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Problem, research strategy, and findingsCovid-19 significantly altered work, out-of-home activity participation, and travel, with much activity time being moved into the home. If these patterns hold, they could imply significant long-term changes for homes, businesses, cities, and transportation. We examined data for 34,000 respondents to the American Time Use Survey from 2019 (the pre-pandemic period), 2021 (the pandemic period), and 2022 and 2023 (the post-pandemic period). We used ordinary least squares (OLS) regressions to study participation in 12 out-of-home activities, travel (by auto, transit, and walking), and 16 in-home activities. We observed sharp declines in overall out-of-home activity, travel by all modes, and 10 of the 12 specific out-of-home activities in 2021 compared with 2019, whereas time spent on 13 of the 16 in-home activities rose during that period. By 2023, most of these changes persisted: Time spent out-of-home, traveling by all modes, and on six out-of-home activities remained notably lower in 2023 than in 2019, whereas time spent on nine in-home activities remained higher. The trend away from out-of-home activities and travel appears to be persisting.Takeaways for practiceFirst, given elevated remote work and shopping, planners should consider repurposing some office and retail land uses. Second, with fewer office workers, center cities may have to capitalize on other strengths such as recreational and residential desirability for some market segments, such as young people or others who prefer urban living. Third, more time at home may increase demand for more spacious and affordable housing, perhaps in lower-cost outlying suburbs of large metros and in smaller metropolitan areas. Finally, an end to ever-rising personal travel may lessen the need for costly interventions to increase the capacity of highway and transportation systems.

Many methods exist for engaging experts in interactive groups to explore, clarify, and/or decide on various issues. In an investigation of four possible future scenarios concerning transportation and land use in California, we developed a novel “hybrid policy Delphi” method for use with a panel of 18 experts. We applied it to explore the policies and practices that would likely lead to each of the four scenarios and the consequences that would result from them. Through our process, panel members discussed and reflected on the scenarios in multiple ways. The scenario they considered most desirable they also deemed least likely to occur, and they foresaw the likely trajectory of California transportation and land use leading to less desirable scenarios. Our mix of discussion and questionnaires traded the benefit of anonymity for the benefit of exploratory, interactive discussion. In addition, our use of surveys before and after meetings allowed us to track changes in panel opinion on a central question and discuss the survey results at meetings, at the cost of greater administrative effort. We discuss the results of this hybrid policy Delphi approach, reflect on how it worked, and conclude with a discussion of limitations and future directions.

Daily vehicle travel collapsed with the onset of the COVID-19 pandemic in early 2020 but largely bounced back by late 2021. The pandemic caused dramatic changes to working, schooling, shopping, and leisure activities, and to the travel associated with them. Several of these changes have so far proven enduring. So, while overall vehicle travel had largely returned to pre-pandemic levels by late 2021, the underlying drivers of this travel have likely changed.To examine one element of this issue, we analyzed whether patterns of daily trip-making shifted temporally between the fall of 2019 and 2021 in the Greater Los Angeles megaregion. We used location-based service data to examine vehicle trip originations for each hour of the day at the U.S. census block group level in October 2019 and October 2021. We observed notable shifts in the timing of post-pandemic PM peak travel, so we examined changes in the ratio of mid-week trips originating in the early afternoon (12–3:59 PM) and the late afternoon/early evening (4–7:59 PM).We found a clear shift in the temporal distribution of PM trip-making, with relatively more late PM peak period trip-making prior to the pandemic, and more early PM peak trip-making in 2021. The peak afternoon/evening trip-making hour shifted from 5–5:59 PM to 3–3:59 PM. We also found that afternoon/evening trip-making in each year is largely explained by three workplace-area/school-area factors: (1) the number of schoolchildren in a block group (earlier); (2) block groups with large shares of potential remote workers (earlier), and (3) block groups with large shares of low-wage jobs and workers of color (later, except for Black workers in 2021). We found the earlier shift in PM peak travel between pre- and late-pandemic periods to be explained most by (1) higher shares of potential remote workers and (2) higher shares of low-wage jobs and workers of color. These findings suggest that the rise of working from home has likely led to a shift in PM peak travel earlier in the afternoon when school chauffeuring trips are most common. This is especially true for low-income workers and workers of color.

