Abstract
The COVID-19 pandemic had a significant impact on travel mode choices in cities across the world. Driven by perceptions of risk and the fear of infection, the pandemic resulted in an increased preference for private vehicles and active modes and a reduced preference for public transit and ride-sourcing. As travel behavior and modal preferences evolve, a key question is whether the pandemic will result in long-term changes to travel mode choices. This study uses data from a web-based survey to examine the factors influencing mode choices for non-commuting trips in the post-pandemic era. Specifically, it uses stated preference data to develop a random parameter mixed logit model, which is used to compare the elasticity of key variables across different income and age groups. The results of the study highlight the influence of sociodemographic attributes and pre-pandemic travel habits on anticipated post-pandemic mode choices. Additionally, the results suggest that frequent users of private vehicles, public transit, and active modes are likely to continue to use these modes post-pandemic. Furthermore, the results highlight the potential for the perception of shared modes to influence post-pandemic mode choice decisions. The results of the study offer insights into policy measures that could be applied to address the increased use of private vehicles and reduced use of transit during the pandemic, while also emphasizing the need to ensure that certain segments of the population can maintain a sufficient level of mobility and access to transport.
The COVID-19 pandemic had a significant impact on activity and travel behavior, including participation in out-of-home activities and travel mode choice. As the world continues to recover from the effects of the pandemic and daily life progresses toward pre-pandemic normality, it remains to be seen whether the pandemic will have a long-term impact on travel behavior. Any such impact would have important implications for transportation planning in the post-pandemic era, particularly if the pandemic has changed travel habits and modality styles, which are aspects of an individual’s lifestyle that refer to the travel modes they habitually use (
Travel mode choices have important implications for the transportation system and its users. Choices made by travelers play an important role in the short-term (e.g., service planning, road space allocation) and long-term (e.g., infrastructure investments, transportation master plans) management of the system. Additionally, the options (or lack thereof) available to individuals have an impact on their mobility and accessibility (
This study examines the factors influencing anticipated post-pandemic mode choices for non-commuting trips among residents of the Greater Toronto Area (GTA). The focus on non-commuting trips is motivated by the positive impact of maintenance and discretionary activities on both physical and emotional well-being (
The remainder of the paper is organized as follows. First, a review of previous studies focusing on the impacts of COVID-19 on pandemic-era and anticipated post-pandemic travel mode choices are presented. Next, the design and administration of the survey are described, descriptive statistics of the survey sample are presented, and the process used to design the SP experiments is outlined. Then, the formulation and final specification of the empirical model are presented, and the results of the elasticity analysis are summarized. Finally, the implications of the results of the study are discussed.
Literature Review
The disruptions caused by the COVID-19 pandemic have resulted in considerable effort being dedicated to studying its impact on travel behavior. Aside from participation in activities outside of the home, these studies often focus on the impact of the pandemic on modal preferences, utilizing either passive data or survey data. The studies have consistently found that the pandemic resulted in a reduced inclination to use shared modes, including public transit and ride-sourcing, and an increased inclination to use private vehicles and active modes (
The modal shifts that have resulted from the pandemic have been attributed to attitudes toward the pandemic and perceptions of risk. Specifically, studies on the topic have typically found that attitudes toward public transit and ride-sourcing have become more negative. In contrast, attitudes toward private vehicles and active modes have either been unaffected or have become more favorable (
In addition to descriptive analysis, mode choice decisions during the pandemic have also been examined through the use of econometric models. Aside from the typical determinants of mode choices (e.g., travel time and travel cost), studies on the topic often find that mode choices during the pandemic were influenced by pre-pandemic travel behavior. For example, Costa et al. (
Aside from travel behavior during the pandemic, a limited number of studies have investigated the potential nature of post-pandemic modal preferences. Although these studies offer insights into post-pandemic travel behavior, they tend to focus on whether a specific mode will be used. For example, using protection motivation theory, Mashrur et al. (
Despite these efforts, additional work is required to understand the determinants of post-pandemic mode choices better. To date, studies on the topic have focused more on understanding whether a mode will be used, rather than examining the factors influencing the decision to use a certain mode for a given trip, as outlined in Table 1. To the authors’ knowledge, there has as yet been no study that examines the determinants of travel mode choices through the lens of random utility theory. Consequently, relatively little is known about the extent to which personal attributes, trip-related attributes, and perceptions of risk influence the decision to use a given mode for a specific trip. This is a significant research gap, because understanding the determinants of post-pandemic mode choices will be essential for transportation planning and policy decisions. This study aims to contribute to the literature by analyzing the determinants of post-pandemic mode choices through the estimation of an econometric model. Specifically, it uses SP data collected through a web-based survey to estimate a random parameter mixed logit model of travel mode choices for non-commuting trips. In addition to offering insights into post-pandemic model preferences, the results of the study can also shed light on the extent to which mode choices are affected by perceptions of risk and pre-pandemic travel behavior.
Outcomes of Interest of Post-Pandemic Mode Choice Studies
Data and Methods
Survey Design and Administration
The data used in this study were collected as part of the Study into the Use of Shared Travel Modes (SiSTM), whose primary goal was to understand the impact of the COVID-19 pandemic on ride-sourcing in the GTA. As part of the SiSTM, two cycles of a web-based survey were conducted, one in July 2020 and another in July 2021. In the SiSTM surveys, respondents were asked (among other things) to answer a series of questions with regard to their sociodemographic attributes, travel behavior before and during the pandemic, and their attitudes toward the pandemic. Additionally, they were asked to complete a series of SP experiments pertaining to mode choice for commuting and non-commuting trips during and after the pandemic. In the survey, the post-pandemic period was defined as the period during which COVID-19 is no longer a public health threat.
This study uses data collected through the second cycle of the SiSTM survey. As shown in Figure 1, the second cycle was conducted during a period in which the number of new COVID-19 cases being reported was relatively low. As a result, the public health measures that were in place during the survey period were relatively relaxed compared with periods that had higher case counts. The second cycle was also conducted at a time during which the number of Ontario residents receiving their second dose of the COVID-19 vaccines available in the province was on the rise and test positivity rates were relatively low (as shown in Figure 2).

