Actual Trajectories for Bicyclists.” Findings, June. [doi].

This study estimates a panel regression model to predict bicyclist route choice. Using GPS trajectories of 600 trips from 49 participants in spring 2006 in Minneapolis, we calculate deviation, the average distance between alternative routes and actual trajectories, as the dependent variable. Trip attributes, including trip length, Vehicle Kilometres Travelled (VKT), the number of traffic lights per kilometer, and the percentage of bike trails and separated bike lane, are included as independent variables. F-tests indicate that both fixed entity and time effect panel regression models offer better fits than the intercept-only model. According to our results, routes with shorter length and higher share of bike trails tend to have less deviation in their trajectories. Traffic lights per km, VKT, and share of bike lane are not significant at the 95% confidence level in this data set.

Figure 1. Example of Commute and Non-Commute Trips

The relation of visual perception of speed limits and the implementation of cycle lanes – a cross-country comparison

Recently published:

  • Loyola Borja, Miguel, Nelson, J., Clifton, G., and Levinson, D. (2022) The relation of visual perception of speed limits and the implementation of cycle lanes – a cross-country comparison. Accident Analysis and Prevention. Volume 174, September 2022, 106722. [doi]

ABSTRACT: Speed plays a key role in road safety research. Recent studies have indicated an association between speed limits and driving behaviour. However, less attention has been paid to the role of context in the perception of speed limits, and the way cycle lanes influence this perception. This study examines how respondents in different countries of residence perceive speed limits, and how cycle lanes influence their perception of speed limits. An online survey provided quantitative data for a cross-country comparison from 1591 respondents in Australia, the Netherlands, and the United Kingdom. The findings show that country of residence influences the way speed limits are perceived, and cycle lanes are interpreted distinctly. In locations where cycle lanes are common, they act as indicators of either lower or higher speed limits, while in countries with less familiarity with cycle lanes respondents associate cycle lanes only with lower speed limits. Suggesting a safer and broader understanding of cycle lanes where they are familiar (the Netherlands) and a narrower understanding where cycle lanes are not common (Australia and the United Kingdom), this study provides evidence for policymakers explaining resistance to implementing cycle lanes and implies that implementing lower speed limits and cycle lanes are a road safety measure. Suggestions are identified for future research.

Fig. 1. Images before and after implementing cycle lanes, looking at the opposite side of the street (SOURCE: adapted from Google maps).

Transportist: June 2022

Congratulations to Australia for a peaceful transfer of power and the lack of demagogues proclaiming “election fraud”. 

Towards Zero

Life is full of trade-offs.

When we conduct a business case (benefit/cost analysis), “ideally” we reduce decision making to a comparison of the monetised benefits and monetised costs. We say, e.g., the value of travel time savings is 40% of the average wage rate. If there are any safety impacts, we might note that a  value of a statistical life is $11,800,000 (for Americans, it is much less in other countries, despite the US’s penchant for devaluing life). If we are doing a better than average job, and considering environmental externalities, we price pollutants, and may even have a carbon tax. We say all this as if life or environmental damage can be substituted by money. When designing a transport system, we may choose to invest in one safety feature and not another, and instead spend the funds on something that reduces travel time. 

Of course, we don’t say your life can be substituted by money, your life is priceless (to you), but other people’s statistical lives are not, and as humans, we don’t act as if they are. But following through to its “logical” conclusion, if we assume the average price holds even as the number of people decreases, the lives of some 8,000,000,000 people on planet earth could be traded for (society would be willing to accept) $9.44e+16 in exchange, but who would be there to receive it? So while the average statistical value of (other people’s) life perhaps holds at the margin, it cannot hold for the whole.

We have similar values for pollutants, but clearly a sufficient amount of some pollutants (CO, NOx, SOx, Pb, PM10, PM2.5, O3, CO2) would kill us all. So while the trade-off price might be valid at the margin, it must increase to infinity as the amount of pollution increases. 

In the end, human life is a perfect complement to human transport. More humans begets more travel. If there were no life, there would be no human transport, and vice versa. These are consumed together. And if this is clearly true in the end for everyone, it is probably true at the margins as well. So perhaps we should not be monetising life and the damages caused by pollution, but instead looking at reducing crash risk and pollution in an absolute sense. But even if we took a Pareto Optimisation approach (no one is worse off, or in this case, no externality is exacerbated), there would still be trade-offs, we could still make more safety improvements or more travel time reductions.

Treating externalities in a non-monetary way requires multi-criteria decision-making. But typically that only abstracts the problem away from money, there is implicitly still a trade-off. 

