published journal article

Integrating demand forecasts into the operational strategies of shared automated vehicle mobility services: spatial resolution impacts

Transportation Letters

Publication Date

November 25, 2020

Author(s)

Michael Hyland, Florian Dandl, Klaus Bogenberger, Hani Mahmassani

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Abstract

This study aims to evaluate and quantify the impact of demand forecast spatial resolution on the operational performance of a shared-use automated vehicle (AV) mobility service (SAMS) fleet. To perform the evaluation, this study employs an agent-based modeling framework that includes user requests, AVs, and an SAMS fleet controller. In the simulation, an SAMS fleet controller dynamically assigns AVs to on-demand user requests and repositions empty AVs throughout the service region to serve expected future demand requests. The fleet controller uses an offline demand forecast model and an online optimization model that jointly assigns AVs to users and repositioning trips. Results indicate that despite demand forecast quality decreasing at higher spatial resolutions, the operational efficiency of the SAMS fleet increases with higher spatial resolution forecasts (i.e. smaller subareas). Results also indicate that there is a significant operational value associated with improving short-term demand forecasts at high spatial resolutions.

Suggested Citation

Michael Hyland, Florian Dandl, Klaus Bogenberger and Hani Mahmassani (2020) “Integrating demand forecasts into the operational strategies of shared automated vehicle mobility services: spatial resolution impacts”, Transportation Letters, 12(10), pp. 671–676. Available at: 10.1080/19427867.2019.1691297.

published journal article

A spatio-temporal decomposition based deep neural network for time series forecasting

Applied Soft Computing

Publication Date

February 1, 2020

Author(s)

Reza Asadi, Amelia Regan

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Suggested Citation

Reza Asadi and Amelia C. Regan (2020) “A spatio-temporal decomposition based deep neural network for time series forecasting”, Applied Soft Computing, 87, p. 105963. Available at: 10.1016/j.asoc.2019.105963.

conference paper

Loop-based travel time measurement

Proceedings of the international conference on applications of advanced technologies in transportation engineering

Publication Date

January 1, 1998

Author(s)

Reinhart D. Kuehne, Joe Palen, Craig Gardner, Stephen Ritchie

Suggested Citation

Reinhart D. Kuehne, Joe Palen, Craig Gardner and Stephen Ritchie (1998) “Loop-based travel time measurement”, in Proceedings of the international conference on applications of advanced technologies in transportation engineering, pp. 175–182.

published journal article

Diurnal temperature and pressure effects on axial turbomachinery stability in solid oxide fuel cell-gas turbine hybrid systems

Journal of Fuel Cell Science and Technology

Publication Date

March 1, 2011

Author(s)

James D. Maclay, Jack Brouwer, Scott Samuelsen

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Suggested Citation

James D. Maclay, Jacob Brouwer and G. Scott Samuelsen (2011) “Diurnal temperature and pressure effects on axial turbomachinery stability in solid oxide fuel cell-gas turbine hybrid systems”, Journal of Fuel Cell Science and Technology, 8(3). Available at: 10.1115/1.4003163.

conference paper

Poster: On the System-Level Effectiveness of Physical Object-Hiding Adversarial Attack in Autonomous Driving

Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security

Publication Date

November 7, 2022

Author(s)

Ningfei Wang, Yunpeng Luo, Takami Sato, Kaidi Xu, Qi Alfred Chen

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Abstract

In Autonomous Driving (AD) systems, perception is both security and safety-critical. Among different attacks on AD perception, object-hiding adversarial attack is one of the most critical ones due to the direct impact on safety-critical driving decisions such as collision avoidance. However, all of the prior works on physical object-hiding adversarial attacks only study the security of the AI component alone rather than with the entire AD system pipeline with closed-loop control. This thus inevitably raises a critical research question: can these prior works actually achieve system-level effects (e.g., vehicle collisions, traffic rule violation) under real-world AD settings with closed-loop control? To answer this critical question, in this work we take the necessary first step by performing the first measurement study on whether and how effective the existing designs can lead to system-level effects. Our early results find that RP2 and FTE, as two representative examples of prior works, cannot achieve any system-level effect in a representative closed-loop AD setup in common STOP sign-controlled road speeds. In the future, we plan to 1) perform a more comprehensive measurement study using both simulated environments and a real vehicle-sized AD R&D chassis; and 2) analyze the measurement study results and explore new attack designs that can better achieve the system-level effect in AD systems.

Suggested Citation

Ningfei Wang, Yunpeng Luo, Takami Sato, Kaidi Xu and Qi Alfred Chen (2022) “Poster: On the System-Level Effectiveness of Physical Object-Hiding Adversarial Attack in Autonomous Driving”, in Proceedings of the 2022 ACM SIGSAC Conference on Computer and Communications Security. New York, NY, USA: Association for Computing Machinery (CCS '22), pp. 3479–3481. Available at: 10.1145/3548606.3563539.

conference paper

Evaluation of general truck management strategies based on integrated simulation studies: Case study of truck lane restriction on I-710 in southern California

Proceedings of the 86th annual meeting of the transportation research board

Publication Date

January 1, 2007

Author(s)

