Transport Time Research Articles

Effect of urgency level on prehospital emergency transport times: a natural experiment.

Accurate estimation of ambulance transport time from the scene of incident to arrival at the emergency department (ED) is important for effective resource management and emergency care system planning. Further, differences in transport times between different urgency levels highlight the benefits of ambulance transports with highest urgency level in a setting where ambulances are allowed to not follow standard traffic rules. The objective of the study is to compare ambulance urgency level on the differences in estimates of ambulance transport times generated by Google Maps and the observed transport times in a prehospital setting where emergency vehicles have their own traffic laws. The study was designed as a natural experiment and register study. Ambulance transports dispatched with different levels of urgency (Level A and B) were included in the Central Denmark Region (a mixed urban and rural area) from March 10 to June 11, 2021. Ambulance transports for highest urgency level were compared to lowest urgency level with Google Maps estimated transport times as reference. We analyzed 1981 highest urgency level and 8.958 lowest urgency level ambulance transports. Google Maps significantly overestimated the duration of transports operating at highest level of urgency(Level A) by 1.9min/10km (95% CI 1.8; 2.0) in average and 4.8min/10km (95% CI 3.9; 5.6) for the first driven 10km. Contrary, Google Maps significantly underestimated the duration of transports operating at lowest level of urgency (Level B)by -1.8min/10km (95% CI -2.1; -1.5) in average and -4.4min/10km (95% CI -5.4; -3.5) for the first driven 10km. Google Maps systematically overestimates transport times of ambulance transports driven with Level A, the highest level of urgency in a setting where ambulances are allowed to not follow standard traffic rules. The results highlight the benefit of using urgency Level A and provide valuable information for emergency care management.

Eating Quality of Australian Grass and Grain-Fed Lamb Equally Rated by US Consumers.

Anecdotal suggestions that US consumers perceive Australian sheepmeat as more "gamey" or "stale" compared to US sheepmeat are potentially attributable to the extended chilled shipping times contributing to longer-aged meat and predominately pasture-fed grazing systems. This study evaluated the impact of diet and extended storage times on Australian sheepmeat using sensory scores as assessed by US consumers. Meat samples from Australian sheep (n = 80) fed a grass or grain diet were aged in a vacuum at 1-2 °C for 5, 21 or 45 days. Untrained consumers (n = 960) at Texas Tech University (Lubbock, Texas) assessed samples for overall liking, tenderness, juiciness and flavour using a scale from 1 (worst) to 100 (best). In general, US consumers scored grain- and grass-fed samples within the same storage period similarly (p > 0.05). Furthermore, storage from 5 to 21 days improved sensory scores by a maximum of 28.6 for tenderness for grass-fed outside cuts (p < 0.05), while storage for 21 to 45 days did not improve eating quality for most cuts of both diets (p > 0.05). This is an interesting finding for the Australian sheepmeat industry as long storage time has no negative effect on eating quality and US consumers enjoyed grass- and grain-fed sheepmeat equally.

A critical time window for leukapheresis product transportation to manufacture clinical-grade dendritic cells with optimal anti-tumor activities

Background aimsDendritic cell (DC)-based immunotherapy is a promising approach to treat cancer. However, key aspects governing the reproducible manufacturing of high-quality DC remain incompletely defined. Here, we show that the time window between leukapheresis and DC manufacturing is critical. MethodsTranscriptomic profiling by RNA-seq was used to unbiasedly characterize cellular states during each step of DC manufacturing process, and functional assays were used to determine the anti-tumor activities of DC. ResultsDuring preclinical development of a DC-based cytotherapy platform, CUD-002 (NCT05270720), we found that DC quality varied among different batches, even though commonly used DC maturation markers CD80, CD83 and CD86 were indistinguishable. Multivariate analysis indicated that DC quality was negatively associated with the shipping time from the leukapheresis site to the manufacturing center. To investigate the potential effect of shipping time, we stored leukapheresis materials from three donors for 0, 1, 2 or 3 days before DC manufacturing. For each step, we carried out RNA-seq analysis to unbiasedly characterize cellular states. Integrated bioinformatic analyses indicated that longer storage time reduced the expression of several transcription factors to attenuate interferon pathways. ConclusionsConsistently, we found that 3-day storage of leukapheresis materials significantly lowered the efficiency to generate DC but also impaired DC responses to inflammatory signals, resulting in inferior antigen-presentation and cytotoxic T-cell activities. Thus, we recommend using leukapheresis materials within 48 h to manufacture therapeutic DCs.