Cities nationwide have adopted so-called road diets to improve traffic safety, though they are sometimes met with intense opposition from motorists who fear that road diets will increase traffic delays. Road diets typically convert four-lane roadways with no left-turn lanes into streets with a center left-turn lane, two through-traffic lanes, and (often) bicycle lanes and right turn pockets at intersections. The resulting safety improvements are often dramatic. The Federal Highway Administration currently recommends that road diets should be applied to roadways with fewer than 20,000 average daily trips, but that cities should carefully consider whether to apply road diets above 20,000 average daily traffic (ADT). However, study of higher-traffic-volume road diets to inform decisions about them has been limited. In particular, there is scant evidence that safety benefits erode and traffic delays increase meaningfully above this threshold, though this is implied by the 20,000-ADT threshold. To address this literature gap, we examined the safety and traffic outcomes of high-traffic-volume road diets in Los Angeles, CA. To do this, we compared collisions on five high-traffic-volume road diet corridors with 16 similar multilane, untreated street segments. We found that collisions, injuries, and deaths were lower by 31.2% to 100%, depending on the measure, whereas traffic speeds were lower by about 6.7% (peak) to 7.9% (off-peak). We concluded that in Los Angeles higher-traffic-volume road diets appeared to significantly increase safety with only minor effects on traffic speeds.

The valorization and dissolution of lignin using ionic liquids (ILs) is critical for developing sustainable biorefineries and a circular bioeconomy. This review aims to critically assess the current state of computational and machine learning methods for understanding and optimizing IL-based lignin dissolution and valorization processes reported since 2022. The paper examines various computational approaches, from quantum chemistry to machine learning, highlighting their strengths, limitations, and recent advances in predicting and optimizing lignin-IL interactions. Key themes include the challenges in accurately modeling lignin's complex structure, the development of efficient screening methodologies for ionic liquids to enhance lignin dissolution and valorization processes, and the integration of machine learning with quantum calculations. These computational advances will drive progress in IL-based lignin valorization by providing deeper molecular-level insights and facilitating the rapid screening of novel IL-lignin systems.

Introduction: Several studies have attempted to demonstrate that the Thrombolysis in Myocardial Infarction (TIMI) risk score has the ability to risk stratify emergency department (ED) patients with potential acute coronary syndromes (ACS). Most of the studies we reviewed relied on trained research investigators to determine TIMI risk scores rather than ED providers functioning in their normal work capacity. We assessed whether TIMI risk scores obtained by ED providers in the setting of a busy ED differed from those obtained by trained research investigators. Methods: This was an ED-based prospective observational cohort study comparing TIMI scores obtained by 49 ED providers admitting patients to an ED chest pain unit (CPU) to scores generated by a team of trained research investigators. We examined provider type, patient gender, and TIMI elements for their effects on TIMI risk score discrepancy. Results: Of the 501 adult patients enrolled in the study, 29.3% of TIMI risk scores determined by ED providers and trained research investigators were generated using identical TIMI risk score variables. In our low-risk population the majority of TIMI risk score differences were small; however, 12% of TIMI risk scores differed by two or more points. Conclusion: TIMI risk scores determined by ED providers in the setting of a busy ED frequently differ from scores generated by trained research investigators who complete them while not under the same pressure of an ED provider. [West J Emerg Med. 2015;16(1):24–33.]

To-date, the Brazilian education system does not foresee using the Individualized Education Plan (IEP) for students with disabilities (SWDs) enrolled in general schools. Given the current lack-of national guidelines in this sense, this research sought to analyse the collaborative construction process and-the applicability of the IEP in the physical education (PE) context. Specifically, it aimed to elucidate the consequences of the optional (non-mandatory) implementation of the IEP in PE classes. Based on a qualitative and descriptive approach, collaborative research was established involving a partnership among researchers and physical education teachers (PETs), to support the inclusion of SWDs in PE classes. The study was conducted in two public schools in a district of São-Paulo, Brazil. The content analysis resulted in five categories: previous knowledge about the IEP-PE by the PETs; insufficiency in PETs' initial training; changes in the perception and attitudes of PETs towards SWDs; the influence of IEP-PE on teaching program and pedagogical practices; and difficulties in constructing and applying the IEP-PE. In conclusion, the IEP-PE consists of-a pedagogical tool to help PETs identify the limitations and potentialities of SWDs. It-also supports adjustments in the curriculum and implementation of adaptations in PE classes, favoring the inclusion of SWDs in-this context.

