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

California OKs Driverless Cars

HDR Remap

This week Gov. Jerry Brown signed SB1298, legalizing driverless cars in California. Some people are concerned about the safety risks of these robot cars. At the signing, Google's Sergey Brin said, "You can count on one hand the number of years it will take before ordinary people can experience this." Google's been testing their driverless cars for miles and miles. (For more background, see Sebastian Thrun's TED Talk.)

Autonomous vehicle research has been progressing for decades. It was part of USDOT's IVHS (Intelligent Vehicle and Highway Systems), what we now know as Intelligent Transportation Systems. For the history of research in the field, just look at TRID and how certain concepts have evolved. Autonomous land vehicles (Qbddkmb) shows the clear relationship to some military efforts. The same can be said for Autonomous vehicle guidance (Dcmvgyh). Connected vehicles are a bit trickier since you have to look at Vehicle to roadside communications (Dsbnu) and Vehicle to vehicle communications (Dsbnw), and Vehicular ad hoc networks as well.

So we might not have Herbie the Love Bug quite yet, but researchers are bringing us quite close to it.

 

BART Turns 40

On this day in 1972 BART started running its first train between Fremont and Oakland. On the BART Blog today is a story of one family's account of opening day. BART is also looking for riders to share their memories of the last 40 years, so stay tuned to their Pintrest board. SF Gate also looks back at BART's triumphs of the last 40 years, inlcuding some pictures from the Nixon's tour in November 1972.

For more perspective of the planning process for the BART system, there are several resources in OskiCat, including our collection of BART planning documents and the classic collection of case studies, Great Planning Disasters. You can also find lots of research on BART in TRID.

This is also a great time to revist Jake Coolidge's representation of the BART system that never was, which was based on some of the early planning documents. 

 

Bike Sharing in the United States

Deco Station

This month the Pedestrian and and Bicycling Information Center (a partnership between FHWA and the UNC Highway Research Safety Center) publised a guide to bikeshare programs in the USA. Bike Sharing in the United States: State of the Practice and Guide to Implementation [PDF], "explores the evolution of bike sharing in the US, defines success factors, examines funding models, explains demographic and geographic trends affecting the implementation of programs, recommends a step-by-step approach for implementation in cities in the start-up phase, and discusses measures to increase demand and expansion of existing programs." More information and resources about bikesharing in the US can be found on the PBIC website.

Reducing Environmental Impacts in California through Highspeed Rail, Efficient Cars and Aircraft

CA High-Speed Rail Design Concept: Fresno Station Area Growth

A new paper in Environmental Research Letters by Arizona State's Mikhail Chester and UC Berkeley's Arpad Horvath assess the potential environmental impact of California Highspeed Rail, more efficient automobiles and aricraft for transportation through the California Corridor.

Sustainable mobility policy for long-distance transportation services should consider emerging automobiles and aircraft as well as infrastructure and supply chain life-cycle effects in the assessment of new high-speed rail systems. Using the California corridor, future automobiles, high-speed rail and aircraft long-distance travel are evaluated, considering emerging fuel-efficient vehicles, new train designs and the possibility that the region will meet renewable electricity goals. An attributional per passenger-kilometer-traveled life-cycle inventory is first developed including vehicle, infrastructure and energy production components. A consequential life-cycle impact assessment is then established to evaluate existing infrastructure expansion against the construction of a new high-speed rail system. The results show that when using the life-cycle assessment framework, greenhouse gas footprints increase significantly and human health and environmental damage potentials may be dominated by indirect and supply chain components. The environmental payback is most sensitive to the number of automobile trips shifted to high-speed rail, and for greenhouse gases is likely to occur in 20–30 years. A high-speed rail system that is deployed with state-of-the-art trains, electricity that has met renewable goals, and in a configuration that endorses high ridership will provide significant environmental benefits over existing modes. Opportunities exist for reducing the long-distance transportation footprint by incentivizing large automobile trip shifts, meeting clean electricity goals and reducing material production effects.

The full paper and supplemental data can be found here.

Pedestrian Deaths Increased in 2010. Why?

Text Distraction

NHTSA recently published pedestrian traffic safety anlysis based upon 2010 data.

The 4,280 pedestrian fatalities in 2010 were an increase of 4 percent from 2009, but
a decrease of 13 percent from 2001. In 2010, pedestrian deaths accounted for 13
percent of all traffic fatalities, and made up 3 percent of all the people injured in
traffic crashes.

Highway fatalities continue to decline, so what accounts for the increase in pedestrian deaths? The Washington Post believes it's from pedestrian distraction, such as text messaging. Is that the only factor in play? Probably not, but pedestrian distraction is something researchers are investigating.

"When Distracted Road Users Cross Paths" examines the relationship between distracted drives and distracted pedestrians. The authors conclude, " Ultimately, a safe roadway environment depends on all road users paying attention to where they are going and being aware of other users who might be sharing the road."

"Distraction and pedestrian safety: How talking on the phone, texting, and listening to music impact crossing the street" from the March 2012 issue of Accident Analysis & Prevention studies how college students are affected by the use of handheld multimedia devices while walking. The researchers conclude that policymakers should consider ways to better protect distracted pedestrians.

More articles about pedestrian distraction can be found on TRID.

ITS Library Reopened

IMAG0018

Construction is done in the library. We now have a new wall, some new paint, and new offices. We also have some new hours - we'll be open to the public Monday through Friday from 1:00 PM to 5:00 PM. Thank you for your patience.

Library Closed through August 3

Bridge Closed

UPDATE: The ITS Library will be closed from now until August 3rd, while we move offices and the construction in the library is finished. We will reopen with some fresh paint, another white board, and a couch on August 7th. If you want to return materials, you may do so in the drop box outside O'Brien hall or to other libraries on campus. If you need asistance or have questions, please email us at itslib@berkeley.edu

Construction in the Library

construction zone

Construction is beginning today on the new wall in the library. Most of the work will be done on the weekend, so we don't anticipate any closures during the initial phase of construction, but there will probably be some noise. We'll let you know if any service disruptions occur. Thanks for your patience.

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