"A long-time limit for world subway networks" recently published in the Journal of the Royal Society Interface investigates how subway systems in major urban areas develop over time. Written by Camille Roth, Soong Moon Kang, Michael Batty and Marc Barthelemy, the article compares the subway systems of major cities.  It looks at Barcelona, Beijing, London, Moscow, New York City, Seoul, and Tokyo, to find similarities of each system's development. The article was discussed by Scientific American, Wired, and the BBC.

This question is remiscent of another article which asks "Are motorways rational from slime mould's point of view?"

Tomorrow, Thursday May 17, there will be a special seminar. Ricardo A. Daziano of Cornell University will present, "Accounting for Uncertainty in Willingness to Pay for Environmental Benefits."

Previous literature on the distribution of willingness to pay has focused on its heterogeneity distribution without addressing the interval estimation problem.  In this paper we derive and analyze Bayesian confidence sets for quantifying uncertainty in the determination of willingness to pay for carbon dioxide abatement. We use two empirical case studies: household decisions of energy-efficient heating versus insulation, and purchase decisions of ultra-low-emission vehicles. We first show that deriving credible sets using the posterior distribution of the willingness to pay is straightforward in the case of deterministic consumer heterogeneity. However, when using individual estimates, which is the case for the random parameters of the mixed logit model, it is complex to define the distribution of interest for the interval estimation problem. This latter problem is actually more involved than determining the moments of the heterogeneity distribution of the willingness to pay using frequentist econometrics. A solution that we propose is to derive and then summarize the distribution of the point estimates of the individual willingness to pay.

The seminar will be in 212 O'Brien Hall from 2-3 PM.

This year's Research in Transportation Economics focuses on Transport Development in China. The articles examine issues such as the impact of highspeed rail on aviation, port competiveness, and the liabilities of multimodal operators.

Yesterday the move of a portion of our collection to the Annex was completed. The material in the Annex is still accessible by request. High-use material, such as every thing from the Transportation Research Board is available in the library. We are working to update our records in the catalog, so if you need help finding anything don't hesitate to ask.

We've also moved furniture around in preparation for construction this summer. Hopefully that will take place next month, but the date has yet to be finalized. We will let you know as soon as it's scheduled.

Summer Hours will start next week. We'll be open Tuesday through Friday from 1-5 p.m.

The Library will be closed this Tuesday and Wendesday (May 8 and 9) while part of our collection is moved to our new Annex. This is the start of a number changes for the library over the next few months. We'll reopen Thursday with normal hours. If you have any questions or need immediate asistance, email itslib@berkeley.edu.

Thanks for your patience.

This week's Friday TRANSOC Seminar features Celeste Chavis, Ph.D. candidate, University of California, Berkeley, presenting "Analyzing the Structure of Informal Transit Systems."

Through the use of a profit-maximizing continuum approximation model, this presentation systematically analyzes the development and structure of informal transit systems as a function of the network, user, and modal characteristics.  The study examines the evening commute problem along a linear corridor where passengers with a constant trip generation rate at the CBD travel to destinations uniformly distributed along the corridor.  Informal transit drivers who are profit-maximizing will be compared against the traditional case of coordinated, government service that aims to maximize the total welfare. Policies, such as fare regulation and vehicle licensing schemes, will be presented to help rationalize informal transit service using a government-operated service as the baseline.

The seminar will be held in 534 Davis Hall on Friday, May 4, from 4:00-5:00pm. Please join us for a TRANSOC-sponsored Cookie Hour in the ITS Library, 412 McLaughlin Hall, at 3:30pm.

This week's Friday TRANSOC Seminar features Robert Campbell, Ph.D. candidate, University of California, Berkeley, presenting "Failure to Yield: A Framework for Evaluation of Compliance Measures."

In this presentation, we explore the safety problem of drivers violating yield signs in a freeway context. Drivers violating traffic controls is a common problem, and agencies have a collection of strategies that they often use to address the problem. These include increasing the size of the traffic control, adding an advanced warning upstream, installing pavement markings, or using LEDs to capture drivers' attention. As common as these (and other) compliance measures are, however, no research has been done to properly evaluate how they compare in terms of effectiveness.