The COVID-19 pandemic upended transit use, finance, and management. To investigate these effects two years into the pandemic, we conducted 21 semi-structured interviews with senior managers at transit agencies in the most populous U.S. state, California. We found that the pandemic generated many operational and managerial challenges for transit agencies. Ridership plummeted, then slowly recovered, but is still well below pre-pandemic levels at most agencies. Commuter trips to and from major job centers were especially slow to return. In response to decreased demand, public health concerns, and uncertain finances, many agencies cut services and spending early on. As a result, fare revenues declined, in some cases precipitously. However, federal pandemic relief funds proved essential in filling budgetary gaps, stabilizing finances, preventing layoffs, and maintaining services. Other transit subsidies mostly bounced back robustly. Our interviews suggest that, though California transit agencies experimented with free fares, few fareless programs were made permanent. Their challenges include considerable uncertainty associated with future travel demand, looming financial shortfalls at systems that formerly had high farebox recovery and are still drawing on federal pandemic funds to backfill their fare revenue losses, and protracted labor shortages of drivers and mechanics that are preventing many systems from providing desired levels of service.

Peaking on public transit—the concentration of ridership in peak times and directions into and out of central areas—has waxed in the U.S. over the past century, as public transit has lost more mode share at off-peak times, in off-peak directions, and among non-commute trips. A notable pre-pandemic manifestation of this chronic problem was on Bay Area Rapid Transit, the San Francisco Bay Area’s regional heavy rail system. While BART staved off an absolute ridership decline longer than most American transit operators in the mid- and late-2010s, it did so almost entirely due to peak gains in riders offsetting off-peak losses. As a result, the system experienced worsening passenger crowding at some times and places, expanding underutilization of capacity at many others, and the prospect of enormous expenditures to accommodate rising transbay passenger demand. To examine the factors driving transit use in the 2010s, we model peak and off-peak BART trips as a function of station area and system characteristics. We uniquely use origin–destination pairs as the unit of analysis in order to separately measure influences at both ends of the trip. We find that transfers and travel time most influence peak and off-peak BART ridership and that station-area employment and time-competitiveness with driving particularly influence peak patronage. Over time in our models, the associations between ridership and transit travel time weakened, while the associations between ridership and transfers, employment, and time-competitiveness with driving grew stronger. In sum, we find that the peaking problem plaguing public transit systems for decades worsened in the years leading up to the pandemic—on this one nationally significant U.S. transit system, at least—which poses potentially substantial financial challenges in the years ahead.

Metabolic cross-feeding plays vital roles in promoting ecological diversity. While some microbes depend on exchanges of essential nutrients for growth, the forces driving the extensive cross-feeding needed to support the coexistence of free-living microbes are poorly understood. Here we characterize bacterial physiology under self-acidification and establish that extensive excretion of key metabolites following growth arrest provides a collaborative, inter-species mechanism of stress resistance. This collaboration occurs not only between species isolated from the same community, but also between unrelated species with complementary (glycolytic vs. gluconeogenic) modes of metabolism. Cultures of such communities progress through distinct phases of growth-dilution cycles, comprising of exponential growth, acidification-triggered growth arrest, collaborative deacidification, and growth recovery, with each phase involving different combinations of physiological states of individual species. Our findings challenge the steady-state view of ecosystems commonly portrayed in ecological models, offering an alternative dynamical view based on growth advantages of complementary species in different phases.

California and its regional and local governments have invested heavily in public transit over the past half-century to provide an alternative to driving, ease traffic congestion, reduce emissions, slow climate change, steer new development, and provide mobility for those without. As a result, bus service has improved and expanded, and many parts of the state’s metropolitan areas are now served by rail transit.Yet today, many of the state’s transit systems are struggling operationally and financially. Ridership began eroding in the half-decade leading up to 2020 and plummeted at the start of the COVID-19 pandemic. Three federal pandemic relief bills provided a critical lifeline to keep struggling transit systems afloat early on, but these funds are running out. Meanwhile, operating costs have risen, ridership and fare revenues have only partially returned, and some transit systems face “fiscal cliffs,” where they will need substantial new infusions of funding, substantial cuts in costs and service, or some combination of the two.Against this backdrop, this report examines the current state of California transit finance: why ridership and fare revenues are down and their prospects for recovery; what lessons the successful federal relief bills provide; why commuter-oriented systems are struggling financially much more than those that primarily service transit-reliant riders; and what the financial managers at transit systems have done to cope with this turbulent time and how they see their future financial prospects.