Особливості сучасного управління судноплавною компанією

Methods of planning and management in the maritime transport system require a reflection of the peculiarities of the activities of subsystems of the maritime transport industry. In this regard, planning of investment activities should be considered as a guarantee of maintaining or expanding the company's position in the global trade market. An important aspect in the development of maritime transport enterprises is the establishment of effective partnerships with other companies and the development of intermodal transportation systems. This requires the introduction of innovative technologies that increase the efficiency of logistics processes and reduce the time and cost of cargo transportation. The creation of strategic alliances between companies is also important for building competitive advantages and expanding the geographical coverage of cargo transportation.

Determining the optimal time interval between sample acquisition and cryopreservation when processing immature testicular tissue to preserve fertility

The cryopreservation of immature testicular tissue (ITT) prior to gonadotoxic therapy is crucial for fertility preservation in prepubertal boys with cancer. However, the optimal holding time between tissue collection and cryopreservation has yet to be elucidated. Using the bovine model, we investigated four holding times (1, 6, 24, and 48 h) for ITTs before cryopreservation. Biopsies from two-week-old calves were stored in transport medium and cryopreserved following a standard slow-freezing clinical protocol. Thawed samples were then assessed for viability, morphology, and gene expression by haematoxylin and eosin (H&E) staining, immunohistochemistry and real-time quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Analysis failed to identify any significant changes in cell viability when compared between the different groups. Sertoli (Vimentin+) and proliferating cells (Ki67+) were well-preserved. The expression of genes related to germ cells, spermatogenesis (STRA8, PLZF, GFRα-1, C-KIT, THY1, UCHL-1, NANOG, OCT-4, CREM), and apoptosis (HSP70-2) remained stable over 48 h. However, seminiferous cord detachment increased significantly in the 48-h group (p < 0.05), with associated cord and SSC shrinkage. Collectively, our analyses indicate that bovine ITTs can be stored for up to 48 h prior to cryopreservation with no impact on cell viability and the expression levels of key genes. However, to preserve the morphology of frozen-thawed tissue, the ideal processing time would be within 24 h. Testicular tissues obtained from patients for fertility preservation often need to be transported over long distances to be cryopreserved in specialist centres. Our findings highlight the importance of determining optimal tissue transport times to ensure tissue quality in cryopreservation.

Study of time indicators of public transport operation depending on the season of the year

Mobility problems in large cities of Ukraine and Eastern Europe are complicated by the fact that the increase of private transport volume significantly exceeds street and road network`s capacity. This is most noticeable during peak periods in terms of daylight hours and throughout the year. From the point of sustainable mobility view, this negative phenomenon significantly affects urban public transport, which does not have separate dedicated traffic lines. This article analyzes the issue regarding the deterioration of the transport situation in large cities. The reason for this is the increase in traffic on main streets during the day peaks, as well as the presence of seasonal traffic factors. If the issue of the occurrence and traffic jams duration and the increase in the correspondence time of private transport is sufficiently studied, then the problems of changing the schedules of public transport and taking into account the increase in the trip duration depending on the time of year need to be clarified. The routes of public transport, which do not have a separate infrastructure and move in the general flow together with private cars, were chosen for the study. According to the results of remote monitoring of public transport, a change in the trip duration and time lost due to the boarding and disembarking of passengers on similar trolleybus routes in different seasons was established. Based on the obtained data, a matrix of trip duration unevenness coefficients for public transport routes was formed, and a measure of the seasonality effect on these indicators was established. The obtained results make it possible to quantitatively determine the influence of the season and time of the day on the change in the trip duration, which can be applied in further studies using simulation tools and for practical use in drawing up seasonal traffic schedules. The results of the research complement the currently relevant scientific works, which concern the problems of seasonal mobility, as well as the influence of the social infrastructure objects functioning (schools, kindergartens, and other educational institutions) of cities on the peak load of the street and road network, which extends the duration of traffic not only for private but also public transport.

