Kendra K. Levine's blog

The State of Congestion: TTI releases the 2012 Urban Mobility Report

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Recently the Texas A&M Transportation Institute released the 2012 Urban Mobility Report. This year's model relies upon a new methodology and expands the coverage, and you can download the data for your city.   The changes give a better picture of issues related to traffic congestion across the United States, as well as historic trends from 1982 to present, though some question if TTI underestimates congestion back them. 

Unreliable Transit - Everybody hates it.

Two of the same bus bunched up

New research from ITS Berkeley found that inconsistent transit service was a major factor in people not using transit. From a paper presented at last week's TRB Annual Meeting by Andre Carrel, Anne Halvorsen and Joan Walker, riders' perception of transit reliability was examined. 

The most significant negative experiences that drove a reduction in transit use were delays perceived to be the fault of the transit agency, long waits at transfer points, and being prevented from boarding due to crowding. 

If you attended the meeting, you can download "Passengers' perception of behavioral adaptation to unreliability in public transportation". If you weren't able to attend TRB, we have it and the rest of the annual meeting papers available here at the library. 

(H/T NextCity and Governing.com)

The London Underground Turns 150

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On this date in 1863 London's Metropolitan Railway opened for business between Paddington and Farringdon stations, making it the world's first underground railway line and the most iconic. Celebrations have included 150 stories from passengers, looking back on its impact on culture, a journey along the historic Central Line, lots and lots of pictures, alternate tube maps, and the Google doodle

The Underground's impact on London and transportation in immeasurable. The growth of the city is linked to the growth of the Tube. Some consider it as a model for infrastructure management and investment. The history of the London Underground is as much a story of civil engineering as it is transportation planning and urban development. Perhaps its legacy is that it is still running and continues to evolve

Bay Area Traffic Decoded: What cell phone and GPS data reveals about traffic patterns

580 and I80 Traffic Jam

A new article from researchers at MIT and UC Berkeley uses data from cell phones and GPS to track traffic patterns. "Understanding Road Usage Patterns in Urban Areas" from December's Scientific Reports assess how drivers from certain areas effect the whole network. 

 We find that the major usage of each road segment can be traced to its own - surprisingly few - driver sources. Based on this finding we propose a network of road usage by defining a bipartite network framework, demonstrating that in contrast to traditional approaches, which define road importance solely by topological measures, the role of a road segment depends on both: its betweeness and its degree in the road usage network. Moreover, our ability to pinpoint the few driver sources contributing to the major traffic flow allows us to create a strategy that achieves a significant reduction of the travel time across the entire road system, compared to a benchmark approach.

Drivers from Sanjose, Hayward, Dublin, San Rafel and San Ramon often find themselves stuck in the worst traffic. Could more metering be the answer?

As car sharing goes mainstream, Avis buys Zipcar

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Yesterday it was annouced that rental giant Avis Budget Group bought car sharing upstart Zipcar. This is not the first car sharing acquisition by a rental company - Enterprise acquired Mint earlier in 2012. As car sharing gains popularity and a portion of the market share, it makes sense for rental agencies to get in on the action. Streetsblog speculates on what the implications of this deal may be, though some are already concerned about possible age discrimination. It's still early days, but the research community will probably weigh in soon enough. Stay tuned. 

Exploring carsharing usage motives

Zipcar reserved

There's a new article in Transportation Research Part A: Policy and Practice that examines carshing in North America and Europe. In "Exploring carsharing usage motives: A hierarchical means-end chain analysis," Tobias Schaefers investigates people's motives for carsharing and some possible implications.

Recently, carsharing has entered a phase of commercial mainstreaming as carsharing providers and urban transportation planners aim at broadening the customer base. In this context, knowledge about the motives of carsharing usage is essential for further growth. Based on a qualitative means-end chain analysis this paper therefore explores usage motives, thus expanding the existing insights from analyses of usage behavior. In a series of laddering interviews with users of a US carsharing service, the underlying hierarchical motive structure is uncovered and four motivational patterns are identified: value-seeking, convenience, lifestyle, and environmental motives. Implications are drawn for applying these insights.

