published journal article
Inverse optimization with endogenous arrival time constraints to calibrate the household activity pattern problem
Transportation Research Part B: Methodological
Publication Date
March 1, 2012
Area of Expertise: Unspecified
conference paper
A geospatial data fusion framework to quantify variations in electric vehicle charging demand
Proceedings of the 4th ACM SIGSPATIAL International Workshop on Advances in Resilient and Intelligent Cities
Publication Date
November 18, 2021
Author(s)
Abstract
Electric vehicles (EV) are an emerging mode of transportation, and big cities in the United States have witnessed an ever-growing demand for EV usage. The primary benefit of EVs is the high fuel efficiency by using only electricity, and hence lowers the dependency on fossil fuels and significantly reduces greenhouse gas emissions. Although the number of EVs has increased, the availability of EV charging stations for public use has been disproportionate to its demand. More recently, populations residing in the Southern California region have been faced with challenges such as range anxiety owing to the uneven spatial distribution of charging stations throughout the region. As the EV population continues to expand, identifying hotspots of EV charging and barriers to the equitable access of charging stations have gained much importance. Our study uses a geospatial data fusion approach with spatial statistics to combine EV charging station data, land use information, and American Community Survey (ACS) data at the census block group level in Orange County, California to discover optimal locations to broaden the EV charging network and identify potential equity issues surrounding charging station placements.
Suggested Citation
Mankin Law and Avipsa Roy (2021) “A geospatial data fusion framework to quantify variations in electric vehicle charging demand”, in Proceedings of the 4th ACM SIGSPATIAL International Workshop on Advances in Resilient and Intelligent Cities. New York, NY, USA: Association for Computing Machinery (ARIC '21), pp. 23–26. Available at: 10.1145/3486626.3493429. conference paper
Estimating commute time and distance for human subjects in air pollution epidemiological studies
Proceedings of the conference of the international society of exposure assessment, seoul, korea
Publication Date
August 1, 2010
Author(s)
Suggested Citation
J. Wu and D. Houston (2010) “Estimating commute time and distance for human subjects in air pollution epidemiological studies”, in Proceedings of the conference of the international society of exposure assessment, seoul, korea. conference paper
A preliminary analysis of the environmental impacts of the clean truck program in the alameda corridor, California
Proceedings of the 89th annual meeting of the transportation research board
Publication Date
January 1, 2010
Abstract
The San Pedro Bay Ports (SPBP) of Los Angeles and Long Beach in Southern California is one of the largest port container complexes in the world, and the largest one is the United States. To decrease the air pollution associated with port operations, a number of measures have been adopted, including the Clean Trucks Program, which was introduced in 2008 to modernizing and clean up the fleet of drayage trucks serving the SPBP. The objective of this paper is to quantify the reduction in emissions attributable to the Clean Trucks Program, with a focus on Nitrogen Oxide (NOx) and Particulate Matter (PM2.5). The authors approach is innovative as it relies on micro-simulation (TransModeler) to capture the link between congestion and pollutant emissions. The authors find that the Clean Trucks Program could contribute significantly to the emissions of NOx (~27%) and PM2.5 (~25%) for all the freeway traffic in the study area. These preliminary results suggest that the Clean Trucks Program is promising, but its cost-effectiveness should be analyzed.
