For a researcher, the concept of mobility, as it is used in everyday language and in the field of transport, suffers from three fundamental shortcomings:
<br><br />
### Shortcomings linked to everyday language
<br>
#### 1. A strictly spatial concept

The first shortcoming is that the concept is strictly spatial in its ordinary meaning. In other words, it refers to how we move and travel in space but does not take into account the social aspect of mobility—the fact that, when we move, we do so not simply for the sake of moving, but to partake in potentially different kinds of activities and, hence, take on different roles. Thus, there is an inherently social dimension to mobility.
<br><br />
#### 2. Tangible movement

The second shortcoming is that mobility, in common usage, refers to something that can be measured, meaning a journey from point A to point B and thus what is done in practice. However, this does not really account for potential mobility—the fact that there are journeys we make, but also journeys that we could undertake and choose not to.
<br><br />
#### 3. An objectified data

The third shortcoming is that mobility, as it is typically measured and understood, is something entirely objective or objectivised, meaning we can measure it statistically in terms of traffic volume, origin, destination, speed, number of kilometres, mode of transport, motives, etc. However, by thinking this way, we overlook a whole other aspect of the concept: the fact that mobility is also a value. Every trip has not the same value. Travelling by car or on foot does not give us the same self-image. Nor are origins and destinations neutral, as international migrants will tell you. Each of these issues must be made central to the notion of mobility in order to really work with the concept.
<br><br />
### Tackling the "mobility turn"

These three shortcomings are widely recognised in the field of research. Since the turn of the millennium, they have given rise to a whole body of research, notably in English-speaking world, under the title "research on the mobility turn". The work we do at the EPFL and at the LaSUR is part of this movement. At the same time, we attempt to avoid three pitfalls which, at times, seem to reflect the failings of research on the mobility turn, ultimately leading to other limitations. It would be a shame to replace one unsatisfactory concept of mobility with another one with its own problems.
<br><br />
### Recent pitfalls in interpreting the concept of mobility
<br>
#### 1. Refocusing the concept of mobility

The initial problem I see in some of these works is the tendency to make mobility such a broad concept that we no longer know exactly what we are talking about. In other words, if mobility becomes a vast topic that includes ideas, objects, information and people, it becomes so vast that, in the end, it merges with communication and movement in the broader sense, which is unfortunate. Such a definition of mobility prevents us from conducting targeted research and conceptualising specific issues.
<br><br />
#### 2. More mobility but continued inequality

Another pitfall in some of the works on mobility is to see mobility as a concept that is consistent with the liquefaction of space and society, meaning that people move more, objects move more, information circulates more and, as a result, make disappear what sociologists have long called "social structures". I believe there are risks to such an approach: the fact that we move a great deal does not necessarily mean there are fewer inequalities between different socio-professional groups, men and women, generations, etc. On this point, again, I think it is important that we be wary of basing our definition of mobility on the image of a world in which people enjoy more freedom because they move more, and where differences and inequalities tend to be blurred because we are more mobile and freer. We are not freer, even if we do move more, and social structures are undoubtedly just as strong as they have ever been.
<br><br />
#### 3. Going faster and further does not make us more mobile

The third stumbling block is the tendency to measure mobility based on how fast we move and how far we go, with the more or less implicit idea that people who move fast and travel great distances are somehow more mobile than those who move slowly and locally. This is essential, especially when studying what many call "highly mobile people", namely those who commute long-distance on a daily basis, who might have several hundred kilometres between their home and their place of work, and who may even have a small pied-à-terre in the city where they work. They are dubbed "highly mobile" because they travel further and faster than most people do on a daily basis. The problem I have with the term "highly mobile" is that I believe we must take great care not to define mobility as based on speed or distance travelled. If we use a more comprehensive definition of mobility, then there is nothing to suggest that it is because people travel a lot or quickly that they are more mobile than people who might travel more frequently but in a smaller perimeter. I have talked a lot about shortcomings in the concept of mobility as it is used in common parlance. There are, for instance, many transport departments in towns and cities that have changed their name to "mobility services" or "mobility departments". This takes us back to those initial shortcomings. Such bodies handle transport services, and nothing more. They changed their names because "mobility" was a buzzword, but basically nothing has changed.
<br><br />
### Redefining the concept of mobility

To adopt a position in this field and overcome these shortcomings, we at the EPFL—in partnership with other research networks—have developed an original approach to mobility that divides the concept into two aspects: "mobility" and "motility". Mobility here is considered as the intention and act of moving in space, which implies social change. This twofold definition overcomes the initial shortcomings by incorporating aim and action, potential and fulfilment, and social and spatial aspects. Based on this definition, we can incorporate factors including experiences and values associated with mobility. This is quite a broad definition, yet it does not take into account the entire scope of communication. This definition does not cover "virtual" mobility, meaning remote communication. Here we are talking about actual physical movement through space by actors, be they individuals or groups. In this case, we are talking about individuals. With this in mind, let us explore the concept of motility.
<br><br />
### Motility: the ability to move