Schaefer cites Susan Shaheen's 2009 "North American Carsharing: 10-Year Retrospective". Shaheen and the Transportation Sustainability Research Center are actively involved in a number of research projects related to carsharing (and bikesharing). You might also be interested in Shaheen's recent publication "Personal Vehicle Sharing Services in North America" that looks at the emerging area of peer-to-peer carsharing, such as Zimride and Lyft.

And of course, if you're looking for more research on carsharing just head over to TRID

Progression of Automobiles - From Horsepower to Processor Power to What?

Google's Self-Driving Car

Today on the Freakonomics, UCLA's Eric Morris has an interesting post titled "From Horse Power to Horsepower to Processing Power" which builds upon his 2007 article ACCESS, "From Horse Power to Horsepower." It's a good overview of the state of driverless cars from a social, legal, and ecomomic standpoint. Pull quote: 

 

Lest I get carried away, it’s important to remember a caveat from the horse manure story. While the auto did eliminate the problem of horse pollution, as we now know it sowed the seeds for vexing new environmental problems of which proponents at the time were blissfully ignorant. How might driverless cars make us be careful what we wished for?
 
In one way, driverless cars promise to cut fuel consumption and emissions, by coordinating car movements in a way that smooths traffic flow and improves aerodynamics through the “platooning” of the vehicles. However, by making car travel so much cheaper, faster and easier, driverless cars may harm the environment by promoting lots more driving. It is true that other technology is currently addressing this problem, with electrification (e.g., the Volt) and many other efficiency improvements like improved transmissions, materials, tires, and aerodynamics. Still, emissions and fuel use will remain a vexing problem that driverless cars could conceivably exacerbate.

 

It'll be interesting to see a similar overview in another 5 years. How much do you think wi

Highway Grants: Roads to Prosperity?

Night Construction II

A new Economic Letter from the Federal Reserve Bank of San Francisco focuses on new research from Sylvain Leduc and Daniel Wilson. From their forthcoming paper, "Roads to Prosperity or Bridges to Nowhere?:Theory and Evidence on the Impact of Public Infrastructure Investment", Leduc and Wilson study the macroeconomic effects of infrastructure investment. 

This research focuses on investment in roads and highways in part because it is the largest component of public infrastructure in the United States. Moreover, the procedures by which federal highway grants are distributed to states help us identify more precisely how transportation spending affects economic activity.

We find that unanticipated increases in highway spending have positive but temporary effects on GSP, both in the short and medium run. The short-run effect is consistent with a traditional Keynesian channel in which output increases because of a rise in aggregate demand, combined with slow-to-adjust prices. In contrast, the positive response of GSP over the medium run is in line with a supply-side effect due to an increase in the economy’s productive capacity.

This research is timley given the prognosis that the Highway Trust Fund will go brankrupt by 2014 all while hoping infrastrcture investment can spur the economy through job creation, as outlined in MAP-21.

Queueing Models for Trajectory-Based Aircraft Operations

Control Tower

ITS Berkeley's Tasos Nikoleris and Mark Hansen have an article in the current issue of Transportation Science. "Queueing Models for Trajectory-Based Aircraft Operations".

This paper develops a queueing model for aircraft arrivals at a single server under trajectory-based flight operations, which are expected to prevail in the Next Generation Air Transportation System. Aircraft are assigned scheduled times of arrival at a server, which they meet with some normally distributed stochastic error. The Clark approximation method is employed to estimate expected queueing delays, and it is shown, through comparison with simulation, that the method yields very accurate estimates. Exact results are derived for a special case in which aircraft are metered into a capacity-constrained area with constant excess time separation between them. This allows analysis of the tradeoff between the “stochastic delay” that results from imperfect adherence to metered times of arrival and the additional “deterministic delay” from metering at a headway above the minimum required.

The article can be found online.

A National PPP to Support Infrastructure Investment?

Construction

A new report from the Brookings Institution calls for a Federal Public-Private Partnership (PPP) for infrastructure investement by potentially streamlining the process. 

To address this problem, countries, states, and provinces around the world have created specialized institutional entities—called PPP units—to fulfill different functions such as quality control, policy formulation, and technical advice. The federal government should establish a dedicated PPP unit to tackle bottlenecks in the PPP process, protect the public interest, and provide technical assistance to states and other public entities that cannot develop the internal capacity necessary to deal with the projects themselves.

The full report can be found on their website

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