Experimental Design Details
Participants are excluded if they are retired or unemployed. Students are included. We further exclude those who cycle or walk to work and those who work entirely from home. Participants are randomly assigned to two groups, excluding anyone with potential morning commute time savings of less than five minutes. Time savings are determined by comparing participants' regular commute durations with their estimated commute times without delays.
Before randomly assigning participants, we assess whether participants' jobs or activities (such as shift work or school) require a fixed start time. This way, we measure the willingness to arrive earlier or later than the desired time for both participants who have flexible schedules (e.g., those with flexitime) and those with fixed schedules (e.g., shift workers, students). So, participants flexible and not flexible are randomly allocated to these two groups. For those who are not flexible, it is a hypothetical setting. Understanding schedule flexibility in this hypothetical context is valuable, as it allows us to assess potential flexibility limited by “external” factors rather than commuters’ habits. These “external” factors could be changed by political action. For instance, schools could consider introducing more flexible schedules, or firms might modify their shift schedules.
Group 1: Participants in this group are asked two questions in an open-ended question format about how much time they would need to save to leave 30 minutes earlier or later for work. They are then asked, in two separate open-ended questions, how much money one would need to give them to leave 30 minutes earlier or later.
Group 2: In the vein of a multiple price list going in certain minute steps participants are asked for each item whether they would leave 30 minutes earlier if they could save the respective amount of time by doing so. This list is limited to the “real” options participants face based on data how long it usually takes them to go to work and how long it would take them in an ideal setting without traffic/delays. In a second step, they receive another list where they can indicate whether they would accept a specific monetary value offered for leaving 30 minutes earlier or not.
Those excluded due to the time saving criterion are individuals who cannot significantly reduce their commute time (less than 5 minutes). All of these participants are given open-ended questions as the first group, to assess their willingness to arrive earlier (not later). This is then a hypothetical setting for the participants.
In addition, we examine commuting preferences, particularly in terms of preferred morning departure times. We also assess factors that influence when participants leave for work (or school), considering reasons such as current traffic conditions, pre-work appointments, dropping off children at school or daycare, and the potential to work from home. We also ask for reasons for not adjusting their departure times despite potential time savings (if there is a potential). These questions are designed to provide a comprehensive understanding of participants' morning commute preferences and the reasons behind them. This helps us to explore the potential for travelers’ schedule flexibility.