conference paper
Best Frennemies? A Characterization of TNC and Transit Users Based on the 2017 NHTS
100th Transportation Research Board (TRB) Annual Meeting
Publication Date
January 1, 2021
Archives: Research Products
working paper
Prices, capacities and service quality in a congestible Bertrand duopoly
Publication Date
September 1, 2005
Author(s)
Areas of Expertise
Abstract
We study the duopolistic interaction between congestible facilities that supply perfect substitutes. Firms are assumed to make sequential decisions on capacities and prices. Since the outcomes directly affect consumers’ time cost of accessing or using a facility, the capacity sharing rule is endogenous. We study this two-stage game for different firm objectives and compare the duopoly outcomes with those under monopoly and at the social optimum. Our findings include the following. First, for profit maximizing firms both capacity provision and service quality, defined as the inverse of time costs of using the facility, are distorted under duopoly: they are below the socially optimal levels. This contrasts with the monopoly outcome, where pricing and capacity provision are such that the monopolist does provide the socially optimal level of service quality. Second, duopoly prices are lower than monopoly prices, but higher than in the social optimum. Hence, while price competition between duopolists yields benefits for consumer, capacity competition is harmful. Third, price-capacity competition implies that higher capacity costs may lead to higher profits for both facilities. Finally, if firms also care about output, this mainly affects pricing behavior; strategic interaction in capacities are much less affected. If duopolists attach a higher weight to output and a correspondingly lower weight to profits, this leads to a deterioration of the quality of service.
conference paper
On activity-based network design problems
20TH INTERNATIONAL SYMPOSIUM ON TRANSPORTATION AND TRAFFIC THEORY (ISTTT 2013)
Publication Date
January 1, 2013
Associated Project
Author(s)
Abstract
This paper examines network design where OD demand is not known a priori, but is the subject of responses in household or user itinerary choices to infrastructure improvements. Using simple examples, we show that falsely assuming that household itineraries are not elastic can result in a lack in understanding of certain phenomena; e.g., increasing traffic even without increasing economic activity due to relaxing of space-time prism constraints, or worsening of utility despite infrastructure investments in cases where household objectives may conflict. An activity-based network design problem is proposed using the location routing problem (LRP) as inspiration. The bilevel formulation includes an upper level network design and shortest path problem while the lower level includes a set of disaggregate household itinerary optimization problems, posed as household activity pattern problem (HAPP) (or in the case with location choice, as generalized HAPP) models. As a bilevel problem with an NP-hard lower level problem, there is no algorithm for solving the model exactly. Simple numerical examples show optimality gaps of as much as 5% for a decomposition heuristic algorithm derived from the LRP. A large numerical case study based on Southern California data and setting suggest that even if infrastructure investments do not result in major changes in link investment decisions compared to a conventional model, the results provide much higher resolution temporal OD information to a decision maker. Whereas a conventional model would output the best set of links to invest given an assumed OD matrix, the proposed model can output the same best set of links, the same daily OD matrix, and a detailed temporal distribution of activity participation and travel from which changes in peak period OD patterns can be observed. (C) 2013 The Authors. Published by Elsevier Ltd.
