The dominant method for measuring values of travel time savings (VOT) and values of travel time reliability (VOR) is discrete choice modeling. Studies using revealed preference have tended to use travel times measured by devices such as loop detectors, and thus the perception error of travelers has been largely ignored. In this study, the influence of commuters’ perception error is investigated on data collected of commuters recruited from previous research. The subjects’ self-reported travel times from surveys, and the subjects’ travel times measured by GPS devices were collected. The results indicate that the subjects reliability ratio is greater than 1 in the models with self- reported travel times. In contrast, subjects reliability ratio is smaller than 1 in the models with travel times as measured by GPS devices.
Once upon a time (1888 to be precise), the United States and the world launched a huge building boom for urban streetcars. Companies like Twin City Rapid Transit laid miles of track in fast-growing cities, extending well past the built areas to serve greenfield sites for emerging suburbs waiting to be platted and built. They did this because the streetcar promoters benefited directly from the land sales. The availability of a new, fast transit system connecting to downtown made houses much more valuable. The fares from the new passengers covered the operating costs of the system.
What is the optimal size of a research paper? The answer, of course, is that it depends. Some research findings are complex and difficult to explain, and are highly intertwined. Others are much more straight-forward, using well-understood methods to observe something new. However, most papers in most journals are expected to be of a certain length. In transport journals, for instance, this length is typically 3500 – 8000 words. This leaves a lot of words to fill, and people often stuff them, or are asked to stuff them, with repetition of well-known and well-established theory, regurgitation of self-explanatory tables and figures, citation of tangentially related research, and other matters describing what was not done in the research. Without a tight word count restriction, the authors have no recourse but to include filler at the bequest of the almighty reviewers, or in anticipation of such bequest.
Transport Findings takes the opposite approach. With a 1000 word cap (plus a maximum of 3 figures and 3 tables), it demands authors get to the core of their results: what did they measure, how did they measure it.
It’s really surprising what you can say in a few words. The Gettysburg Address was 270 words, depending on version.
Some people think fewer words means less work. The opposite is often true. Omitting needless words requires editing, and good editing takes time. The amount of time spent typing is not anywhere close to the amount spent reviewing, revising, and redacting in a brief text. We do that not for ourselves, but for our readers, to save them time, to help them see the point clearly without having to wade through a morass of miscellany and nonsense.
There are other reasons for short papers in addition to the benefits for the reader. They are faster to review, and so can go from conception to publication in less time than it takes some journals to move an article from their inbox to the review queue. I’d hypothesize (without any actual data, but impressionistically) that review time increases with the square of article length. So a 4000 word article will take reviewers on average 16 times longer to be reviewed than 1000 word article, neglecting fixed costs of getting people to read their email. Several things factor into this, most obviously considering the interactions of words in a text (a 4000 word article has far more textual interactions than a 1000 word article), but also including dread at reading a long rather than a short document for precisely that reason. And words beget words, a long document citing everyone but me can easily be just a bit longer.
We are now able in the academic community to produce many different kinds of research outputs, ranging from raw data, to figures and charts, to regression analyses, to texts and papers. These can all be put online at data conservancies and given permanent identifiers. Peer review still has some cache as a quality filter, let’s not waste the scarce time of volunteer reviewers with noise.
Spatial weight matrix is unstable over time-of-day, while network weight matrix is robust.
Performance of network weight matrix in non-rush hour is better than rush hour.
The best look-back time window depends on the travel time between two study detectors.
The best look-back time window is shorter in uncongested than congested regimes.
This study examines the spatiotemporal dependency between traffic links. We model the traffic flow of 140 traffic links in a sub-network of the Minneapolis-St. Paul highway system for both rush hour and non-rush hour time intervals, and validate the extracted network weight matrix. The results of the modeling indicate: (1) the spatial weight matrix is unstable over time-of-day, while the network weight matrix is robust in all cases and (2) the performance of the network weight matrix in non-rush hour traffic regimes is significantly better than rush hour traffic regimes. The results of the validation show the network weight matrix outperforms the traditional way of capturing spatial dependency between traffic links. Averaging over all traffic links and time, this superiority is about 13.2% in rush hour and 15.3% in non-rush hour, when only the first-order neighboring links are embedded in modeling. In addition, this study proposes a two-step algorithm to search and identify the best look-back time window for upstream links. We indicate the best look-back time window depends on the travel time between two study detectors, and it varies by time-of-day and traffic link.
Train riders have to get to stations somehow. This is often referred to as the “first mile” or “last mile” problem. There are many technical solutions to help travellers get from home to the station and back, ranging from cars to electronic scooters, but most people use a much older technology, their feet, to get from A to B. What is seldom considered is access to the train platform itself.
Stations are not points but places. They occupy a large area. A person walking at average speed takes about two minutes to walk from one end of a full-length eight-car train to the other.
Often platforms have a single access point on one side of the station, which makes it more difficult for people on the other side of the station to get to the platform. Passengers may need to almost circumnavigate the station to get to the platform. At an average walking speed, the extra distance they must backtrack adds up to six minutes per trip each way, our research has found.