Fuzzy Programming Approach to Solve Multi-Objective Fully Fuzzy Transportation Problem

The aim of this study is presenting the solution methodology of multi-objective fuzzy transportation problem with fuzzy decision variables, where all the input parameters and decisions variables of the programming problems are assumed to be triangular fuzzy number and triangular fuzzy decision variables respectively. Moreover the objectives under considerations are minimization of cost of transportation and minimization of shipping time under fuzzy environment. The fuzziness of the objective functions and the fuzzy constraints of the programming problem are defuzzified using the ranking function and the equality property between two fuzzy numbers, respectively. The consequent crisp multi-objective fuzzy transportation problem is tackled by employing fuzzy mathematical programming approach. Finally fuzzy decision is made after solving the resultant mathematical programming problem using LINGO(Schrage and LINDO Systems (1997)) software. Illustrative numerical example is presented in support of the proposed methodology.

Spatiotemporal Observation of Quasi-Ballistic Transport of Electrons in Graphene.

We report spatiotemporal observations of room-temperature quasi-ballistic electron transport in graphene, which is achieved by utilizing a four-layer van der Waals heterostructure to generate free charge carriers. The heterostructure is formed by sandwiching a MoS2 and MoSe2 heterobilayer between two graphene monolayers. Transient absorption measurements reveal that the electrons and holes separated by the type-II interface between MoS2 and MoSe2 can transfer to the two graphene layers, respectively. Transient absorption microscopy measurements, with high spatial and temporal resolution, reveal that while the holes in one graphene layer undergo a classical diffusion process with a large diffusion coefficient of 65 cm2 s-1 and a charge mobility of 5000 cm2 V-1 s-1, the electrons in the other graphene layer exhibit a quasi-ballistic transport feature, with a ballistic transport time of 20 ps and a speed of 22 km s-1, respectively. The different in-plane transport properties confirm that electrons and holes move independently of each other as charge carriers. The optical generation of ballistic charge carriers suggests potential applications for such van der Waals heterostructures as optoelectronic materials.

Nanoscale Energy Transport Dynamics across Nonbonded Solid-Molecule Interfaces and in Molecular Thin Films.

Thermal conductance across a solid-solid interface requires an atomic- or molecular-level understanding, especially when a system is in a non-equilibrium state and/or consists of nanosized materials with prominent differences in structures, properties, and vibrational behaviors. Here, we report the lattice dynamics of graphite-supported molecular thin films of ethanol, whose layers exhibit in-plane hydrogen-bonded chains and out-of-plane van der Waals stacking with clear structural anisotropy. The direct structure-probing method of ultrafast electron diffraction reveals a surprising temperature difference of more than 400 K at pico- to sub-nanosecond times across the graphite-ethanol interface, yet the temporal behavior signifies a reasonably large thermal boundary conductance. This apparent conflict in a non-equilibrium condition can be resolved by considering the coupling of out-of-plane motions, instead of the commonly used temperature-based model, at transient times for energy transport across the interface separated by van der Waals interactions with mismatched unit sizes and no strong bonds. The importance of spatiotemporally resolved structural dynamics at the atomic or molecular level is emphasized.

Influence of pneumatic transportation on the stability of monoclonal antibodies

Pneumatic transportation systems (PTS) were recently proposed as a method to carry ready-for-injection diluted monoclonal antibodies (mAbs) from the pharmacy to the bedside of patients. This method reduces transportation time and improves the efficiency of drug distribution process. However, mAbs are highly sensitive molecules for which subtle alterations may lead to deleterious clinical effects. These alterations can be caused by various external factors such as temperature, pH, pressure, and mechanical forces that may occur during transportation. Hence, it is essential to ensure that the mAbs transported by PTS remain stable and active throughout the transportation process. This study aims to determine the safety profile of PTS to transport 11 routinely used mAbs in a clinical setting through assessment of critical quality attributes (CQA) and orthogonal analysis. Hence, we performed aggregation/degradation profiling, post-translational modifications identification using complementary mass spectrometry-based methods, along with visible and subvisible particle formation determination by light absorbance and light obscuration analysis. Altogether, these results highlight that PTS can be safely used for this purpose when air is removed from the bags during preparation.

Two-machine job-shop scheduling with one joint job

In this research, we consider a two-machine job-shop scheduling problem with one joint job where a joint job is defined as a job whose operations are to be processed by different machines. The machine repetition and transportation times between machines are also considered. This problem is associated with real-world applications in the fields of production planning and supply chains. We first demonstrate that this problem is NP-hard in the strong sense. We then propose polynomial-time algorithms based on dynamic programming for cases with a fixed number of jobs. We also propose lemmas to reduce the number of states in dynamic programming without loss of optimality, so that the time complexity is improved. Other methodologies, including preprocessing and the two-pointers method, are also embedded to improve the algorithms. The proposed algorithms have better time complexities than those of variants of a well-known algorithm when applied to the cases of our problem.