Suggested Citation
Roberto Ayala, Jean-Daniel Saphores, Stephen G. Ritchie, Gunwoo Lee and Mana Sangkapichai (2010) “A preliminary analysis of the environmental impacts of the clean truck program in the alameda corridor, California”, in Proceedings of the 89th annual meeting of the transportation research board, p. 16p. conference paper
Advancing Gross Vehicle Weight Rating Classification Through the Integration of Inductive Loop and Side Fire Camera System
Proceedings, 104th Annual Meeting of the Transportation Research Board
Publication Date
January 1, 2025
Author(s)
Abstract
Gross Vehicle Weight Rating (GVWR)-based vehicle activity data is widely used in freight planning, fuel efficiency evaluation, and on-road emission estimation. However, a vehicle’s GVWR remains challenging to obtain using existing highway sensor infrastructure. This paper describes a novel approach to acquire GVWR-based classification data through the fusion of two complementary infrastructure-based sensing technologies: inductive loop sensors and side-fire video cameras. While inductive loops are widely deployed in the U.S., they only provide single-dimensional data with limited information. Side-fire cameras can offer richer details to enhance vehicle classification. Accordingly, an open-source intelligence (OSINT) method was used to establish a GVWR-based vehicle dictionary, linking vehicle specifications from online data sources to GVWR classes. A dataset comprising 9,154 vehicle inductive loop signatures paired with images was then collected and annotated according to the pre-defined dictionary. Next, signature-based and image-based classification models were developed for GVWR classification. Each model was designed to function independently. A signature-based GVWR classification model was trained with a multi-layer perceptron (MLP) neural net architecture and optimized through the implementation of a weighted cross-entropy loss function. A two-stage image-based GVWR classification framework was designed to extract vehicle objects and classify them based on the GVWR scheme. Finally, a linear fusion model was implemented to combine the output of the signature- and image-based models to achieve an improvement over each standalone classification model. The sensor fusion framework significantly outperformed each individual sensing technology, achieving an average correct classification rate of 0.97 and an score of 0.96, which surpasses state-of-the-art methods.
Suggested Citation
Guoliang Feng, Yiqiao Li, Andre Tok and Stephen G. Ritchie (2025) “Advancing Gross Vehicle Weight Rating Classification Through the Integration of Inductive Loop and Side Fire Camera System”, in Proceedings, 104th Annual Meeting of the Transportation Research Board. Washington, D.C.. published journal article
The role of renter burden and affordable units at risk in city-level housing inadequacy
Cities
Publication Date
October 1, 2025
Author(s)
John R. Hipp, Brendan S. Poon, Jae Hong Kim
Abstract
While substantial research has studied the effects of government-assisted provision of affordable housing units, little is known about the challenges that arise when the stock of affordable units is increasingly at risk due to the approaching expiration of their low-cost status. This study provides an empirical investigation of how city-level at-risk affordable units, as well as median rent and rent burden, relate to housing inadequacy using data for all cities with population greater than 5000 in the U.S. The results indicate a direct positive relationship between rent burden (relative to income) and housing inadequacy in multilevel models accounting for the county context of these cities. This positive relationship is strongest in counties with large population or high average income. Cities with higher (nominal) median rent have less housing inadequacy, particularly in counties with larger populations. Finally, the presence of more affordable units, as well as more at-risk affordable units, is associated with greater housing inadequacy, calling for more attention not only to the expansion of these units but also to the ways affordable housing stock is managed and preserved. Our findings indicate the importance of policies to reduce both rent burdens and the presence of at-risk units, such as proactive renewal of affordability covenants. Moreover, our findings highlight the need for additional research that addresses how renters and developers respond to incentives created by affordable housing dynamics.
