working paper

Measuring the Impact of Efficient Household Travel Decisions on Potential Travel Time Savings and Accessibility Gains

Publication Date

December 1, 2000

Author(s)

Will Recker, Chienho Chen, Michael McNally

Working Paper

UCI-ITS-WP-00-10, UCI-ITS-AS-WP-00-11

View working paper

Abstract

Using the conceptual framework of time-space geography, this paper incorporates both spatio-temporal constraints and household interaction effects into a meaningful measure of the potential of a household to interact with the built environment. Within this context, personal accessibility is described as a measure of the potential ability of individuals within a household not only to reach activity opportunities, but to do so with sufficient time available for participation in those activities, subject to the spatio-temporal constraints imposed by their daily obligations and transportation supply environment. The incorporation of activity-based concepts in the measurement of accessibility as a product of travel time savings not only explicitly acknowledges a temporal dimension in assessing the potential for spatial interaction but also expands the applicability of accessibility consideration to such real-world policy options as the promotion of ride-sharing and trip chaining behaviors. An empirical application of the model system provides an indication of the potential of activity-based modeling approaches to assess the bounds on achievable improvements in accessibility and travel time based on daily household activity patterns. It also provides an assessment of roles for trip chaining and ride-sharing as potentially effective methods to facilitate transportation policy objectives.

Suggested Citation

Will Recker, Chienho Chen and Michael G. McNally (2000) Measuring the Impact of Efficient Household Travel Decisions on Potential Travel Time Savings and Accessibility Gains. Working Paper UCI-ITS-WP-00-10, UCI-ITS-AS-WP-00-11. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/77j8x1zs.

published journal article

Examining mobility outcomes in the housing choice voucher program: Neighborhood poverty, employment, and public school quality

Cityscape (Washington, D.C.)

Publication Date

January 1, 2013

Author(s)

Victoria Basolo

View published journal article

Abstract

Low-income housing policies seeking to deconcentrate poverty and increase opportunities through mobility have produced mixed results. The Moving to Opportunity (MTO) program, for example, resulted in some beneficial outcomes for low-income households moving from high-to low-poverty neighborhoods, but it did not produce the widespread positive effects anticipated by many policymakers and researchers. The Housing Choice Voucher Program (HCVP) does not require moves to low-poverty neighborhoods, as MTO did, but rather it relies on a weaker policy of choice to achieve more income-diverse neighborhoods. As compared with what researchers have learned about the MTO participants, less is known concerning the mobility behavior and outcomes of HCVP recipients. Using survey data from voucher holders under the jurisdiction of two local housing authorities in California combined with secondary data from multiple sources, this article examines a range of outcomes, including neighborhood poverty rates, employment, and school quality, associated with mobility in the HCVP. The results of the analyses show that movers did not have better outcomes than non-movers but, compared with conditions in their previous residence, movers lived in neighborhoods with lower poverty rates and better school quality after they moved. By contrast, employment for movers dropped significantly from before to after their moves.

Suggested Citation

Victoria Basolo (2013) “Examining mobility outcomes in the housing choice voucher program: Neighborhood poverty, employment, and public school quality”, Cityscape (Washington, D.C.), 15(2), pp. 135–153. Available at: https://www.jstor.org/stable/41959116.

published journal article

Development of a microscopic activity-based framework for analyzing the potential impacts of transportation control measures on vehicle emissions

Transportation Research Part D: Transport and Environment

Publication Date

November 1, 1999

Author(s)

Will Recker, Arun Parimi

View published journal article

Abstract

The 1990 Clean Air Act Amendments (CAAA) and: the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) have defined a set of transportation control measures to counter the increase in the vehicle emissions and energy consumption due to increased travel. The value of these TCM strategies is unknown as there is limited data available to measure the travel effects of individual TCM strategies and the models are inadequate in forecasting changes in travel behavior resulting from these strategies. The work described in this paper begins to provide an operational methodology to overcome these difficulties so that the impacts of the policy mandates of both CAAA and ISTEA can be assessed. Although the framework, as currently developed, falls well short of actually forecasting changes in traveler behavior relative to policy options designed to encourage emissions reduction, the approach can be useful in estimating upper bounds of certain policy alternatives in reducing vehicle emissions. Subject to this important limitation, the potential of transportation policy options to alleviate vehicle emissions is examined in a comprehensive activity-based approach. Conclusions are drawn relative to the potential emissions savings that can be expected from efficient trip chaining behavior, ridesharing among household members, as well as from technological advances in vehicle emissions control devices represented by replacing all of the vehicles in the fleet by vehicles conforming to present-day emissions technology. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

Suggested Citation

W.W. Recker and A. Parimi (1999) “Development of a microscopic activity-based framework for analyzing the potential impacts of transportation control measures on vehicle emissions”, Transportation Research Part D: Transport and Environment, 4(6), pp. 357–378. Available at: 10.1016/s1361-9209(99)00014-0.