Over the short-run, this trade-off might be necessary, when so much of the system design is fixed; but does it remain over the long run? A system that pollutes is wasting resources. A system that kills people is wasting resources. That can’t be efficient overall, we are just shifting the burden from a subsystem of all life to another subsystem. 

We often treat life and health and the environment as sacred values. We embue lost lives, and polluted environments with emotion and meaning. In contrast, we don’t treat lost time as sacred. If one were to posit “Zero Delay” in the same breath as Zero Deaths, one would be viewed as a crank. Instead, to those stuck in traffic we say you wasted time, ha-ha, we are not saddened by the thought of others in congestion. 

Nevertheless, unlike road deaths and air pollution, delay continues to remain a salient political issue, which we see in the sloganeering of “congestion busting”, and implicit in all traffic engineering decisions aiming for a better Level of Service. I would also argue that delay is largely unnecessary1

I posit that it is less expensive in the long run to design a transport system that doesn’t pollute, and doesn’t kill, injure, and maim people, and doesn’t result in needless delays, than one that does. A long-run, over-arching benefit-cost analysis would recognise and reward better long-run designs that resulted in zero externalities, following on the ideas of “Net Zero” and “Toward Zero Deaths” from transport, rather than expecting trade-offs of time for safety or time for emissions.

New Journal: Urban Informatics

Urban Informatics (UI) is an international, open-access, peer-reviewed journal publishing high-quality, original research on urban informatics, including urban system, theories, methods, and technologies for urban big data acquisition, infrastructure and analytics, as well as new solutions to urban problems and applications. 

Though published by Springer/Nature, the Article Processing Charges are waived for the first two years.

I am on the Editorial Advisory Board.

Research

  • Zhao, X., Cui, M., & Levinson, D. (2022). Exploring temporal variability in travel patterns on public transit using big smart card data. Environment and Planning B: Urban Analytics and City Sciencehttps://doi.org/10.1177/23998083221089662 [doi]

News

Dysfunctions

AI

Pricing

Infrastructure

Electrification

Security

Futures Past

Image

1

Recognising that journey delay (time wasted in-vehicle driving at speeds below “freeflow”) would have to be replaced by schedule delay (time spent at the trip origin waiting to travel later, or departing early than desired to avoid journey delay, and thus spending time at the destination you would prefer not to). We assume journey delay is worse than schedule delay because you have more flexibility at your origin and destination to pursue other activities than when sitting in traffic or on a train. This despite time being a fraction of life, and certainly we would rather typically be doing something else.

Exploring temporal variability in travel patterns on public transit using big smart card data

Recently published:

  • Zhao, X., Cui, M., & Levinson, D. (2022). Exploring temporal variability in travel patterns on public transit using big smart card data. Environment and Planning B: Urban Analytics and City Sciencehttps://doi.org/10.1177/23998083221089662 [doi]

Abstract

Passengers generate travel behaviours on public transit, whose variations deserve an exploration with an aim to guide daily-updated managements. In this study, we investigate temporal variability in travel patterns for over 3.3 million passengers across 120 days who use public transit in Beijing. Temporal variability is characterized by a series of features in terms of space coverage, travel distance and travel frequency, based on which, passengers are clustered into two types, that is, commuters with daily travel routines, and non-commuters who do not. How, and to which extent, they change travel patterns over time are examined, with using approaches concerning multivariate regression and curve fitting. Results show that, (1) commuters are more likely to travel longer but cover less territory than non-commuters on weekdays, while the opposite patterns occur on weekends. The variation of day of week affects commuters less, compared to non-commuters, due to more fixed schedules, as expected; (2) travel distance and frequency are found to increase faster, more linearly, than space-coverage features, the last of which experience a progressive decreasing of marginal increases before reaching a plateau. The above findings facilitate transport practitioners to design sound management schemes for passengers in different categories.

Transportist: May 2022

Welcome to the latest issue of The Transportist, especially to our new readers. As always you can follow along at the  transportist.org or on Twitter.

PhD Students

I’m recruiting PhD students in Transport at the University of Sydney. Get in touch if interested.

Five Years Car Free

I have celebrated this past month my fifth year in Sydney and thus five years without a car.1 As Stephen Colbert might have said “I am carless, (and so can you!)”

This is not to say everyone in Greater Sydney could be carless, just a large fraction of the people. About 22% of the population lives within a 15 minute walk of a rail station, while 43% works within 15 minutes of a station. The number within walking distance of a bus is much higher, or 15 minutes by bus to rail.