Suggested Citation
Jee Eun Kang, Joseph Y.J. Chow and Will W. Recker (2013) “On activity-based network design problems”, in . Hoogendoorn, SP and Knoop, VL and VanLint, H (ed.) 20TH INTERNATIONAL SYMPOSIUM ON TRANSPORTATION AND TRAFFIC THEORY (ISTTT 2013). ELSEVIER SCIENCE BV (Procedia social and behavioral sciences), pp. 157–185. Available at: 10.1016/j.sbspro.2013.05.011.Related Publications
published journal article |
Nov 2015
Strategic hydrogen refueling station locations with scheduling and routing considerations of individual vehicles
Transportation Science
published journal article |
Sep 2013
The location selection problem for the household activity pattern problem
Transportation Research Part B: Methodological
published journal article |
Dec 2009
An activity-based assessment of the potential impacts of plug-in hybrid electric vehicles on energy and emissions using 1-day travel data
Transportation Research Part D: Transport and Environment
working paper
A Simultaneous Dynamic Travel And Activites Time Allocation Model
Publication Date
September 1, 1991
Associated Project
Author(s)
Leo J. G. van Wissen, Thomas Golob, Henk J. Meurs
Areas of Expertise
Abstract
In this paper a model is developed and estimated empirically of the allocation of time to out-of-home activities and travel. The model has three important characteristics.First, the allocation of time to out of home activities by individuals is the key concept in the research reported here. Since there exist interdependencies among time usages for different activities, the joint distribution of all relevant out of home activity times has to be taken into account. Consequently the model developed is multivariate.Second, travel is a derived demand. The amount of travel is the result of the spatial activity behaviour of the individual. Of course, the exact relation between activity performance and travel demand is highly complex. The spatial dispersion and quality of activity locations and the scheduling of activities by individuals are both important elements that need to be studied in order to predict total travel demand from a given activity pattern. Here a much simpler approach is taken. It is assumed that total travel time expenditure over a certain time period (i.e. one week) for an activity is proportional to the total amount of time engaged in that activity.The third main feature or the model is its longitudinal character. Longitudinal data have a number of advantages over cross-sectional (see e.g. Hensher, 1985; Davies and Pickles, 1985; van Wissen and Meurs, 1989). From a statistical point of view it allows the estimation of model parameters conditional on non-observed stationary characteristics and individual taste variations. From a theoretical point of view longitudinal data are necessary in order to identify and estimate dynamic processes. In this study only the statistical advantages of longitudinal data will be used.This paper is organized as follows. In section two an overview is given of earlier related work on the allocation of time and travel consequences. In section three the model methodology will be presented. Next, in section four, the data will be described briefly. Section five contains the empirical results of the model estimation. These results are evaluated and some conclusions are drawn in section six.
Suggested Citation
Leo J. van Wissen, Thomas F. Golob and Henk J. Meurs (1991) A Simultaneous Dynamic Travel And Activites Time Allocation Model. Working Paper. Institute of Transportation Studies, UC Irvine: University of California Transportation Center. Available at: https://escholarship.org/uc/item/0pq5099j.Related Publications
working paper |
Jun 1989
Aggression on Roadways
working paper |
Nov 1991
Structural Models of the Effects of the Commute Trip on Travel and Activity Participation
working paper |
Jun 1991
Home Environment Consequences of Commute Travel Impedance
working paper |
Nov 1988
Simultaneous Equation Systems Involving Binary Choice Variables
working paper |
Sep 1991
Court Intervention, The Consent Decree, and The Century Freeway
research report
Development of New Privacy-preserving Method for Traffic Data Collection and Analysis: The Bathtub Model Approach
Areas of Expertise
Abstract
Traditional data collection approaches present significant drawbacks in computational costs and limited privacy protection. This research evaluates the bathtub traffic flow model as a privacy-preserving alternative to traditional methods that require detailed network layouts and individual trip data. The study assesses the feasibility of the bathtub model through calibration and validation using Bluebikes data from Metro Boston, focusing on three key components: the unified relative space paradigm, conservation equations, and the generalized bathtub model. Results demonstrate that the unified relative space paradigm successfully integrates network trips by considering remaining trip distances, though the trip distance distribution exhibited a log-normal pattern rather than the time-independent negative exponential distribution in Vickrey’s original bathtub model. Conservation equations for total trips and trip-miles traveled showed high accuracy, and the generalized bathtub model yielded accurate results, particularly for space-mean speed. This novel approach preserves privacy by eliminating the need for origin-destination data while still effectively capturing network dynamics.