In cooperation with Caltrans, two different compliance strategies—increasing the size of the control, and adding supplemental pavement markings—were implemented on Interstate 10 in Los Angeles so that the effectiveness of each could be measured in the field. Although our experiments involve yield sign violations, the insights obtained can be adapted to other contexts as well, such as pedestrian crosswalks or turn prohibitions at intersections.

We will explore the outcomes of these two experiments and, using a method we have developed to allow for responsible comparisons of effectiveness, will come to conclusions about the performance of each one. Our analysis offers insights into the mechanisms behind the observed behavioral response that occurs in drivers over time after a strategy is implemented (including what happens in the often-ignored "unstable" or "novelty" phase), which we can then use to inform our assessments of each compliance strategy. Our results will reveal flaws with the conventional before-and-after approach used to evaluate compliance measures, and will show how such errors can be avoided or corrected.

 The seminar will be held in 534 Davis Hall from 4:00-5:00 on Friday, April 27. Please join us for a TRANSOC-sponsored Cookie Hour in the ITS Library, 412 McLaughlin, from 3:30-4:00.

This week's Friday TRANSOC Seminar features Karthik Sivakumaran, Ph.D. candidate, University of California, Berkeley, presenting "Access and the Choice of Transit Technology."

An urban transit system can be made more efficient by improving the access to it.  Efforts in this vein often entail the provision of greater mobility, as when high-speed feeder buses are used to carry commuters to and from trunk-line stations.  Other efforts have focused on the creation of more favorable land-use patterns, as occurs when households within a Transit-Oriented Development (TOD) are tightly clustered around trunk stations.  The efficacy of these mobility and land-use solutions are separately examined in the present work.  To this end, continuum approximation models are used to determine the design parameters that minimize the generalized costs to both the users and the operators of hypothetical transit networks.

Though idealized, these assessments furnish useful and very general insights.  They confirm that if transit is accessed slowly on foot, as is commonly assumed in the literature, then the optimal spacings between routes, and between the stations along those routes, are quite small.  This typically places capital-intensive rail systems at a competitive disadvantage with transit systems that feature buses instead.  However, these spacings expand when access speeds increase.  Hence, we show how Bus Rapid Transit (BRT) and Metro-Rail can become a preferred option for trunk-line service when accessed via faster-moving feeder buses.

By comparison, the influence of altered land use patterns brought by TODs is less dramatic when all users walk to Metro-rail stations.  We find that clustering households around these stations justifies larger spacings between them, but produces only modest reductions in generalized costs.  This is because the larger spacings penalize transit users who reside outside of the TODs.

The seminar will be held at 4:00pm in 534 Davis Hall. Don't forget about Cookie Hour in the library at 3:30! See you here.

This week's TRANSOC Friday Seminar features Anurag Pande presenting, "Traffic crash patterns: What can we learn from retailers?"

 Data mining applications are becoming increasingly popular for many applications across a set of very divergent fields. Analysis of crash data is no exception. Association analysis or market basket analysis is used by retailers all over the world to determine which items are purchased together by consumers. It is then applied to stock items (e.g., Salsa and Chips) close to each other. In traffic safety research based on association rule mining, crashes are analyzed as supermarket transactions to detect interdependence among crash characteristics. The results from the analysis include simple rules that indicate which crash characteristics are associated with each other. Results will be presented from two of research articles in which this application is demonstrated using crash data from the state of Florida.

The seminar will be at 4:00pm in 534 Davis Hall as usual. Don't miss Cookie Hour in the library at 3:30!

This week BRTdata.org was launched by the Bus Rapid Transit Center of Excellence and EMBARQ. The site acts a clearinghouse for data from BRT systems all over the world. You can see performance indicators by country or city, such as passengers per day, number of corridors, and legth. Check it out and let them know what you think.