Presently, by strategy not luck, I live 11 minutes downhill in one direction and 13 minutes downhill in the other direction to rail stations on different lines, only the second of which goes to Redfern which is 8 minutes from my office. So I have a 21-minute walk and 13-minute ride, if I time it perfectly without waiting time. To be clear, if I wanted to and didn’t have other family members to consider, I could optimise the arrival time, given the fairly high reliability of Sydney Trains in non-COVID, non-Industrial Action, non-Rainy times (which I guess is to say “cromulent” reliability given the circumstances, and better than similarly sized US transit systems would deliver). My previous commute in Minnesota was a 30-minute walk. My commute from my previous home in Alexandria was a 19-minute walk, circumnavigating Redfern station, but would have gotten shorter once the southern concourse opens.

That’s right, I am calling “BS” on many of the people who say they “need” their car. Cars are nice to have sometimes. Private cars are convenient and allow dynamically choosing destinations without planning or forethought. But cars themselves can be rented when they are needed. Taxis can be called when urban point-to-point transport off convenient public transport routes is required.

We can imagine a hierarchy of preferred modes:

  • Avoid the activity
  • Telecommute, work from home, etc.
  • Walk (or Cycle)
  • Delivery
  • Public Transport
  • Ride-sourcing
  • Car rental
  • Intercity Trains
  • Aviation

Now there are people, e.g. tradies who work at different sites every day and have equipment to carry with them, who would be much better off if everyone else didn’t drive and congest the roads, pollute the air, and endanger their lives.

In our five years without a car, we have used ride-sourcing (i.e. Uber, Didi, Bolt, etc.) multiple times, but probably no more than one round trip per week for the five-person household, so maybe $AU2000 per year tops, probably less with COVID. This is significantly less than the cost of car ownership.

We have rented cars on exactly 3 occasions in the past 5 years. 

  • Once shortly after arriving, for about 2 hours of GoGet, a car sharing service, to drive on the wrong side of the road. I disliked it, the lanes are narrow and drivers aggressive.
  • Second when my family arrived, to collect them and their stuff from the airport, and do a road trip to Brisbane for WSTLUR, while we were between housing.
  • Third for a road trip to Coonabarabran to see the stars in a Dark Skycommunity.

This is for a family of five, three of whom attend school, two work, thus none are in car seats or strollers.

No one in the family has really asked for more long car trips, though I am sure they would like to be driven to work or school on a rainy day (which seems like every day now in Sydney) or when they are carrying stuff because their school has implemented some stupid anti-COVID no locker policy (since retracted).

So do I not drive to save money, save the earth, save my sanity, be able to lord it over others? Who knows?

Conferences

Master of Transport

I will be talking about the University of Sydney’s interdisciplinary Master of Transportprogram at Post-Graduate Information Evenings on

  • Tuesday 10th May, 4.30pm to 7.30pm at MacLaurin Hall
  • Thursday 12th May, 6.30pm-7.30pm online, email for details.