The COVID-19 pandemic occasioned significant financial distress and uncertainty for many U.S. transit operators. In the face of this crisis, the federal government provided substantial supplemental operating support. To understand how this fiscal turmoil and relief have affected U.S. transit systems, we conducted two nationwide surveys of transit agency staff in 2020 and 2021-2022. While pandemic-induced financial shortfalls affected service in 2020, with capital projects delayed too, these effects became much more muted by 2021/2022. Most systems reported moderate to substantial increases in federal funding during the pandemic, more so than other funding categories. However, nearly half foresee financial shortfalls once federal relief funding expires. Agencies with higher pre-pandemic ridership and farebox recovery are particularly affected by fare revenue losses and more likely to anticipate shortfalls. In the near term, difficulty hiring and retaining front-line workers was a pressing concern, while very few had plans to maintain pandemic fare suspensions.

This research synthesizes literature on the relationship between working from home and travel. This relationship is a pertinent one because transportation planners and policymakers have long hoped that increased remote work, sometimes called telecommuting or telework, will reduce driving, traffic congestion, and vehicle emissions. This question is especially pertinent today because working from home increased dramatically early in the COVID-19 pandemic and has remained at substantially elevated levels since then. To examine this issue, we review nearly 100 research articles, reports, and some popular accounts of telecommuting and travel prior to and during the pandemic. In conducting this review, we arrive at five principal findings. First, remote work increased dramatically with the onset of the pandemic and appears likely to remain elevated for many years to come. Second, while not everyone can work remotely, for those who have the option to do so, at least part-time, this hybrid option is extremely popular with most workers. Third, employers tend to be skeptical of the benefits of remote work, but the research does not support fears of declining productivity in the near term, and the tight post-pandemic labor market has given workers leverage to insist on remote work options. Fourth, telecommuting has long been touted as a potential solution to chronic transportation problems like traffic congestion and vehicle emissions, but the research has consistently found that it is more likely to increase, rather than decrease, overall driving among remote workers. This extra driving is due both to hybrid workers living farther from work, on average, than non-remote workers and to all remote workers making more household-serving and personal trips when they work from home. And fifth, public transit systems, in contrast to street and highway systems, have been dramatically affected by the pandemic, likely due substantially to the rise in remote work it has engendered. The future of many public transit systems, which draw an outsized share of their riders from commuters to downtowns and other major job centers, will depend on whether and to what extent those job centers re-densify with workers in the months and years ahead.

We examine pre-COVID declines in transit ridership, using Southern California as a case study. We first illustrate Southern California's unique position in the transit landscape: it is a large transit market that demographically resembles a small one. We then draw on administrative data, travel diaries, rider surveys, accessibility indices, and Census microdata for Southern California, and demonstrate a strong association between rising private vehicle access, particularly among the populations most likely to ride transit, and falling transit use. Because we cannot control quantitatively for the endogeneity between vehicle acquisition and transit use, our results are not causal. Nevertheless, the results strongly suggest that increasing private vehicle access helped depress transit ridership. Given Southern California's similarity to most US transit markets, we conclude that vehicle access may have played a role in transit losses across the US since 2000.

Transit ridership plummeted at the onset of the COVID-19 pandemic, and what constituted passenger crowding contracted dramatically as well. We examine trends in average passenger loads and their correlates in a national sample of U.S. transit operators during the first year of the pandemic and find that passenger loads in high-transit-ridership areas and on the largest systems fell the most early on. Passenger loads were actually somewhat more likely to increase in places where COVID-19 rates were higher during the first year of the pandemic, which suggests that pandemic transit riders had fewer options to travel by other means.

In this report, we examine both the substantial research literature on transit pricing and use and literature on free- and reduced fare (FAR) programs. In general, we find that FAR programs can take many forms, and the idea of “fare-free” transit is far from a one-size-fits-all proposition. Second, while reducing or eliminating fares does indeed increase ridership, all else equal, transit research has consistently found that riders tend to be more service elastic than fare elastic. In other words, they tend to respond more to service improvements than price reductions, which means that, at the margin, money “spent” on fare-free programs (in the form of foregone revenues) may attract fewer riders than if that money were put toward improving service. And third, the social equity dimensions of fare-free transit are many, ranging from considering the share of fare-free benefits that flow to higher-income riders to the potential racial equity benefits of reduced fare enforcement policing on transit.