Related Publications
policy brief |
Jan 2025
Using a “Bathtub Model” to Analyze Travel Can Protect Privacy While Providing Valuable Insights
Preprint Journal Article |
Sep 2023
Priority Queue Formulation of Agent-Based Bathtub Model for Network Trip Flows in the Relative Space
working paper
An Empirical Investigation of the Underlying Behavioral Processes of Trip Chaining
Publication Date
August 1, 2002
Author(s)
Working Paper
UCI-ITS-AS-WP-02-6
Areas of Expertise
Abstract
Trip chaining is a phenomenon that has a significant impact on urban transportation and activity systems. This paper argues that an appropriate representation of the underlying behavioral processes in models of trip chaining is crucial to the capability and reliability of the models. To examine the behavioral processes, data on the complete processes of activity scheduling and trip chaining were collected with a computerized survey instrument, REACT!. The scheduling horizons of sojourn activities were analyzed with contingency tables. The results of this analysis indicate that some of the decision elements entailed in trip chaining were opportunistically formed within constraints set by previously planned activities. While engaged in earlier activities, individuals might see opportunities of carrying out certain activities at different locations occurring later in the day. The decisions as to whether to take these opportunities or not would depend on their evaluation of scheduling feasibility (e.g., the travel time required to reach these activities). However, the analysis also illustrates that some trip chains were indeed executed as planned, suggesting optimality and potential routine behavior. Based on the empirical evidence, transactional opportunistic planning within a constrained environment is viewed as a potential behavioral model for trip chaining behavior.
Suggested Citation
Ming-Sheng Lee and Michael G. McNally (2002) An Empirical Investigation of the Underlying Behavioral Processes of Trip Chaining. Working Paper UCI-ITS-AS-WP-02-6. ITS-Irvine. Available at: https://escholarship.org/uc/item/2gt6s9s9. published journal article
Impacts of highway congestion on freight operations: Perceptions of trucking industry managers
Transportation Research Part A: Policy and Practice
Publication Date
August 1, 2001
Author(s)
Abstract
To better understand how road congestion adversely affects trucking operations, we surveyed approximately 1200 managers of all types of trucking companies operating in California. More than 80% of these managers consider traffic congestion on freeways and surface streets to be either a “somewhat serious” or “critically serious” problem for their business. A structural equations model (SEM) is estimated on these data to determine how five aspects of the congestion problem differ across sectors of the trucking industry. The five aspects were slow average speeds, unreliable travel times, increased driver frustration and morale, higher fuel and maintenance costs, and higher costs of accidents and insurance. The model also simultaneously estimates how these five aspects combine to predict the perceived overall magnitude of the problem. Overall, congestion is perceived to be a more serious problem by managers of trucking companies engaged in intermodal operations, particularly private and for-hire trucking companies serving airports and private companies serving rail terminals. Companies specializing in refrigerated transport also perceive congestion to be a more serious overall problem, as do private companies engaged in LTL operations. The most problematic aspect of congestion is unreliable travel times, followed by driver frustration and morale, then by slow average speeds. Unreliable travel times are a significantly more serious problem for intermodal air operations. Driver frustration and morale attributable to congestion is perceived to be more of a problem by managers of long-haul carriers and tanker operations. Slow average speeds are also more of a concern for airport and refrigerated operations. (C) 2001 Elsevier Science Ltd. All rights reserved.