COVID-19 case counts and cumulative deaths in the GTA.

Vaccine doses administered in Ontario and COVID-19 test positivity rates in the GTA.
The SiSTM survey was coded into a web-based survey interface, and a link to access the survey was sent to a market research company. The company then invited a random sample of the members of its consumer panel to participate in the survey, providing non-monetary compensation upon completion of the survey. As part of the administration of the survey, a residential location quota was imposed to help ensure that the distribution of the home locations of the survey respondents was consistent with that of the study area. The minimum required sample size for the survey was informed by the standard error of the experimental design, the sample size standards for SP studies outlined in Rose and Bliemer (
Descriptive Statistics
The distributions of key personal and household attributes are summarized and compared with the 2016 Canadian census in Table 2. Compared with the study area, women are slightly overrepresented in the sample, as are the residents of Toronto, Peel Region, and York Region. Given that public transit usage is much more prevalent in Toronto compared with the rest of the study area (
Comparison of Key Sociodemographic Attributes—SiSTM Survey versus Census
As part of the SiSTM survey, respondents were asked to indicate the frequency with which they used various modes of travel before the pandemic for commuting and non-commuting trips. As shown in Figure 3, driving was the mode used most frequently for non-commuting trips, followed by public transit and walking. Conversely, taxi, ride-sourcing, and bicycle were the modes that were least likely to be used by the respondents for non-commuting trips. This is relatively consistent with the choices made in the SP experiments, as shown in Figure 4. Interestingly, the percentage of respondents choosing to use public transit and to be driven by someone they know is roughly equal. In addition, the percentage of people choosing transit in the SP experiments is lower than that of the percentage of respondents indicating that they used transit in the pre-pandemic period.

Summary of modes used for non-commuting trips before the pandemic.

Distribution of responses to post-pandemic SP questions for non-commuting trips.
At the time that the second cycle of the SiSTM survey was conducted, the Alpha, Beta, Gamma, and Delta variants of the SARS-CoV-2 virus had been identified (

Concerns about different aspects of the pandemic among respondents.