The COVID-19 pandemic dramatically affected public transit systems around the globe. Because transit systems typically move many people closely together on buses and trains, public health guidance demanded that riders should keep a distance of about two meters to others changed the definition of crowding on transit in 2020. Accordingly, this research examines how U.S. public transit agencies responded to public health guidance that directly conflicted with their business model. To do this, we examined published crowding standards before the COVID-19 pandemic for a representative sample of 200 transit systems, including whether they started or changed their published standards during the pandemic, as well as the reasons whether agencies publicize such standards at all. We present both descriptive statistics and regression model results to shed light on the factors associated with agency crowding standards. We find that 56% of the agencies surveyed published crowding standards before the pandemic, while only 46% published COVID-19-specific crowding standards. Regression analyses suggest that larger agencies were more likely to publish crowding standards before and during the COVID-19 pandemic, likely because they are more apt to experience crowding. Pandemic-specific crowding standards, by contrast, were associated with a more complex set of factors. We conclude that the relative lack of pandemic standards reflects the uncertainty and fluidity of the public health crisis, inconsistent and at times conflicting with the guidance from public health officials, and, in the U.S., a lack national or transit industry consensus on appropriate crowding standards during the first year of the pandemic.

Public investment in transit increased following the Great Recession, yet transit use nationally mostly fell, even prior to the 2020 pandemic. We investigate this troubling disjuncture by comparing transit ridership trends during the 2010s in two of America’s largest regions: Greater Los Angeles and the San Francisco Bay Area. While both California regions lost transit riders, we see substantial differences in the scale, timing, geography, and modes of these declines. In the LA area, ridership fell longer and further, spread more across routes, times, and sub-regions and concentrated on the region’s dominant operator. In both regions, increasing auto access appears to have played a central role, albeit in different ways. Greater LA saw increased automobile ownership, particularly among high-propensity transit riders. In the Bay Area, as jobs and housing have dispersed, ridehail services like Lyft and Uber may have eroded non-commute transit use.

UNLABELLED: While the COVID-19 pandemic upended many aspects of life as we knew it, its effects on U.S. public transit were especially dramatic. Many former transit commuters began to work from home or switched to traveling via private vehicles. But for those who continued to work outside the home and could not drive-who were more likely low-income and Black or Hispanic-transit remained an important means of mobility. However, most transit agencies reduced service during the first year of the pandemic, reflecting reduced ridership demand, increasing costs, and uncertain budgets. To analyze the effects of the pandemic on transit systems and their users, we examine bus ridership changes by neighborhood in Boston, Houston, and Los Angeles from 2019 to 2020. Combining aggregated stop-level boarding data, passenger surveys, and census data, we identify associations between shifting travel patterns and neighborhoods. We find that early in the pandemic, neighborhoods with more poor and non-white households lost proportionally fewer riders; however, this gap between high- and low-ridership-loss neighborhoods shrank as the pandemic wore on. We also model ridership change controlling for multiple factors. Ridership in Houston and LA generally outperformed Boston, with built environment and demographic factors accounting for some of the observed differences. Neighborhoods with high shares of Hispanic and African American residents retained more riders in the pandemic, while those with higher levels of auto access and with more workers able to work from home lost more riders, all else equal. We conclude that transits social service role elevated during the pandemic, and that serving travelers in disadvantaged neighborhoods will likely remain paramount emerging from it. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11116-022-10345-1.

To investigate possible future transportation and land use scenarios for California as well as their likely precipitating policies and potential consequences, we convened a panel of 18 experts and used a novel variation of the Delphi method to systematically explore four specific scenarios and probe the desirability and likelihood of each. The scenario that panel members collectively thought most desirable for California (one with diverse transportation options and higher-density development) was also the one they thought least likely to materialize by 2050. This report describes the findings of the three surveys and two meetings that our method entailed and summarizes some of the discussion among panelists. We include reflections on the salient but unexpected finding that panelists viewed trust in government as both critical to effecting the scenario they considered most desirable and also lacking to such an extent that pursuing that desirable outcome could cause unintended consequences or outright failure. Accordingly, we discuss possible implications and outline policy recommendations for improving both processes and conditions that can instill in California’s government more trust, without which a future of multimodal transportation and higher-density, mixed land uses is unlikely to succeed.