Suggested Citation
Thomas F. Golob and Amelia C. Regan (2001) “Impacts of highway congestion on freight operations: Perceptions of trucking industry managers”, Transportation Research Part A: Policy and Practice, 35(7), pp. 577–599. Available at: 10.1016/s0965-8564(00)00008-2. published journal article
AdNoC: Runtime adaptive network-on-chip architecture
IEEE Transactions on Very Large Scale Integration (VLSI) Systems
Publication Date
February 1, 2012
Author(s)
Mohammad Al Faruque, Thomas Ebi, J org Henkel
Suggested Citation
Mohammad Abdullah Al Faruque, Thomas Ebi and J org Henkel (2012) “AdNoC: Runtime adaptive network-on-chip architecture”, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 20(2), pp. 257–269. Available at: 10.1109/tvlsi.2010.2094215. research report
Effects of Tax Reform on the Demand for Owner-Occupied Housing : A Microsimulation Approach
Publication Date
January 1, 1984
Author(s)
David Brownstone, Peter Englund, Mats Persson
Report Number
03478769 (ISSN)
Abstract
The paper analyzes the effects on the demand for owner-occupied housing that are likely to result from the Swedish 1983-85 tax reform. This is done by means of a microsimulation model which takes into account the dichotomous nature of the demand for housing: the consumers choose the mode of tenure (owning versus renting) as well as the quantity of housing conditional on the choice of the mode of tenure. The tax reform consists of a general reduction of marginal tax rates (i.e. an increase in disposable income) together with limitations in the deductibility of mortgage interests. The simulations show that this will cause an increase in home-ownership in the sense that more households will demand owner-occupied housing. At the same time, however, the households will demand smaller houses in the average, and thus aggregate demand for small and medium-sized units will increase while demand for large units will fall sharply.
Suggested Citation
David Brownstone, Peter Englund and Mats Persson (1984) Effects of Tax Reform on the Demand for Owner-Occupied Housing : A Microsimulation Approach. 03478769 (ISSN). Stockholm: IIES, p. 43. Available at: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-41316 (Accessed: July 12, 2010). conference paper
Performance evaluation of navigation using LEO satellite signals with periodically transmitted satellite positions
Proceedings of the 2019 international technical meeting of the institute of navigation
Publication Date
February 1, 2019
Author(s)
Abstract
The navigation performance with low Earth orbit (LEO) satellite signals is evaluated. The navigation framework used to perform this evaluation tightly integrates a vehicle’s inertial navigation system (INS) with Doppler and pseudorange measurements from LEO satellites. The following scenario is considered. A vehicle has access to global navigation satellite system (GNSS) signals and a priori, uncertain information about LEO satellite states. The vehicle navigates by tightly integrating GNSS pseudorange measurements with its onboard INS. During the period when GNSS signals are available, the vehicle tracks the LEO satellites from pseudorange and Doppler measurements, refining estimates about their states. Next, GNSS signals are assumed to be unavailable. The vehicle transitions to a simultaneous tracking and navigation (STAN) mode where it simultaneously tracks the LEO satellites and navigates by integrating pseudorange and Doppler measurements made on the LEO satellites with its onboard INS. The performance of this navigation framework is evaluated for two cases: when the LEO satellites periodically transmit their position and when the do not transmit such information. Simulation results with existing LEO satellite constellations pertaining to Orbcomm and Globalstar as well as the future satellite constellation pertaining to Starlink are presented. It was assumed that the LEO satellites are periodically transmitting their positions. These simulation results consider an unmanned aerial vehicle (UAV) equipped with a tactical-grade inertial measurement unit (IMU) navigating for 81.6 km in 600 seconds, in which GNSS signals were only available for the first 100 seconds. It is demonstrated that the final position error of the INS-Orbcomm-Globalstar system was 93.01 m while the INS-Starlink system was 9.81 m. The position root mean squared error (RMSE) of the INS-Orbcomm-Globalstar system was 58.59 m while the INS-Starlink system was 10.13 m. Experimental results with existing Orbcomm LEO satellites are presented in which only Doppler measurements were made on two available satellites. The experimental results were conducted on a ground vehicle equipped with a tactical-grade IMU that traversed 7.5 km in 258 seconds, in which GNSS signals were only available for the first 30 seconds. It is demonstrated that the final position error of the INS without GNSS signals was 3.73 km and the position RMSE was 1.42 km. On the other hand, the final position error of the INS-Orbcomm system was 233.3 m and the position RMSE was 188.6 m when the position of the satellite was decoded from its transmitted message. If such position was not decoded and was estimated only from the STAN framework, the final position error was 476.3 m and the position RMSE was 195.6 m.