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Flexible working hours: an end to the ordeal of rush hour?

Emmanuel Munch (Urban planner)
09 April 2019

In the Paris region, more and more workers have working hours that are no longer explicitly fixed by the employer. Instead, they have what we call flexible working hours. According to theories in transport economics, this greater freedom given to employees should spread out people’s starting hours and therefore contribute to improving travel conditions at rush hour. But is this actually the case? Are more flexible working hours really the right solution to end the problems of rush hour congestion? Do employees with flexible schedules actually avoid the morning rush hour? And more generally, how do they choose to set their own working hours?

A paradox: flexible working hours increase the concentration of commutes at rush hour

Based on the latest French National Survey on Transport and People’s Movements (ENTD, Enquête Nationale Transport et Déplacement), I first tried to compare at what time flexible-hour workers chose to start work compared with fixed-hour workers whose schedule is set by their employer. And what I found was, at first glance, paradoxical.

The Paris region, arrival times at the regular workplace, for one day of the week and for the first trip to the workplace. Grouping per 30 minutes. Created by the authors. Source: ENTD 2008.

Overall, we can see on the graph that the workers who can choose their own hours more often synchronize their arrival times with rush hour than people whose schedule is fixed by their employer. From other more advanced analyses and based on the results observed across the Paris region, we can see that giving people more flexible working hours only increases the concentration of rush hour commutes - thus worsening congestion and related issues.

What are the reasons for this? I wondered why employees with flexible hours ended up having schedules that were just as simultaneous - and sometimes even more so - than those with fixed hours. My goal here was to identify new ways of spreading out arrival times at the workplace and to suggest alternative or complementary policies. In order to identify the reasons why employees with flexible hours choose to go to work during the morning rush hour period, between 2014 and 2017 I interviewed thousands of executives working with flexible hours by means of a questionnaire. They all worked in a large business district in the Paris region that includes the headquarters of major corporations in insurance, banking, telecoms and transportation. This analysis was further complemented by in-depth interviews with 30 of these employees.

1. To meet coordinating constraints (family, professional)…

The first explanation for this paradox is perhaps the most trivial: if employees with flexible hours continue going to work during rush hour, it is because some of them have no other choice. In other words, although flexible hours appear to liberate working schedules, employees are still subject to what we call “coordinating constraints” that force them to come to work during rush hour. By “coordinating constraints,” we mean all activities of daily life that need to be coordinated with other people at a specific time and place. They are constraining insofar as people have very little leeway (often none at all) to change the timeline of the activity’s schedule. Among the coordinating constraints forcing employees to travel at peak times, the most important one for parents of young children is school. Another constraint is the need to be present for the first work meeting of the day with colleagues, given that conventionally in the Paris region these meetings almost always start at 9 or 9:30 a.m.

Furthermore, if the time of the first work meeting or the beginning of the school day are not factors, the analysis of the questionnaire reveals that many workers also seek to coordinate their working hours with those of their partners, which can also encourage them to travel at rush hour. Finally, even though we weren’t able to sufficiently analyze this type of result, clearly time constraints relating to the end of the workday (such as children getting out of school, or the practice of leisure or associative activities in the evening) can also indirectly make workers choose to start their workday at peak times. Therefore, the statistical model is able to isolate the effect of one variable on the probability of arriving during rush hour, but not several variables. It becomes difficult to know whether having to meet multiple coordinating constraints can more strongly induce arrival times during rush hour. This is where the interviews proved to be very useful. We found that workers tend to commute during rush hour as a result of trying to successfully schedule all the dif erent activities of daily life. When people have several activities to coordinate and as many other people to meet, rush hour is often the only time slot for starting work that makes it possible to align all the other commitments in daily life.

Consequently, this would be the main reason why women and people working in private companies are more likely to arrive at the workplace during rush hour. Indeed, the analysis of interviews and studies available in the literature show that these individuals have on average more activities to schedule in a day. These results are therefore true for part of our sample, but some workers don’t have any coordinating constraints that primarily determine the time at which they start working. At what time do workers arrive then if they can more freely organize their schedule?

2. To enjoy the social aspects of work...

Some employees who are not forced to coordinate their schedule with that of anyone else (they represent 30% of our sample) prefer to get to work before rush hour. Indeed, 55% of employees who freely choose their working hours arrive at their office before 8:30 a.m., compared to 35% who arrive between 8:30 and 9:30 a.m. and only 10% after 9:30 a.m. Irrespective of chrono-biological preferences, early morning arrivals were motivated by a quest for a quiet office, especially in open spaces before 8:30, as well as enjoying a more comfortable commute by avoiding rush hour.