Level of agreement with statements regarding changes in concern and perceptions of risk.
Experimental Design
The SP experiments were designed to gain insights into the determinants of post-pandemic mode choice decisions. The alternatives and their corresponding attribute values are summarized in Table 3. The alternatives included in the SP experiments were chosen based on the travel modes available in the study area. In contrast, the attributes were chosen according to a review of similar studies. The
Attributes of the Alternatives Included in the SP Experiments
Based on these reference values, the baseline values of the travel time and cost attributes were calculated. The baseline values were then modified to create a set of levels for each attribute. The travel time for motorized modes was calculated based on an assumed speed of 45 km/h, whereas that for public transit was based on an assumed speed of 40 km/h; both speed values were based on the experimental design outlined in Weiss et al. (
Similarly, the cost associated with each mode was determined according to an assumed per-kilometer and/or per-minute cost. The cost of the
In addition to the attributes in Table 3, the experimental design also included two contextual variables: the number of doses of a COVID-19 vaccine received by the respondent; and whether mass vaccination had been achieved. The D-efficient approach was used to design the SP experiments, and Ngene software was used to produce the combinations of attributes that would be shown to respondents (i.e., choice situations). D-efficient design aims to produce experimental designs that, when used to estimate a statistical model, yield parameters with standard errors that are as low as possible (
Empirical Model and Results
Model Formulation
The respondents’ post-pandemic mode choices were modeled using a mixed logit model. Compared with the MNL model, mixed logit models can accommodate preference heterogeneity, correlations among unobserved factors, and unrestricted substitution patterns between alternatives (
where
The random parameter mixed logit model developed in this study uses the same choice probability as the MNL model. However, because the model includes random parameters, the probability of person
where
As part of the SiSTM survey, each respondent was asked to complete three choice experiments. Consequently, let
where
The likelihood function of the model is given by:
where
The random parameter mixed logit model was estimated using the Apollo package written for the statistical computing software R (
Final Specifications
The final specification of the random parameter mixed logit model is summarized in Table 4 under the heading “Final model.” During the model estimation process, variables corresponding to sociodemographic attributes, attitudinal information, and SP attributes were tested. Additionally, the frequency with which an individual used various modes of travel before the pandemic was included in the model. Specifically, the response options outlined in Figure 1 were coded numerically from 0 (never) to 4 (daily). Taking such an approach to include this information in the model implies that the effects of these variables are linear. The decision to retain a variable in the model was made based on the sign and robust
Final Model Specifications
Notably, the inclusion of the SP attributes corresponding to health and safety was not supported by the sign and
The random parameters included in the model were specified as log-normal variables, because they were used to capture the influence of travel time and cost on travel mode choices. As Train (
Aside from the attributes of the alternatives, sociodemographic attributes were also found to influence post-pandemic mode choices. In particular, the age of the respondents was found to influence the decision to drive oneself or use hailed modes of travel (i.e., taxis and ride-sourcing). This is consistent with previous studies, which have found that older individuals tend to favor travel in private vehicles. However, these results also contradict the work of Ozonder and Miller (
Despite the absence of pandemic-related SP attributes in the final model, the results suggest that perceptions of risk also have the potential to affect post-pandemic mode choices. Specifically, those who indicated they would be less willing to use shared modes compared with before the pandemic were less likely to choose public transit. This reluctance, which was also reported in Currie et al. (
Furthermore, pre-pandemic travel behavior was found to affect post-pandemic mode choices. Specifically, using a given mode frequently before the pandemic increased the likelihood that the mode was chosen in the SP experiments. This finding suggests that the extent to which a person used a given mode before the pandemic offers insights into whether they will continue to use the mode in the post-pandemic period. Previous studies have found that even when faced with changes in the decision context, habits formed before the change can still influence behavior following it (
Based on the final specification of the
Elasticity Analysis
Although the model results help provide insights into the determinants of post-pandemic mode choices, they primarily indicate whether a variable increases or decreases the probability of an alternative being chosen. Direct and cross elasticities were calculated to help understand and quantify the extent to which changes in key variables affect mode choices. The elasticities corresponding to two variables were calculated: parking cost of the
Sample-Level Analysis
The direct and cross elasticities for the sample were aggregated using sample enumeration and are summarized in Table 5. The results suggest that increasing parking costs would have the greatest impact on the use of ride-sourcing, taxis, and public transit. The shift from private vehicles to taxis and ride-sourcing vehicles would have a detrimental impact on sustainability, because these vehicles spend time deadheading while in operation (
Direct and Cross Elasticity with Respect to Key Variables (Sample Averages)
Denotes direct elasticity values.
Comparison across Income Groups
To compare the direct and cross elasticities of the variables of interest, three income categories were defined: households earning less than $50,000 annually (group I1); households earning between $50,000 and $100,000 annually (group I2); and households earning over $100,000 annually (group I3). In the interests of brevity, only the elasticities of public transit and private vehicles/ride-sourcing are discussed. Kernel density plots are used to compare the distribution of elasticities across the groups. As shown in Figure 7, the lowest income group shows a greater sensitivity to an increase in parking costs than the other income groups. Additionally, individuals from income group I3 are slightly more likely to shift to public transit in response to an increase in the cost of parking. Such a shift could have a detrimental impact on lower-income households, because previous research has shown that the competitive housing market in the study area has resulted in these households moving to areas with lower levels of transit accessibility (