book/book chapter

A Panel-Based Evaluation of the San Diego I-15 Carpool Lanes Project

Publication Date

January 1, 1997

Author(s)

Thomas Golob, Ryuichi Kitamura, Janusz Supernak

View book/book chapter

Suggested Citation

Thomas F. Golob, Ryuichi Kitamura and Janusz Supernak (1997) “A Panel-Based Evaluation of the San Diego I-15 Carpool Lanes Project”, in T.F. Golob, R. Kitamuraand L. Long (eds.) Panels for Transportation Planning. Boston, MA: Springer US, pp. 97–128. Available at: 10.1007/978-1-4757-2642-8_4.

published journal article

Scene-Graph Augmented Data-Driven Risk Assessment of Autonomous Vehicle Decisions

IEEE Transactions on Intelligent Transportation Systems

Publication Date

July 1, 2022

Author(s)

Shih-Yuan Yu, Arnav Vaibhav Malawade, Deepan Muthirayan, Pramod P. Khargonekar, Mohammad Al Faruque

View published journal article

Abstract

There is considerable evidence that evaluating the subjective risk level of driving decisions can improve the safety of Autonomous Driving Systems (ADS) in both typical and complex driving scenarios. In this paper, we propose a novel data-driven approach that uses scene-graphs as intermediate representations for modeling the subjective risk of driving maneuvers. Our approach includes a Multi-Relation Graph Convolution Network, a Long-Short Term Memory Network, and attention layers. To train our model, we formulate subjective risk assessment as a supervised scene classification problem. We evaluate our model on both synthetic lane-changing datasets and real-driving datasets with various driving maneuvers. We show that our approach achieves a higher classification accuracy than the state-of-the-art approach on both large (96.4% vs. 91.2%) and small (91.8% vs. 71.2%) lane-changing synthesized datasets, illustrating that our approach can learn effectively even from small datasets. We also show that our model trained on a lane-changing synthesized dataset achieves an average accuracy of 87.8% when tested on a real-driving lane-changing dataset. In comparison, the state-of-the-art model trained on the same synthesized dataset only achieved 70.3% accuracy when tested on the real-driving dataset, showing that our approach can transfer knowledge more effectively. Moreover, we demonstrate that the addition of spatial and temporal attention layers improves our model’s performance and explainability. Finally, our results illustrate that our model can assess the risk of various driving maneuvers more accurately than the state-of-the-art model (86.5% vs. 58.4%, respectively).

Suggested Citation

Shih-Yuan Yu, Arnav Vaibhav Malawade, Deepan Muthirayan, Pramod P. Khargonekar and Mohammad Abdullah Al Faruque (2022) “Scene-Graph Augmented Data-Driven Risk Assessment of Autonomous Vehicle Decisions”, IEEE Transactions on Intelligent Transportation Systems, 23(7), pp. 7941–7951. Available at: 10.1109/TITS.2021.3074854.

published journal article

Globally Optimal Assignment Algorithm for Collective Object Transport Using Air–Ground Multirobot Teams

IEEE Transactions on Control Systems Technology

Publication Date

January 1, 2024

Author(s)

Tatsuya Miyano, Justin Romberg, Magnus Egerstedt

View published journal article

Abstract

We consider the problem of collectively transporting multiple objects using air–ground multirobot teams. The objective is to find the optimal matching between the objects and aerial/ground robots that minimizes the energy of the overall system. We reveal the local optimality criteria for this combinatorial problem and prove that combining a branch and bound algorithm with a negative-cycle canceling algorithm (NCCA) yields an efficient algorithm that provides the globally optimal solution of the problem. Numerical experiments demonstrate the performance on practical problems.

Suggested Citation

Tatsuya Miyano, Justin Romberg and Magnus Egerstedt (2024) “Globally Optimal Assignment Algorithm for Collective Object Transport Using Air–Ground Multirobot Teams”, IEEE Transactions on Control Systems Technology, 32(1), pp. 258–265. Available at: 10.1109/TCST.2023.3291880.

policy brief

Shared Autonomous Mobility Services Show Promise for Increasing Access to Employment in Southern California

Publication Date

May 1, 2020

Author(s)

Arash Ghaffar, Michael Hyland, Navjyoth Sarma, Suman Mitra, Tanjeeb Ahmed

View policy brief

Abstract

Workers in Southern California currently face transportation related challenges accessing employment opportunities, including but not limited to high parking costs and/or limited parking availability in dense employment and residential areas; long commute distances between residential areas and employment opportunities; and poor transit service quality in many areas. These challenges are particularly burdensome for low-income households that may not have access to a personal vehicle and/or live in job-poor neighborhoods, as having a personal vehicle may be the only viable way to get to work.