Classical and quantum elliptical billiards: Mixed phase space and short-range correlations in singlets and doublets

Billiards are flat cavities where a particle is free to move between elastic collisions with the boundary. In chaos theory, these systems are simple prototypes. The conservative dynamics of a billiard may vary from regular to chaotic, depending only on the shape of the boundary. This work aims to shed light into the quantization of classically chaotic systems. We present numerical results on classical and quantum properties in two bi-parametric families of billiards, namely Elliptical Stadium Billiard (ESB) and Elliptical-C3 Billiards (E-C3B). Both families entail elliptical perturbations of chaotic billiards with originally circular sectors on their borders. Our numerical calculations provide evidence that these elliptical families may exhibit a mixed classical dynamics, identified by the chaotic fraction of the phase space, the parameter χc<1. We use this quantity to guide our analysis of quantum spectra. We explore the short-range correlations through nearest neighbor spacing distribution p(s), revealing that in the mixed region of the classical phase space, p(s) is well described by the Berry–Robnik–Brody (BRB) distributions for the ESB. In agreement with the expectation from the so-called ergodic parameter α=tH/tT, the ratio between the Heisenberg time and the classical diffusive-like transport time. Our findings indicate the possibility of quantum dynamical localization when α<1. For the E-C3B family, the eigenstates can be split into singlets and doublets. BRB successfully describes p(s) for singlets as the previous family in the mixed region. However, for doublets, new distributions recently introduced in the literature come into play, providing descriptions for p(s) with a focus on cases where χc=1. We observed that as χc decreases, the p(s) distributions simultaneously deviate from the Gaussian Orthogonal Ensemble (GOE) for singlets, and Gaussian Unitary Ensemble (GUE) for doublets.

Quantitative perfusion and water transport time model from multi b-value diffusion magnetic resonance imaging validated against neutron capture microspheres.

Quantification of perfusion in ml/100 g/min, rather than comparing relative values side-to-side, is critical at the clinical and research levels for large longitudinal and multi-center trials. Intravoxel incoherent motion (IVIM) is a non-contrast magnetic resonance imaging diffusion-based scan that uses a multitude of -values to measure various speeds of molecular perfusion and diffusion, sidestepping inaccuracy of arterial input functions or bolus kinetics. Questions remain as to the original of the signal and whether IVIM returns quantitative and accurate perfusion in a pathology setting. This study tests a novel method of IVIM perfusion quantification compared with neutron capture microspheres. We derive an expression for the quantification of capillary blood flow in ml/100 g/min by solving the three-dimensional Gaussian probability distribution and defining water transport time (WTT) as when 50% of the original water remains in the tissue of interest. Calculations were verified in a six-subject pre-clinical canine model of normocapnia, induced hypercapnia, and middle cerebral artery occlusion (ischemic stroke) and compared with quantitative microsphere perfusion. Linear regression analysis of IVIM and microsphere perfusion showed agreement (slope = 0.55, intercept = 52.5, ) with a Bland-Altman mean difference of . Linear regression between dynamic susceptibility contrast mean transit time and IVIM WTT asymmetry in infarcted tissue was excellent (, intercept = 0.3, ). Strong linear agreement was found between IVIM and reference standard infarct volume (slope = 1.01, ). The simulation of cerebrospinal fluid (CSF) suppression via inversion recovery returned a blood signal reduced by 82% from combined T1 and T2 effects. The accuracy and sensitivity of IVIM provides evidence that observed signal changes reflect cytotoxic edema and tissue perfusion and can be quantified with WTT. Partial volume contamination of CSF may be better removed during post-processing rather than with inversion recovery.

The Effects of Vibration Frequency on Oxidative Stress, Digestive Enzymes and ATPases of Crimson Snapper (Lutjanus erythropterus) Fry during Transport

In this study, we sought to characterize the effect of water vibration frequency stress on crimson snapper (Lutjanus erythropterus) survival to determine an optimal transportation speed. To achieve this, we used a transport tank (25 cm × 17 cm × 16 cm) to simulate the transport process. After 8 h at five different vibration frequencies (D1 = 75 rpm, D2 = 105 rpm, D3 = 135 rpm, D4 = 165 rpm, and D5 = 195 rpm), the pH and dissolved oxygen (DO) levels in the tanks decreased; ammonia nitrogen levels (NH4-N) and temperature (T) increased with increasing density; and significant changes in oxidative stress biomarkers, digestive enzymes, and ATPase levels were observed in crimson snapper fry. The enzyme activity increased and reached the maximum value at 195 rpm. The experimental results suggested that during the actual transport, when using transport tanks, the length of the transport time was less than 8 h, and setting the vibration frequency for transportation at 135 rpm was more appropriate, that is, a speed of 50 km/h for transporting crimson snapper fry.