Elasticity of the

Elasticity of the
Interestingly, the cross elasticity for exclusive ride-sourcing in relation to transit out-of-vehicle travel time is greater for group I1 than for groups I2 and I3. This could be a reflection of the growth in the generation of ride-sourcing trips in lower-income areas that was observed pre-pandemic, or it could be the result of the complementary role that ride-sourcing can play in areas with lower transit accessibility (
Comparison across Age Groups
Similar to the analysis of elasticities across different income groups, three age categories were defined: those aged 30 and younger (group A1); those between the ages of 31 and 64 (group A2); and those aged 65 and older (group A3). As shown in Figure 9, the sensitivity to parking costs when a person is driving appears to be lower for older age groups. This may stem from the tendency of transit and active mode usage to be more prevalent among younger individuals and the tendency for older individuals to favor travel by private vehicle (

Elasticity of the

Elasticity of the
Discussion
The results shed light on the factors influencing mode choice decisions in the post-pandemic period, defined in this study as the period of time during which COVID-19 is no longer a public health threat. In particular, the results shed light on the influence (or lack thereof) of pandemic-related factors on anticipated post-pandemic mode choices for non-commuting trips. Similar to studies on mode choices during the pandemic, the findings suggest that perceptions of risk have the potential to influence the decision to used shared modes post-pandemic. Moreover, the frequency with which a mode was used pre-pandemic was also found to influence post-pandemic mode choices. However, the variables corresponding to health and safety measures were not found to have a statistically significant influence on post-pandemic mode choices. Overall, these results suggest that post-pandemic mode choices could resemble pre-pandemic mode choices, with discrepancies between the two being driven by lingering perceptions of risk and a reluctance to use shared modes.
In addition, the results offer insights into the extent to which pre-pandemic determinants of mode choices influence post-pandemic mode choice decisions. Overall, it appears that sociodemographic and level-of-service attributes influence post-pandemic mode choice decisions to a greater extent than perceptions of risk and other pandemic-related factors. However, the latter two still have the potential to influence the decision to use shared modes in the post-pandemic period. This information can help inform efforts to examine whether the changes in travel mode choices resulting from the pandemic, namely, an increase in private vehicle usage and a reduction in transit ridership, will persist post-pandemic. Moreover, these findings can help inform the development of policies that aim to address this trend and help encourage the use of more sustainable modes of travel.
Based on the outcomes of pre-pandemic studies and the results of this study, an increase in parking costs could help mitigate the increase in private vehicle use that occurred as a result of the pandemic. However, the implementation of such an increase must account for the modes that are available to trip-makers. In the absence of viable alternative modes of travel, individuals may opt to bear the increased costs or change their destination. Moreover, a reduction in driving in response to an increase in parking costs has the potential to increase ride-sourcing usage, which would not result in a reduction in vehicle kilometers traveled. This was exemplified in the results of this study, because the possession of a driver’s license increased the likelihood of an individual choosing exclusive ride-sourcing and the reluctance to use shared modes reduced the likelihood of an individual choosing transit. Such a shift could be mitigated through the introduction of a surcharge for trips made to areas with high transit accessibility, although this policy could have a disproportionate impact on lower-income individuals. Furthermore, the results of the elasticity analysis show that an increase in parking costs would have the greatest impact on individuals from lower-income households, which could have an adverse impact on their mobility and accessibility. Ensuring that other modes, particularly public transit, provide a reasonable level of mobility and accessibility is also an important consideration with regard to helping older members of the population retain sufficient levels of mobility and avoid transportation disadvantage (