What is motility? No, it’s not a typo. "Motility" is a term borrowed from biology that means "capable of moving". The word is often used by biologists and is borrowed by social scientists. Motility is the set of factors that allow us to be mobile. When we want to move, we call upon a variety of specific characteristics. What are these characteristics?
<br><br />
#### 1. Social conditions of access

We all have varying degrees of access to transport and communication networks, but that is just one factor.
<br><br />
#### 2. Skills

Motility also involves skills, it is the way we organise ourselves. Some people are always late, and others are never late: it's simply a matter of organisation. Some people can easily look ahead and think to themselves, "I'm looking forward to all of the things I'm going to do tomorrow". Others will think, "I'll have to cut something out because otherwise it’s going to be a pain"; others will find it harder to think this way. So there is a whole set of factors like that, which are related to individual skills. Some aspects are more matter-of-fact. For instance, if you are a regular Paris Metro user, you know exactly which station to change at to avoid walking through endless tunnels to get to your destination more quickly. That is also a skill, like knowing which roads to take to avoid traffic. Thus, motility refers to issues of access, conditions of access and skills.
<br><br />
#### 3. Plans

Third, motility also relates to what we want to do. We may or may not like travelling, for various reasons: we may enjoy it or try to avoid it whenever possible. In some respect, this is another way of using the options open to us. We are not always on the go or do not make daily long journeys simply because we have access to a car. We do not necessarily use a tram just because it’s close to where we live. This is where the question of desire comes into play. The issue of plans and desires with regard to mobility is all the more important given that we are in a world of hyper-choice. There are so many options open to us and, as a result, we often find ourselves facing choices of modes of transport, how to organise our lives, whether or not to travel, and so on. This third aspect involving mobility plans and how we use the options open to us is of key importance. So, motility includes access, skills and plans. All of these things contribute to the way we move. It is through this filter that we move, with all of the constraints inherent to our daily lives. Here we are talking about people’s motility in daily life, but it is a concept that also applies to companies, i.e. collective actors.
<br><br />
### Considering mobility prior to travelling

Through this approach, we are able to overcome the initial shortcomings to consider mobility as seen by the individual. Motility comes into play before the journey even starts, through our personal access, skills and plans. So the actual journey is but the result of motility. Therefore, we have chosen to develop this approach, as it allows us to tackle heuristically a number of specific issues accurately. For instance, this kind of approach allows us to distinguish between intention and action in terms of mobility. Here’s an example. One of the most striking things about conducting a survey on residential choices is that there are many people who, for instance, choose to live in the city centre, even if it means paying a high rent for a small flat. They will often say, "For me, the most important thing is having everything at my doorstep…there are cinemas, four bookshops, theatre, all kinds of places to do shopping, etc. in a two-kilometre radius". After listening politely, the person conducting the survey will then ask: "But do you actually do all of these things?" And very often, the answer is "no". Potential remains in its potential state. "If I want, I have access to all of these services and facilities. The important thing is knowing they’re there, not necessarily using them". In this case, mobility remains in its potential state. Using this model we can draw a clear line between intention and action.
<br><br />
### Mobility involves social change

We can also easily distinguish between the spatial and social aspects of mobility. This is another key point. We live in a world where there is no longer any clear link between the distance we travel on a daily basis and our social mobility. This is very abstract, so let me give you an example: a person who lives in an urban neighbourhood, spends five minutes getting to work on foot, comes home at noon for lunch and then goes back to work in the afternoon has very local mobility but is actually quite mobile. Each journey involves a change of role: he leaves home to go to work, which involves a change of role; he leaves home, where he may be a father, lover or husband; he arrives at work, where he might be the boss or an employee; and when he returns home for lunch, he changes roles again. So, to a certain degree, there is a clear connection between movement and social realm. With each move, he is socially mobile. Take another example: a sales representative with a major international firm criss-crosses the globe and spends a lot of time in international hotels and aeroplanes. He speaks English and at least one more language, travels countless miles for his job, but always plays the same role in the same sorts of environments. Although he travels great distances quickly, socially speaking he is not very mobile because he is always in the same position. Motility, in conjunction with mobility, when applied to the analysis of individual behaviour, has the advantage of allowing us to establish a relationship between the aforementioned factors. Without this concept - this dual approach - it is much more difficult to study the different aspects. To me, this is essential because we live in a world where, on the one hand, the intention dimension, the potential at our disposal, is extremely important. It is also central to the issue of social inequalities, which brings us back to the concept of motility as regards to the movement of individuals. This is a point that I believe is very important conceptually for understanding movement and mobility. The other key factor here is that we live in a world where mobility and movement are not necessarily linked, like in the second example I gave you. Travelling fast and far does not necessarily make us more mobile socially, require more changes of role or involve a wider range of functions in space and time. This last point is absolutely crucial because mobility in the sense of change or the possibility of change is undoubtedly a core value in Western society. However, it is sometimes confused with movement in space. If we acknowledge that "people who travel further and faster are not necessarily more mobile than others, and are sometimes less so", then we can clearly revisit the issue in a new light