Suggested Citation

Arash Ghaffar, Michael Hyland, Navjyoth Sarma, Suman Mitra and Tanjeeb Ahmed (2020) Shared Autonomous Mobility Services Show Promise for Increasing Access to Employment in Southern California. Policy Brief. UC ITS. Available at: https://doi.org/10.7922/g24f1p14.

published journal article

Simulation studies of information propagation in a self-organizing distributed traffic information system

Transportation Research Part C: Emerging Technologies

Publication Date

October 1, 2005

Author(s)

Xu Yang, Will Recker

View published journal article

Suggested Citation

Xu Yang and Will Recker (2005) “Simulation studies of information propagation in a self-organizing distributed traffic information system”, Transportation Research Part C: Emerging Technologies, 13(5-6), pp. 370–390. Available at: 10.1016/j.trc.2005.11.001.

published journal article

A Comparative Assessment of Travel Characteristics for Neo-Traditional Developments

Transportation Research Record: Journal of the Transportation Research Board

Publication Date

January 1, 1993

Author(s)

Michael McNally, Sherry Ryan

View published journal article

Abstract

The primary intent of this paper is to explore the claim that transportation benefits can be derived from neotraditional neighborhood design. Conventional transportation planning models are used as tools to evaluate the performance differences of two hypothetical street networks designed to replicate a neotraditional and a conventional suburban community. Relative transportation benefits are measured in terms of vehicle-miles traveled, average trip lengths, and congestion on links and at intersections. This comparison provides an assessment of how well the two networks in question deal with trips generated by the activities which they serve. All aspects of the modeled communities are held constant except for the actual configuration of the networks. The results of this evaluation indicate that equivalent levels of activity (defined by the land uses within the community) can produce greater congestion with conventional network structures and that corresponding average trip lengths are generally longer. The ultimate goal is to determine if one network type, because of the nature of its design, can result in a more efficient transportation system. The results indicate that neotraditional designs can improve system performance.

Suggested Citation

Michael G. McNally and Sherry Ryan (1993) “A Comparative Assessment of Travel Characteristics for Neo-Traditional Developments”, Transportation Research Record: Journal of the Transportation Research Board [Preprint], (1400). Available at: https://onlinepubs.trb.org/Onlinepubs/trr/1993/1400/1400-010.pdf.

published journal article

Plant species richness, green spaces, and preterm birth risk in urban areas

Environment International

Publication Date

August 1, 2025

Author(s)

Mengyi Li, Qiping Fan, Yi Sun, Tarik Benmarhnia, Jiu-Chiuan Chen, Anqi Jiao, John Molitor, David A. Sacks, Jeff M. Slezak, Vicki Y. Chiu, Chantal C. Avila, Darios Getahun, Jun Wu

View published journal article

Abstract

Background Growing evidence suggests that urban biodiversity may influence human health, though this relationship remains incompletely understood. While green spaces have shown beneficial effects on birth outcomes, the specific role of plant species richness has not been investigated in relation to preterm birth (PTB, <37 weeks’ gestation). Methods Using Kaiser Permanente Southern California electronic health records (2015–2021), we analyzed 232,452 births to examine associations between plant species richness and PTB. Plant species richness was assessed at the maternal neighborhood level, defined using circular buffers of 1.5 km around maternal residences. Results We found that increased plant species richness was associated with decreased PTB risk (adjusted odds ratio per interquartile range: 0.959, 95 % CI: 0.941, 0.977). The observed association persisted after further adjustment for multiple green space indicators. The proportions of mediation effects attributable to mean temperature during pregnancy ranged from 7.0 % to 7.8 % across plant species diversity indicators. In the subgroup analysis, plant species diversity demonstrated significantly stronger protective associations against PTB among mothers exposed to higher levels of Ozone, high ambient temperatures, and those gave birth during the pandemic period. Conversely, protective associations were more pronounced among mothers with lower NO2 exposure during pregnancy. Notably, the significant relationship between plant species richness and reduced PTB persisted in pandemic-period analyses after adjusting for COVID-19 infection during pregnancy. Conclusions Our findings highlight a complex interplay of sociodemographic and environmental factors influencing PTB risks and underscore the critical need for public health interventions that consider the unique attributes of urban green space.

Suggested Citation

Mengyi Li, Qiping Fan, Yi Sun, Tarik Benmarhnia, Jiu-Chiuan Chen, Anqi Jiao, John Molitor, David A. Sacks, Jeff M. Slezak, Vicki Y. Chiu, Chantal C. Avila, Darios Getahun and Jun Wu (2025) “Plant species richness, green spaces, and preterm birth risk in urban areas”, Environment International, 202, p. 109644. Available at: 10.1016/j.envint.2025.109644.