However, there were some employees who reported a preference for arriving during rush hour, especially to enjoy social opportunities. In this respect, it appears that in almost all of the companies that were studied, these socializing opportunities all revolved around the coffee machine: respondents reported that “between 8:30 and 9 a.m., everyone goes down to get coffee” and that “there’s no one left in the office.”

The opportunity to enjoy coffee with colleagues would also explain why some chose to synchronize their arrival at work. But are these synchronized moments at the coffee machine around 9:00 a.m. always the result of individual preferences and practices that are actually chosen by employees? Or should we also consider them, in some situations, as a form of submission to social norms relating to work schedules?

3. ...or to conform to social norms

The social norms of work schedules rest upon a set of practical rules of conduct that reflect collective values. For instance, it may be frowned upon for a worker to begin his/her day later than others, even if this is just a perceived late arrival. Therefore, there are practical and tacit rules of corporate life pushing workers to arrive at the same time as everyone else. This is precisely what was reported to me by a interviewee who lives far away from her work place and who, after dropping off her children, can’t be at work before 9:45 a.m. She believes that her absence from the morning coffee ritual is damaging and could potentially be detrimental to the advancement of her career. This chronological constraint described here is a norm that concerns all employees because it is a perfect reflection of the values related to labor, in this case discipline.

Here, although individuals now have flexible working hours, the norm for disciplined employees directs them to always arrive at work at the same time; on one hand this has the effect of ensuring the social cohesion of the working group, but on the other it stigmatizes employees who arrive after 9:30 a.m., as they are perceived as being too lazy or easy-going. A typical example of this sentiment would be when a worker ironically asks his colleague who shows up at 10 a.m. if he took the morning off. Late arrivals are therefore potentially penalised by the hierarchy or colleagues - and this can take the form of simple taunts or even complete exclusion from the social fabric of the workplace.

Conclusion : What measures to spread out starting times ?

Giving workers greater flexibility to set their working hours doesn’t lead to a dispersion in the overall arrival times at the office. In the age of flexibility, we don’t live as may be expected, in a world increasingly out of sync where we would write professional emails at 11 p.m. and all do our shopping online at 3 a.m. The social world remains highly synchronized and in the Parisian context at least, professional activity still begins at the same time each day. Whether we are collectively and explicitly directed by the organization of labor or individually and implicitly guided by the management of our daily schedules, our ability to synchronize and therefore preserve social interactions remains very effective. And this is a good thing - except in terms of rush hour congestion. In light of these results and analyses, we suggest three measures that could spread out starting times while maintaining the synchrony of social life:

  • First, slightly diversifying the schedules of preschools and schools among the various Parisian districts.
  • Second, setting a ground rule that no office meetings in companies shall begin before 10 a.m.
  • Finally, and perhaps most importantly, actively communicating about the social norms relating to work schedules.

This is what the Governor of Tokyo, Uriko Koike, did in 2017 with the launch of a campaign called "Jisa Biz" - jisa meaning "time difference" and biz being an abbreviation of business. In a country where public transport is overcrowded at peak times and where discipline is deeply rooted in the professional culture, Koike has made repeated public statements that arriving at work after the rush hour doesn’t mean that someone is working less or not as well as others. In my view, this is the most promising strategy. Norms endure through silence. They can only survive so long as their arbitrary nature isn’t mentioned too often. It is therefore by pointing out and debating these social norms relating to working hours that we can question their persistence in light of their legitimacy and that we create opportunities to rethink them. "Is it really necessary for all Parisians to be at work before 9:30 a.m.?”

Emmanuel Munch

Urban planner

Dr. Emmanuel Munch is a professor-researcher at the Paris School of Urban Planning and the University of Paris-Est, and is part of the City Mobility Transport Laboratory. With a PhD in Urban Planning and Development from UPE (2017), his work relates to chrono-urbanism, the sociology of time and the socio-economics of transportation. His research focuses on the temporalities of urban mobility, daily activity programs, the synchronization of work schedules, the phenomenon of transportation rush hours and urban demand management policies more generally.

To cite this publication :

Emmanuel Munch (09 April 2019), « Flexible working hours: an end to the ordeal of rush hour? », Préparer la transition mobilitaire. Consulté le 28 November 2022, URL:

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