@article{ghimire_bardaka_2024, title={Do low-income households walk and cycle to reduce their transport costs? Insights from the 2017 US National Household Travel Survey}, volume={4}, ISSN={["1556-8334"]}, DOI={10.1080/15568318.2024.2338724}, abstractNote={Low-income populations are disadvantaged in a car-dependent society despite car ownership and could be using walking and cycling to reduce their travel costs. This study explores how low-income households with and without cars living in various geographies disproportionately use walking and cycling to save money in comparison to higher-income households. Data from the 2017 National Household Travel Survey is used to investigate the variation in walking and cycling behavior among three groups of households: (1) carless low-income households, (2) low-income households with cars, and (3) higher-income households. Generalized ordered logistic regression models are estimated to examine how the probability of using active travel to save money varies by household type, location (urban, suburban, rural) and other socioeconomic attributes. We find that low-income households are more likely to walk or cycle to save money on transportation compared to higher-income households. Carless low-income households present a higher probability to use active travel to decrease travel costs in comparison to car-owning low-income households. Our results also indicate that on average, urban residents are more likely to travel actively to reduce expenses compared to suburban and rural residents. The lowest spatial variation is found for carless low-income households, demonstrating their higher disadvantage compared to those with cars. Low-income people of color are more likely to use active travel to save money while being a female, older, or having children are attributes associated with a lower probability to use active travel to reduce travel expenses in low-income households.}, journal={INTERNATIONAL JOURNAL OF SUSTAINABLE TRANSPORTATION}, author={Ghimire, Subid and Bardaka, Eleni}, year={2024}, month={Apr} }
 @article{ghimire_bardaka_2023, title={Active travel among carless and car-owning low-income populations in the United States}, volume={117}, ISSN={["1879-2340"]}, url={https://doi.org/10.1016/j.trd.2023.103627}, DOI={10.1016/j.trd.2023.103627}, abstractNote={Low-income households may resort to cycling and walking to alleviate travel costs. Using data from the 2001, 2009, and 2017 National Household Travel Surveys, this study examines the spatiotemporal differences in the use of active travel among three socioeconomic groups classified based on household income and vehicle ownership. After controlling for a number of observed and unobserved factors, we find that individuals in low-income, car-owning households are associated with up to 14% more walking trips and 33% more cycling trips in a week compared to higher-income households, on average. However, in urban areas, higher-income households use active travel significantly more than low-income, car-owning households, while the opposite holds for suburban and rural areas. Individuals living in low-income, carless households are associated with even higher use of active travel. These results suggest that active travel is used, to some extent, out of necessity and lack of other viable options.}, journal={TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT}, author={Ghimire, Subid and Bardaka, Eleni}, year={2023}, month={Apr} }
 @article{gini coefficient: a measure of travel time reliability?_2023, url={https://publons.com/wos-op/publon/54196227/}, DOI={10.2139/SSRN.4367344}, abstractNote={This study examines if the Gini coefficient, which is a widely used measure of income/wealth inequality in a country/society, could be used as a measure of travel time reliability. To be considered a valid measure of travel time reliability, the Gini coefficient should at least agree with existing and widely used reliability measures. We study if the Gini coefficient is in alignment with existing reliability measures by examining the degree to which it correlates with the established measures. Since travel times generally follow right-skewed distributions, we simulate the parameters of four right-skewed distributions: i.log-normal, ii. burr, iii. gamma, and iv. Weibull distributions following which we compute the existing reliability measures as well as the Gini coefficient for each of the parameters. We then compute the correlation coefficients between the Gini coefficient and other established reliability measures. We find that the Gini coefficient is strongly correlated with travel time reliability measures like Buffer-Index, Coefficient of Variation, Width and Skewness for Log-Normal and Gamma distribution. Finally, we test our hypothesis on a travel time data collected using Bluetooth detectors. We perform K-means clustering to segregate the travel rates from the data into two clusters. After determining the suitable distribution for travel rates in each cluster, we compute the Gini coefficient and other reliability measures based on the parameters of the fitted distributions. This study shows that not only does the Gini coefficient agree with existing reliability measures for some distributions, it also helps in intuitively discerning and communicating travel time reliability.}, journal={SSRN Electronic Journal}, year={2023} }
 @article{ghimire_bardaka_monast_wang_wright_2024, title={Policy, management, and operation practices in US microtransit systems}, volume={145}, ISSN={["1879-310X"]}, url={https://doi.org/10.1016/j.tranpol.2023.10.011}, DOI={10.1016/j.tranpol.2023.10.011}, abstractNote={This paper identifies the current practices and challenges related to the planning, management, and operation of microtransit systems as well as the concerns associated with the (lack of) policies in place. Our work focuses on the U.S. experience and is primarily based on an in-depth analysis of six microtransit systems using a combination of quantitative and qualitative data. We investigate and classify the multiple ways public agencies form public-private partnerships to institute microtransit service in their jurisdictions and discuss the relative advantages and disadvantages of the different service delivery models. We also thoroughly examine the contracts public agencies formed with private entities to disentangle the various cost elements associated with the launch and operation of a microtransit system. Our policy discussion emphasizes the lack of sustained funding sources for microtransit and the funding formulas that lead to a reduction or loss of public transportation funding when a jurisdiction replaces a fixed route service with microtransit. We also explain the requirements for ADA compliance in microtransit systems and highlight that service equivalency between disabled and non-disabled riders is not guaranteed when only some of the microtransit vehicles and operators are ADA compliant and certified. In terms of operation practices, we describe the safety risks that microtransit users may face on a day-to-day basis due to algorithm-driven virtual pick-up and drop-off locations, and the unwillingness of some service providers to enforce inclusive practices and ensure that individuals without electronic payment options and smartphones can gain access to the service. Furthermore, we discuss the challenges with balancing supply and demand in microtransit systems, and the need for allowing for both on-demand and pre-scheduled trip requests in order to ensure that critical and time-sensitive work, school, and medical trips are accommodated and prioritized.}, journal={TRANSPORT POLICY}, author={Ghimire, Subid and Bardaka, Eleni and Monast, Kai and Wang, Juan and Wright, Waugh}, year={2024}, month={Jan}, pages={259–278} }
 @article{mechanical properties of concrete with partial replacement of coarse aggregates by coconut shells and reinforced with coconut fibre, url={https://publons.com/wos-op/publon/63005663/}, DOI={10.34118/JBMS.V5I2.61}, abstractNote={This paper centers around the study of physical and mechanical properties of concrete reinforced with coconut fibre and the coarse aggregates of which are partially replaced with coconut shells. American Concrete Institute (ACI) method has been used to design M20 concrete wherein coconut shells (CS) replaced the coarse aggregates (CA) by 6%, 8%, 10%, 12% and 14% by volume. Under each replacement of CA by CS, coconut fibres were added by 3%, 4% and 5% of cement content. Compressive strength of concrete was found to comply with characteristic strength for certain mixes which avers that the replacements were justifiable for concrete production and thus, the optimum mix for the concrete prepared thereby, would have to be considered accentuating the tensile strength which was actually the one with 10% replacement of CA by CS in terms of volume and 3% addition of coconut fibre. The research vividly evinces a decrease in overall density of the concrete thus prepared. The authors suggest the use of coconut shell and fibre in the production of concrete not only because they impart themselves as viable materials, but their use would also assist to abate the amount of environmental waste.} }