The Role of Paramedics in Disclosure of Patient Safety Incidents: A Mixed Methods Study

ObjectiveCritical care transport is a high-risk environment ripe for patient safety incidents (PSIs). Disclosure is the process by which a PSI is communicated to a patient or substitute decision maker. Little is known on paramedic perceptions on disclosure PSIs. This study evaluated the impact of a disclosure training program on the perceptions of paramedics on disclosing PSIs. MethodsThis was a before-and-after mixed methods survey study on paramedic disclosure training at Ornge, the provincial critical care transport organization for Ontario, Canada. A paramedic disclosure training program was implemented at Ornge between 2020 and 2022. All paramedics were eligible for participation through pre- and posttraining surveys. ResultsIn total, 54 and 69 paramedics completed the pretraining and posttraining surveys, respectively, representing 25% to 30% of all active paramedics. All of the paramedics (100%) expressed a moral and professional responsibility to disclose PSIs. All paramedics felt disclosure training was somewhat to extremely useful. After training, more paramedics felt comfortable disclosing PSIs, and more paramedics felt disclosure could occur at the time of transport. ConclusionA training program on PSIs can improve paramedics’ perceptions on disclosure. This study shows its feasible for paramedics to feel comfortable and participate in disclosure of PSIs within a critical care environment.

Giving birth on the way to the clinic: undocumented migrant women’s perceptions and experiences of maternal healthcare accessibility along the Thailand–Myanmar border

BackgroundMillions of women give birth annually without the support of a trained birth attendant. Generally and globally, countries provide maternal health services for their citizens but there is a coverage gap for undocumented migrant women who often can’t access the same care due to their legal status. The objective of this investigation is to explore undocumented migrants’ experiences and perceptions of maternal healthcare accessibility.MethodsWe held focus groups discussions with 64 pregnant women at 3 migrant health clinics on the Thailand–Myanmar border and asked how they learned about the clinic, their health care options, travel and past experiences with birth services. In this context undocumented women could sign up for migrant health insurance at the clinic that would allow them to be referred for tertiary care at government hospitals if needed.ResultsWomen learned about care options through a network approach often relying on information from community members and trusted care providers. For many, choice of alternate care was limited by lack of antenatal care services close to their homes, limited knowledge of other services and inability to pay fees associated with hospital care. Women travelled up to 4 h to get to the clinic by foot, bicycle, tractor, motorcycle or car, sometimes using multiple modes of transport. Journeys from the Myanmar side of the border were sometimes complicated by nighttime border crossing closures, limited transport and heavy rain.ConclusionsUndocumented migrant women in our study experienced a type of conditional or variable accessibility where time of day, transport and weather needed to align with the onset of labour to ensure that they could get to the migrant clinic on time to give birth. We anticipate that undocumented migrants in other countries may also experience conditional accessibility to birth care, especially where travel is necessary due to limited local services. Care providers may improve opportunities for undocumented pregnant women to access maternal care by disseminating information on available services through informal networks and addressing travel barriers through mobile services and other travel supports.Trial registration The research project was approved by Research Ethics Committee at the Faculty of Medicine, Chiang Mai University (FAM-2560-05204), and the Department of Community Medicine and Global Health at the University of Oslo—Norwegian Centre for Research Data (58542).

Analysis of path planning of UAV in short-distance logistics application

China's e-commerce sector has grown quickly in recent years, and the logistics sector has grown to be a significant sector of the national economy. Meanwhile, the business volume of the logistics industry has also increased continuously. The characteristics of intelligence and informatization of short-distance logistics UAVs, advantages such as high efficiency and not being constrained by road grids and related technical applications can greatly save manpower and time in logistics and transportation, so that the goods can be transported to the receiving place faster. Therefore, UAVs are an important part of the logistics field, among them, the path planning of UAVs is an important technical component to ensure the transportation of goods. This article first introduces the importance of UAV path planning technology in the field of short-distance logistics. Secondly, the path planning of UAVs in short-distance logistics applications is divided into two categories. The overview and analysis are carried out from the two aspects of traditional mathematical algorithm and bionic algorithm. Meanwhile, based on the available information, the benefits and drawbacks of the available methods are examined. Then, based on MATLAB, two classical methods are selected from the traditional mathematical algorithm and the bionic algorithm to carry out path planning simulation experiments in scenarios of different complexity, and the results are analyzed. Finally, the advantages and disadvantages of the above two algorithms are summarized and analyzed, and the prospect of UAV citation in short-distance logistics is prospected.