Imagine being so unlucky to have an extra 12 minutes of travel time every day if you take the train. You might be tempted to drive instead.
The table below shows the extra travel time in minutes depending on platform locations and access points for a traveller’s origin and destination. The average time for such a one-sided configuration of train stations is 3.25 minutes each way.
Table 1: Additional Travel Time Depending on Origin and Destination Residence and Workplace Location vis-a-vis Platform Location.
While this example is hypothetical, it is drawn from experience in Sydney, where 44 of 178 train stations have only a single side entrance.
So what impact will a second entrance have?
We examined those stations and access to their platforms: how many people lived within 5, 10 and 15 minutes of the station platform, considering actual entrance location, and how many jobs were within 5, 10 and 15 minutes of the platform. Using existing ridership data from Opal cards, we estimated a model that related the passenger entry and exit flows at each station to that station’s accessibility.
We sketched a second entrance at those 44 stations and measured accessibility again. It’s now higher, as having two entrances instead of one means more people can reach the platform in the same time. We then estimated the increase in ridership from the model due to the improved accessibility, assuming no change in population or employment.
Over all 44 stations, total morning peak period entries increased by 5%. But some stations benefit a lot, and others not at all, so prioritisation of investments matters.
It will be no surprise to locals that Erskineville station comes out on top with a nearly 35% increase. While many of the new apartment-dwelling residents west of the station make the extra hike every day, even more would catch the train if there were a convenient entrance.
Other top 10 stations include: Bankstown, Newtown, Villawood, Redfern, Burwood, Sydneham, Caringbah, Meadowbank and Penshurst. Planning is already under way to improve Redfern station.
While this result considers existing development, adding a second entrance can make new transit-oriented development that much more valuable. This is because it will likely increase activity on the previously less accessible side of the station, as the example of Erskineville shows below.
Other considerations include accessibility for people who cannot use staircases, as many of the stations are older and will require lifts. The prospects of park-and-ride lots, the costs of construction, the presence of nearby stations, and site feasibility also play into final decisions.
Welcome to the May 2019 issue of The Transportist, especially to our new readers. We are testing a new newsletter platform, Substack. If you received this by email, you have been migrated, and no action is required on your part. As always you can follow along at the transportist.org or on Twitter.
Like Newton in Mechanics or Tobler in Geography, we ought to have laws in transport. I posit the following:
Law 1: Everyone complains about transport, independent of the quality of travel experienced.
The stated argument for criminalising “jaywalking” (not an actual crime, but rather a slander on people crossing spaces that used to be free to cross) is that in an environment where automobile drivers only pay attention to lightbulbs, rather than the environment around them, people would be at risk for crossing against said lightbulbs. And so to prevent such risk, jaywalking must be made illegal. While actual pedestrians are the first to recognise that drivers pay less attention to the world around them than they should, this is not despite lightbulbs, it is because of them. The traffic signs, signals, and markings are themselves a distraction from human-to-human interaction, the eyelock we engage in before crossing paths in humane environments.
Should government subsidize transport? If government subsidizes transport, should it subsidize producers or consumers? If a government gave money to consumers, they could spend it on what they want, paying for a service, which if it covers operating costs, could lead to more investment. If it gave money directly to producers, they spend it on more supply. Which leads to a better outcome?
I am honoured to report that I have been invited to give the 12th Annual Martin Wachs Distinguished Lecture in Transportation, Thursday, May 16, at the UCLA Campus. Registration via Eventbrite.
Reception in honor of David Levinson 5:00pm – 6:00pm UCLA Public Affairs, 3rd Floor Patio
Wachs Distinguished Lecture with David Levinson 6:00pm – 7:30pm UCLA Public Affairs, Room 2355
The 30-minute isochrone has long defined people’s use of cities — from ancient times through the trams era to modern times. Networks and land use co-evolve with technology subject to the constraints of available time. There are opportunities (low-hanging fruit) to use design to reduce the costs of travel and thus increase access for relatively little monetary outlay. This talk discusses both the measurement of accessibility, why it matters, and how it might affect traveler behavior, institutional behavior, and public policy. Looking at data from rail and tram development in Sydney from the 1800s and Australia today, implications about the effects of accessibility will be described.
David Levinson is professor in the School of Civil Engineering at the University of Sydney and adjunct faculty in the Department of Civil, Environmental, and Geo-Engineering at the University of Minnesota. Levinson received the 1995 Tiebout Prize in Regional Science for the paper “Location, Relocation, and the Journey to Work.” From 1989 to 1994, he worked as a transportation planner, developing integrated transportation and land-use models for Montgomery County, Maryland. He has a PhD in transportation engineering from Berkeley and his dissertation “On Whom the Toll Falls,” argued that local decision-making about managing and financing roads will most likely lead to direct road pricing, which will allow the efficient allocation of scarce road resources (and thus reduce congestion).
About the Wachs Lecture:
Now in its 12th year, the annual Martin Wachs Distinguished Lecture draws innovative thinkers to the University of California to address today’s most pressing issues in transportation. Created by students to honor Prof. Wachs upon his retirement from the university, the lecture rotates between Berkeley and UCLA, the campuses at which he taught.