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Los Angeles, CA, United States

Vyas G.,Parsons Brinckerhoff | Paleti R.,University of Texas at Austin | Bhat C.,University of Texas at Austin | Goulias K.,University of California at Santa Barbara | And 4 more authors.
Transportation Research Record | Year: 2012

In this paper an estimation is made of a joint household-level model of the number of vehicles owned by a household, the vehicle type choice of each vehicle, the annual mileage on each vehicle, and the individual assigned as the primary driver for each vehicle. A version of the proposed model system currently serves as the engine for a household vehicle composition and evolution simulator, which itself has been embedded in the larger Simulator of Activities, Greenhouse Emissions, Energy, Networks, and Travel (SimAGENT), an activity-based travel and emissions forecasting system for the Southern California Association of Governments planning region.

Ben-Elia E.,Tel Aviv University | Alexander B.,Southern California Association of Governments | Hubers C.,Technical University of Delft | Ettema D.,University Utrecht
Transportation Research Part A: Policy and Practice | Year: 2014

This paper focuses on the interrelationships between ICT, activity fragmentation and travel behaviour. The concept of fragmentation relates to how activities are spatiotemporally reorganized, by subdividing activities into smaller components that are then performed at different times and/or locations, in connection with ICT use. The association between ICT, activity fragmentation and travel relationships remains uncharted. Based on a two-day Dutch communication-activity-travel diary different associations between ICT use, paid work spatiotemporal fragmentation indicators and frequency of travel are specified and tested with Path Analysis Modelling accounting for sociodemographic and land use factors. The results demonstrate that the interrelationships between fragmentation, ICT and travel are quite complex. ICT and fragmentation apparently have a reciprocal relationship with mobile ICT use influencing the degree of spatial fragmentation whereas the usages of sedentary ICT are influenced by the degree of temporal fragmentation. Person-ICT attributes and ICT use mediate the participation in non-work activities, and can replace work and non-work travel. Fragmentation reduces work trips but at the same time restricts non-work personal travel possibilities and can reallocate time for leisure activity and travel. © 2014 Elsevier Ltd.

Barkley T.,Berkeley Transportation Systems Inc. | Hranac R.,Berkeley Transportation Systems Inc. | Fuentes K.,South Bay Cities Council of Governments | Law P.,Southern California Association of Governments
Transportation Research Record | Year: 2011

Automated performance-monitoring systems take in intelligent transportation system sensor data in real time, archive them, and analyze them. These systems are needed to help local agencies identify problem areas, develop improvement plans, and perform before and after evaluations on the impacts of traffic management changes. Research performed in the past few years has demonstrated the utility of these systems for local transportation agencies, particularly for evaluating signal progression quality. However, acquiring the critical data items for existing arterial intelligent transportation systems-signal phase event information-is often a practical challenge because the configuration of the existing system of most arterial systems does not record or communicate signal phase events to a central location. As a solution to that problem, this paper documents an approach to estimate signal phase data with in-pavement vehicle sensors, a data source that is generally available from arterial systems. On many arterial systems, these sensors frequently communicate data from the field to a central traffic management center. The goal of this paper was to make recent arterial progression quality research implementable by developing a method to gather signal phase event data in a way that would be practical for most local transportation agencies, given their existing arterial systems. Two proposed methods were tested on a year's worth of data from a 2-mi arterial corridor in Carson, California. Results showed that sensor data from central traffic management centers could be used to develop accurate measurements of signal phase events when coupled with timing plans.

Bhat C.R.,University of Texas at Austin | Goulias K.G.,University of California at Santa Barbara | Pendyala R.M.,Arizona State University | Paleti R.,Parsons Brinckerhoff | And 3 more authors.
Transportation | Year: 2013

This paper develops and estimates a multiple discrete continuous extreme value model of household activity generation that jointly predicts the activity participation decisions of all individuals in a household by activity purpose and the precise combination of individuals participating. The model is estimated on a sample obtained from the post census regional household travel survey conducted by the South California Association of Governments in the year 2000. A host of household, individual, and residential neighborhood accessibility measures are used as explanatory variables. The results reveal that, in addition to household and individual demographics, the built environment of the home zone also impacts the activity participation levels and durations of households. A validation exercise is undertaken to evaluate the ability of the proposed model to predict participation levels and durations. In addition to providing richness in behavioral detail, the model can be easily embedded in an activity-based microsimulation framework and is computationally efficient as it obviates the need for several hierarchical sub-models typically used in extant activity-based systems to generate activity patterns. © 2013 Springer Science+Business Media New York.

Chen Y.,University of California at Santa Barbara | Ravulaparthy S.,University of California at Santa Barbara | Deutsch K.,University of California at Santa Barbara | Dalal P.,University of California at Santa Barbara | And 6 more authors.
Transportation Research Record | Year: 2011

"Accessibility," defined as the ease (or difficulty) with which opportunities for activity can be reached from a given location, can be measured with the cumulative amount of opportunities from an origin within a given amount of travel time. These indicators can be used in regional planning and modeling efforts to integrate land use and travel demand, and an attempt should be made to calculate these indicators for the smallest geographic area. The primary objective of this paper is to illustrate the creation of realistic space-sensitive and time-sensitive block-level accessibility indicators to track the availability of opportunities. These indicators support the development of an activity-based travel demand model by Southern California Association of Governments to provide second-by-second and parcel-by-parcel modeling and simulation. The indicators also provided the base information for mapping opportunities of access to 15 types of industries at different times during a day. The indicators and their maps were defined for the entire region of Southern California through largely available data that included the Census Transportation Planning Package, Dun & Brad-street postprocessed data, detailed highway networks and travel times from the four-step regional models, and arrival and departure times of workers by industry.

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