Association between geospatial access to trauma center care and motor vehicle crash mortality in the United States.

Motor vehicle crashes (MVCs) are a leading cause of preventable trauma death in the United States. Access to trauma center care is highly variable nationwide. The objective of this study was to measure the association between geospatial access to trauma center care and MVC mortality. This was a population-based study of MVC-related deaths that occurred in 3,141 US counties (2017-2020). American College of Surgeons and state-verified Level I to III trauma centers were mapped. Geospatial network analysis estimated the ground transport time to the nearest trauma center from the population-weighted centroid for each county. In this way, the exposure was the predicted access time to trauma center care for each county population. Hierarchical negative binomial regression measured the risk-adjusted association between predicted access time and MVC mortality, adjusting for population demographics, rurality, access to trauma resources, and state traffic safety laws. We identified 92,398 crash fatalities over the 4-year study period. Trauma centers mapped included 217 Level I, 343 Level II, and 495 Level III trauma centers. The median county predicted access time was 47 minutes (interquartile range, 26-71 minutes). Median county MVC mortality was 12.5 deaths/100,000 person-years (interquartile range, 7.4-20.3 deaths/100,000 person-years). After risk-adjustment, longer predicted access times were significantly associated with higher rates of MVC mortality (>60 minutes vs. <15 minutes; mortality rate ratio 1.36; 95% confidence interval, 1.31-1.40). This relationship was significantly more pronounced in urban/suburban vs. rural/wilderness counties ( p for interaction, <0.001). County access to trauma center care explained 16% of observed state-level variation in MVC mortality. Geospatial access to trauma center care is significantly associated with MVC mortality and contributes meaningfully to between-state differences in road traffic deaths. Efforts to improve trauma system organization should prioritize access to trauma center care to minimize crash fatalities. Prognostic and Epidemiological, Level III.

A simulation-based genetic algorithm approach for the simultaneous consideration of reverse logistics network design and disassembly line balancing with sequencing

Reverse logistics (RL) network design and disassembly line balancing (DLB) decisions are generally considered separately. In addition, the effect of disassembly sequencing on DLB is ignored. However, companies can take better-informed decisions by simultaneously considering RL, DLB and disassembly sequencing issues. This integrated approach results in more efficient processes which reduce cost and idle time, while maximizing throughput and customer satisfaction. In this study, we propose a simulation-based genetic algorithm approach for the joint optimization of RL network design and DLB with sequencing decisions. The use of simulation modeling allows for the consideration of stochastic aspects associated with RL and DLB such as transportation and disassembly times. A numerical example was provided to present the applicability of the proposed approach. Moreover, a sensitivity analysis was carried out to study the impact of various parameters. The results indicate the superior performance of the proposed approach with respect to total cost.

Effect of the COVID-19 pandemic on crowding aversion in public transport and transport mode choice: The case of Santiago, Chile

Mode choice modeling has shown a significant crowding effect over travel time perception. But the recent COVID-19 pandemic and the related sanitary measures have changed perceptions of overcrowding on the mode choice. This study aims to quantify these changes through a hybrid discrete choice model using data collected through a revealed preferences survey applied in two time periods in Santiago, Chile. Although the overcrowding aversion was included in the choice model as a latent variable, that had a significant effect on the mode choice of people only for the set of responses belonging to the first time period, which implies a reduction of the initial pandemic impact. Results also show that women and people younger than 35 years old have higher levels of crowding aversion. By analyzing the disutility generated by each alternative mode, it is determined that the bicycle is preferred over the car for trips of distances less than 4 km. In the same way, for trips of less than 3 km, the walk has a preference over public transport. Regarding the marginal rates of substitution between travel and walking time in public transport, for trips of 30 min with an overcrowding level of 6 pax/m2, women over 35 years are willing to trade 2 min of travel for 1 min of walking. When comparing the rates obtained in a pre-pandemic study, it is obtained that for trips of less than 9 min, people in the pandemic have more preferences for walking over spending time inside public transport.