Choong Heon Yang, Amelia Regan

Abstract

Accurate evaluations of general truck management strategies (GTMS) are required in order to identify positive benefits that can be expected to result from implementation. Most GTMS have been studied with primary or even exclusive consideration of the public sector standpoint. Traffic agencies have primarily focused on addressing operational and safety aspects of GTMS. These are important but insufficient because they do not accurately describe the full effects of GTMS. In our research, multi-criteria performance measures are used to reflect and evaluate overall benefits, including the public and private sector standpoints. This study was performed on an approximately 10-mile section of the I-710 corridor in Southern California. This corridor has one of the highest truck volumes in the US. We considered a truck lane restriction strategy because it is regarded as the most appropriate option for this facility. Three types of scenarios were developed to examine the proper number of restricted lanes. The micro traffic simulation models TransCAD and PARAMICS were the primary analytical tools employed in this research. We concluded that scenario 3, in which two lanes out of four to six are restricted, would provide the maximum positive benefits to the public and private sectors. This study also demonstrated the number of restricted lanes is an important factor in the success of the implementation of this strategy. Our simulation model is fairly general and can be used to evaluate other possible GTMS such as weigh in motion and the addition or conversion of one or more lanes to allow trucks only.

Suggested Citation

Choon Heon Yang and Amelia C. Regan (2007) “Evaluation of general truck management strategies based on integrated simulation studies: Case study of truck lane restriction on I-710 in southern California”, in Proceedings of the 86th annual meeting of the transportation research board, p. 18p.

published journal article

Network structure and airline scheduling

J Industrial Economics

Publication Date

June 1, 2004

Author(s)

Jan Brueckner

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Abstract

This paper provides a simple analysis of the effects of network structure on the scheduling, traffic, and aircraft size choices of a monopoly airline. The analysis shows that switching to a hub-and-spoke network leads to increases in both flight frequency and aircraft size, while stimulating local traffic in and out of the hub. In addition, HS networks are shown to be preferred by the airline when travel demand is low, when flights are expensive to operate, and when passengers place a high value on flight frequency but are not excessively inconvenienced by the extra travel time required for a connecting trip. The welfare analysis shows that the flight frequency, traffic volumes, and aircraft size chosen by the monopolist are all inefficiently low under both network types. Moreover, in the most plausible case, the monopolist’s network choice exhibits an inefficient bias toward the HS network, apparently reflecting an excessive desire to economize on the number of flights.

Suggested Citation

Jan K. Brueckner (2004) “Network structure and airline scheduling”, J Industrial Economics, 52(2), pp. 291–312. Available at: 10.1111/j.0022-1821.2004.00227.x.

published journal article

Effects of property taxation on development timing and density: Policy perspective

Brookings-Wharton Papers on Urban Affairs

Publication Date

January 1, 2006

Author(s)

Richard Arnott

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Suggested Citation

Richard Arnott (2006) “Effects of property taxation on development timing and density: Policy perspective”, Brookings-Wharton Papers on Urban Affairs, 2006(1), pp. 189–230. Available at: 10.1353/urb.2006.0015.

published journal article

Modeling determinants of ridesourcing usage: A census tract-level analysis of Chicago

Transportation Research Part C: Emerging Technologies

Publication Date

October 1, 2020

Author(s)

Arash Ghaffar, Suman Mitra, Michael Hyland

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Abstract

Ridesourcing services provided by companies like Uber, Lyft, and Didi have grown rapidly over the past decade and now serve a sizable portion of trips in many metropolitan areas. An understanding of these services (e.g. to whom, where, when, and for what purposes do they provide service?) is critical for regulating, planning, and managing urban multi-modal transportation systems effectively. Unfortunately, little is known about ridesourcing travel because private companies providing ridesourcing services were not previously subject to data sharing requirements. Fortunately, the city of Chicago recently collected and released spatially (census tract) and temporally (15-minute interval) aggregated data on ridesourcing trips collected from private companies. This study analyzes the Chicago ridesourcing data to examine factors influencing ridesourcing usage. The study employs a random-effects negative binomial (RENB) regression approach to model ridesourcing usage. Determinants considered in the model include weekend vs. weekday and weather variables as well as census tract socio-demographics and commute characteristics, land-use variables, places of interest, transit supply, parking features, and crime. The model results indicate ridesourcing demand is higher on days when temperatures are lower, there is less precipitation, and on the weekend, as well as in census tracts with (i) higher household incomes, (ii) a higher percentage of workers who carpool or take transit to work, (iii) a higher percentage of households with zero vehicles, (iv) higher population and employment density, (v) higher land-use diversity, (vi) fewer parking spots and higher parking rates, (vii) more restaurants, and (viii) more homicides. The results also demonstrate a non-linear (and insightful) relationship between ridesourcing demand and transit supply variables. The paper discusses the implications of these model results to inform transportation planning and policymaking as well as future research.

Suggested Citation

Arash Ghaffar, Suman Mitra and Michael Hyland (2020) “Modeling determinants of ridesourcing usage: A census tract-level analysis of Chicago”, Transportation Research Part C: Emerging Technologies, 119, p. 102769. Available at: 10.1016/j.trc.2020.102769.

published journal article

Does Britain or the United States Have the Right Gasoline Tax?

American Economic Review

Publication Date

August 1, 2005

Author(s)

Ian W. H Parry, Kenneth Small

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Suggested Citation

Ian W. H Parry and Kenneth A Small (2005) “Does Britain or the United States Have the Right Gasoline Tax?”, American Economic Review, 95(4), pp. 1276–1289. Available at: 10.1257/0002828054825510.