Additionally, the findings of this study suggest that transit usage could be less prevalent in the post-pandemic period than it was in the pre-pandemic period. This decline in transit usage could pose several challenges, particularly if trips that were previously made using transit are made by private vehicles, ride-sourcing, and taxis in the post-pandemic period. Although the implementation of mask mandates and the disinfection of vehicles were not found to influence the decision to use transit, the results suggest that reducing overcrowding could help mitigate a decline in transit use by assuaging concerns about the use of shared modes. This could be achieved by increasing the frequency of transit services, although this would likely require additional funding given the decline in fare revenues caused by the pandemic. Similarly, transit agencies could make use of data obtained through automated fare collection and automated passenger counting systems to make real-time information on crowding levels on individual transit vehicles publicly available. Both measures can help rebuild public confidence in public transit, which is a key factor in helping transit ridership recover to pre-pandemic levels (
Previous studies have found evidence that newer generations of seniors (i.e., those over 65) are more likely to rely on private vehicles for mobility than their predecessors (
Conclusions and Future Work
This study presented the results of an investigation into the determinants of anticipated post-pandemic mode choices for non-commuting trips among residents of the GTA. Using data from a web-based survey, the study developed a random parameter mixed logit model based on information collected through a series of SP experiments. The model was used to compute the direct and cross elasticity of key variables, which were then compared across income and age groups. The model results highlight the influence of sociodemographic and level-of-service attributes on post-pandemic mode choices. The results also suggest that pre-pandemic travel habits offer insights into post-pandemic modal preferences. Specifically, the frequent pre-pandemic use of a mode increased the likelihood that it was chosen in the SP experiments. In addition, the results suggest that certain individuals may still be reluctant to use shared modes in the post-pandemic period. Furthermore, the results of the elasticity analysis show that the effects of potential transportation demand management strategies would differ across income and age groups. Although the study offers insights into approaches that policymakers could take to combat the increase in private vehicle use and reduction in transit use that have resulted from the pandemic, it also highlights the need to ensure that a sufficient level of mobility and accessibility can be maintained without the use of a private vehicle.
The key limitation is that the results are based on an analysis of SP data pertaining to post-pandemic mode choices. In addition to the long-standing issues associated with the hypothetical nature of SP data (
Future studies could build on the work presented in this study by incorporating latent attitudinal variables into their analysis through the use of factor analysis, structural equation models, or the integrated choice and latent variable model. Doing so would allow the researcher to examine the impact of latent attitudinal factors and perceptions of risk on post-pandemic mode choices. Future studies could also estimate a similar model using the error component mixed logit formulation, which would allow more complex substitution patterns to be captured in the model. In addition, future studies could utilize SP experiments whose attribute values are pivoted off the attributes of trips reported by the respondents. Taking a pivoted approach to designing the experiments has been shown to assist in improving the behavioral realism of the responses, which can help address the issues stemming from the hypothetical nature of the data (
Footnotes
Acknowledgements
The authors would like to thank the three anonymous reviewers whose constructive feedback helped improve the quality of the paper.
Author Contributions
The authors confirm contribution to the paper as follows: study conception and design: P. Loa, K. Habib; data collection: P. Loa; analysis and interpretation of results: P. Loa; draft manuscript preparation: P. Loa, K. Habib. All authors reviewed the results and approved the final version of the manuscript.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