Suggested Citation
John R. Hipp, Brendan S. Poon and Jae Hong Kim (2025) “The role of renter burden and affordable units at risk in city-level housing inadequacy”, Cities, 165, p. 106086. Available at: 10.1016/j.cities.2025.106086. conference paper
Performance studies of a network adaptive traffic control algorithm via simulation model
ITSC 2001. 2001 IEEE intelligent transportation systems. Proceedings (cat. No.01TH8585)
Publication Date
January 1, 2001
Author(s)
Suggested Citation
Wann-Ming Wey and R. Jayakrishnan (2001) “Performance studies of a network adaptive traffic control algorithm via simulation model”, in ITSC 2001. 2001 IEEE intelligent transportation systems. Proceedings (cat. No.01TH8585). IEEE, pp. 663–668. Available at: 10.1109/itsc.2001.948739. conference paper
Using mesoscopic traffic simulation in a seismic risk analysis framework applied to a downtown Los Angeles network
Proceedings of the 89th annual meeting of the transportation research board
Publication Date
January 1, 2010
Author(s)
Abstract
Previous efforts to quantify and estimate the effect of seismic disruptions on the performance of the transportation network have relied on traditional trip-based static traffic assignment methods to estimate and compare network flows under base and damaged cases. Such static assignments with the well-known problem of unrealistically high volume/capacity ratios on congested links, are questionable for predicting the post-earthquake peak-period travel times when links are disabled. This paper introduces the use of mesoscopic traffic simulation in a seismic risk analysis (SRA) framework. This study assesses seismic risk in terms of potential travel time increases in a study area incorporating the site of the Downtown Los Angeles bridge failures during the 1994 Northridge earthquake. This study successfully obtained system risk curves of network-wide travel time increases, and also took advantage of vehicle trajectory output to obtain risk curves of travel time increases for specific origin-destination (OD) pairs.
Suggested Citation
Pierre Auza, R. Jayakrishnan and Masanobu Shinozuka (2010) “Using mesoscopic traffic simulation in a seismic risk analysis framework applied to a downtown Los Angeles network”, in Proceedings of the 89th annual meeting of the transportation research board, p. 20p. published journal article
Safe streets for some: A review of local active transportation responses across the U.S. during the COVID-19 pandemic
Journal of Transport & Health
Publication Date
May 1, 2023
Author(s)
Matthew Dean, Kaelin A. Amaya, Jennifer Hall, Kalinda Marie Gupta, Rachael T. Panik, Jeanette Gustat, Angie L. Cradock
Abstract
Introduction & research objectives The COVID-19 pandemic significantly disrupted daily travel. This paper contrasts 51 US cities’ responses, namely street reallocation criteria and messaging related to physical activity (PA) and active transportation (AT) during the early months of the pandemic. This study can be utilized by cities for aiding in the creation of locally responsive policies that acknowledge and remedy a lack of safe active transportation. Methods A content analysis review was conducted of city orders and documents related to PA or AT for the largest city by population in all 50 US states and the District of Columbia. Authoritative documents issued from each city’s public health declaration (ca. March 2020) to September 2020 were reviewed. The study obtained documents from two crowdsourced datasets and municipal websites. Descriptive statistics were used to compare policies and strategies, with a focus on reallocation of street space. Results A total of 631 documents were coded. Considerable variation existed in city responses to COVID-19 that impacted PA and AT. Most cities’ stay-at-home orders explicitly permitted outdoor PA (63%) and many encouraged PA (47%). As the pandemic continued, 23 cities (45%) had pilot programs that reallocated street space for non-motorized road users to recreate and travel. Most cities explicitly mentioned a rationale for the programs (e.g., to provide space for exercise (96%) and to alleviate crowding or provide safe AT routes (57%)). Cities used public feedback to guide placement decisions (35%) and several welcomed public input to adjust initial actions. Geographic equity was a criterion in 35% of programs and 57% considered inadequately sized infrastructure in decision-making. Conclusions If cities want to emphasize AT and the health of their citizens, safe access to dedicated infrastructure needs to be prioritized. More than half of study cities did not instate new programs within the first 6 months of the pandemic. Cities should study peer responses and innovations to inform and create locally responsive policies that can acknowledge and remedy a lack of safe AT.
Suggested Citation
Matthew D. Dean, Kaelin A. Amaya, Jennifer Hall, Kalinda Marie Gupta, Rachael T. Panik, Jeanette Gustat and Angie L. Cradock (2023) “Safe streets for some: A review of local active transportation responses across the U.S. during the COVID-19 pandemic”, Journal of Transport & Health, 30, p. 101603. Available at: 10.1016/j.jth.2023.101603. published journal article
Using bilateral trading to increase ridership and user permanence in ridesharing systems
Transportation Research Part E: Logistics and Transportation Review
Publication Date
June 1, 2017