Research

  • Wu, Hao, and Levinson, D. (2022) Ensemble Models of For-hire Vehicle Trips. Frontiers in Future Transportation. 3. [doi]
    • Ensemble forecasting is class of modeling approaches that combines different data sources, models of different types, with different assumptions, and/or pattern recognition methods. By comprehensively pooling information from multiple sources, analyzed with different techniques, ensemble models can be more accurate, and can better account for different sources of real-world uncertainties. The share of for-hire vehicle (FHV) trips increased rapidly in recent years. This paper applies ensemble models to predicting for-hire vehicle (FHV) trips in Chicago and New York City, showing that properly applied ensemble models can improve forecast accuracy beyond the best single model.
  • 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. (online first, open access) [doi]
    • Under the current practice of benefit-cost analysis, the direct economic benefits produced by a newly built transit facility are assessed based on how it affects travel time and various costs that are associated with transport needs and travel behavior. However, the time-saving-based benefit calculation approach has been questioned and criticized. Given the strong correlation between accessibility and land value, we propose the access-based land value benefit assessment as an alternative, and apply this assessment method to analyzing the Second Avenue Subway project in Manhattan, New York. The primary principle of the access-based method is that the economic value of a transport project’s intangible gains is largely capitalized by nearby properties’ value appreciation, which is directly caused by improved transport accessibility. We find that: (i) the actual travel time saving is lower than originally forecast; (ii) a strong positive correlation between residential property value and job accessibility by transit is observed; (iii) the appreciation in sold property value and rented property value both far exceed total project cost; and (iv) such results support the decision to approve and construct the Second Avenue Subway.
  • Rayaprolu, H., Wu, H., Lahoorpoor, B., and Levinson, D. (2022) Maximizing Access in Transit Network Design. Journal of Public Transportation. [doi]
    • This study adopts an Access-Oriented Design (AOD) framework for optimizing transit network design. We present and demonstrate a method to evaluate the best combination of local and express alternative transit system designs through the novel concept of ‘iso-access lines’. Two bus network system designs were explored for a greenfield development in suburban Sydney: through-routed transit lines (T-ways) with higher speeds and more direct service, but longer access and egress times, and local routes that provide additional spatial coverage. We developed scenarios with T-ways only, local routes only, and both, and computed transit access to jobs as a cumulative-opportunities measure for each scenario. Local routes offer greater overall access, while T-ways provide greater access-per-unit-cost. The optimal combination of the two was established by generating ‘iso-access’ lines and determining access-maximizing combinations for a given cost by applying production-theory principles. For 15-min access, the optimal combinations had T-way service frequency equivalent to 0.48 times that of local routes. This ratio increased to 1.45, 2.05 and 2.63 for 30-min, 45- min and 60-min access respectively. In practice, the method can be applied to determine optimal transit combinations for any given budget and desired access level.
  • Congratulations to Ang Ji for “satisfying the requirements for the award of the degree of Doctor of Philosophy at the University of Sydney.”
    • Thesis Title: Traffic programming: Aligning incentives for socially efficient lane changes among non-connected vehicles.
    • Lead Supervisor: Professor David Levinson.
    • Abstract: This dissertation explores the rationality of drivers’ risky and aggressive behaviors in lane-changing scenarios and discusses some feasible ways to hold selfish drivers accountable for their decisions. Regardless of potential congestion and crashes suffering by other road users, rational drivers prefer to maximize their gains and demand others’ yielding. However, when all of them have such thoughts, conflicts (dilemmas) are embedded in their interactions, leading to unexpected consequences for the whole traffic. This question is investigated analytically by exploiting the game theory concept. A simplified 2×2 non-cooperative game is built to model strategies executed by human drivers without communications. This research learns driver behavior in two predefined sub-phases: `Stay’ and `Execution’ from empirical data. This procedure examines the factors that impact drivers’ execution of lane changes. From the results, we understand that lane-changing is motivated by the urgency to change and the dissatisfaction with current circumstances. The analytical model is then established by integrating driver incentives into payoff functions. The `greed’ and `fear’ of drivers in this process are quantified by speed advantages and possible crash costs respectively, so they trade off these factors and make decisions based on their own and opponents’ estimated payoffs. Using a numerical case study, we find that social gaps exist between user-optimal and system-optimal strategies when drivers mostly engage in selfish behaviors, significantly deteriorating the total system benefit. Pricing can be a sufficient tool to incentivize users to cooperate with others and achieve win-win outcomes. It is posited that the designed pricing schemes may promote the negotiation between drivers, reducing collision risks and improving operational traffic efficiency. Several simulation experiments are then conducted to evaluate this dissertation’s hypotheses on the performance of pricing rules. Overall, the proposed framework develops a behavioral model and improvement schemes from the perspective of microscopic vehicular interactions. The conclusions will hopefully find their applications in autonomous vehicle-human interaction algorithms and future transportation systems.
    • Journal articles related to the dissertation include: 
    • Dr. Ji now has a position at Southwest Jiaotong University in Chengdu, one of China’s leading transport programmes.
    • The idea of Traffic Programming was first raised in this blog a while back (in 2016).
    • We recently were awarded a grant from the Australian Research Council to examine this question in further depth.
      • Design of micro-decisions in automated transport. Australian Research Council DP220100882 Professor David Levinson; Professor Michael Bell; Dr Mohsen Ramezani; Professor Dr Kay Axhausen; Professor Dr Hai Yang.

Research by Others

News and Opinion

Maximizing Access in Transit Network Design

Recently published:

  • Rayaprolu, H., Wu, H., Lahoorpoor, B., and Levinson, D. (2022) Maximizing Access in Transit Network Design. Journal of Public Transportation. 24 [doi]

This study adopts an Access-Oriented Design (AOD) framework for optimizing transit network design. We present and demonstrate a method to evaluate the best combination of local and express alternative transit system designs through the novel concept of ‘iso-access lines’. Two bus network system designs were explored for a greenfield development in suburban Sydney: through-routed transit lines (T-ways) with higher speeds and more direct service, but longer access and egress times, and local routes that provide additional spatial coverage. We developed scenarios with T-ways only, local routes only, and both, and computed transit access to jobs as a cumulative-opportunities measure for each scenario. Local routes offer greater overall access, while T-ways provide greater access-per-unit-cost. The optimal combination of the two was established by generating ‘iso-access’ lines and determining access-maximizing combinations for a given cost by applying production-theory principles. For 15-min access, the optimal combinations had T-way service frequency equivalent to 0.48 times that of local routes. This ratio increased to 1.45, 2.05 and 2.63 for 30-min, 45- min and 60-min access respectively. In practice, the method can be applied to determine optimal transit combinations for any given budget and desired access level.

Fig. 4. Schematic representation of transit connections designed for the development area. T-ways connect superblock centers with rail stations on either end. Local routes originate at rail stations, loop around superblocks and terminate at the origin stations.

Time Savings vs. Access-Based Benefit Assessment of New York’s Second Avenue Subway

Recently published:

  • 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]

Abstract

Under the current practice of benefit-cost analysis, the direct economic benefits produced by a newly built transit facility are assessed based on how it affects travel time and various costs that are associated with transport needs and travel behavior. However, the time-saving-based benefit calculation approach has been questioned and criticized. Given the strong correlation between accessibility and land value, we propose the access-based land value benefit assessment as an alternative, and apply this assessment method to analyzing the Second Avenue Subway project in Manhattan, New York. The primary principle of the access-based method is that the economic value of a transport project’s intangible gains is largely capitalized by nearby properties’ value appreciation, which is directly caused by improved transport accessibility. We find that: (i) the actual travel time saving is lower than originally forecast; (ii) a strong positive correlation between residential property value and job accessibility by transit is observed; (iii) the appreciation in sold property value and rented property value both far exceed total project cost; and (iv) such results support the decision to approve and construct the Second Avenue Subway.

Dr. Ang Ji

Congratulations to Ang Ji for “satisfying the requirements for the award of the degree of Doctor of Philosophy at the University of Sydney.”

Thesis Title: Traffic programming: Aligning incentives for socially efficient lane changes among non-connected vehicles.

Lead Supervisor: Professor David Levinson.

Abstract: This dissertation explores the rationality of drivers’ risky and aggressive behaviors in lane-changing scenarios and discusses some feasible ways to hold selfish drivers accountable for their decisions. Regardless of potential congestion and crashes suffering by other road users, rational drivers prefer to maximize their gains and demand others’ yielding. However, when all of them have such thoughts, conflicts (dilemmas) are embedded in their interactions, leading to unexpected consequences for the whole traffic. This question is investigated analytically by exploiting the game theory concept. A simplified 2×2 non-cooperative game is built to model strategies executed by human drivers without communications. This research learns driver behavior in two predefined sub-phases: `Stay’ and `Execution’ from empirical data. This procedure examines the factors that impact drivers’ execution of lane changes. From the results, we understand that lane-changing is motivated by the urgency to change and the dissatisfaction with current circumstances. The analytical model is then established by integrating driver incentives into payoff functions. The `greed’ and `fear’ of drivers in this process are quantified by speed advantages and possible crash costs respectively, so they trade off these factors and make decisions based on their own and opponents’ estimated payoffs. Using a numerical case study, we find that social gaps exist between user-optimal and system-optimal strategies when drivers mostly engage in selfish behaviors, significantly deteriorating the total system benefit. Pricing can be a sufficient tool to incentivize users to cooperate with others and achieve win-win outcomes. It is posited that the designed pricing schemes may promote the negotiation between drivers, reducing collision risks and improving operational traffic efficiency. Several simulation experiments are then conducted to evaluate this dissertation’s hypotheses on the performance of pricing rules. Overall, the proposed framework develops a behavioral model and improvement schemes from the perspective of microscopic vehicular interactions. The conclusions will hopefully find their applications in autonomous vehicle-human interaction algorithms and future transportation systems.

Ang Ji
Ang Ji

Journal articles related to the dissertation include: 

Dr. Ji now has a position at Southwest Jiaotong University in Chengdu, one of China’s leading transport programmes.

The idea of Traffic Programming was first raised in this blog a while back (in 2016).

We recently were awarded a grant from the Australian Research Council to examine this question in further depth.

  • Design of micro-decisions in automated transport. Australian Research Council DP220100882 Professor David Levinson; Professor Michael Bell; Dr Mohsen Ramezani; Professor Dr Kay Axhausen; Professor Dr Hai Yang.