Highlights

Exploring data from Spain’s National Household survey from 2018 to 2022 evidenced the following:

-- Our transportation expenses are increasing. They haven't reached pre-COVID-19 numbers, but the rise has been steady since 2020.

-- The EDA suggests that using shared mobility is contributing to this increase.

-- The use of shared mobility is increasing among families with and without car availability.

-- Families that own a car seem to spend more on shared mobility services.

Introduction

Have you taken an Uber, an electric scooter, or a bike? BlaBlaCared somewhere? If the answer is yes, you already know shared mobility services —perhaps more than you might think.

Another question: Are these services helping you save money or increasing your transportation expenses? In my case, they have contributed to a rise in my mobility expenses over the last few years. If you are also unsure about how you are doing, you are in the right place.

I usually use public transport like the metro, bus, and tram. I started using shared mobility apps with BlaBlaCar for long trips to split costs and Uber for city center travel. I preferred Uber over traditional taxis because it provided fare estimates before the trip, helping me choose between transportation modes.

Now, let's define shared mobility properly because the term includes many other transport modes. I asked ChatGPT for a shared mobility definition, and its answer was: “Shared mobility services are transportation services and resources that multiple people use simultaneously or one after another. These services aim to make transportation more efficient by reducing the need for individuals to own their vehicles and using existing transportation options better” (OpenAI, 2024). Scientific research defines it as an alternative means of travel that aims to optimize the use of mobility resources, potentially reducing many burdens of transportation like traffic jams, parking, pollution, etc. (Machado et. Al, 2018). In simple terms, it is all about using the vehicles we have now more efficiently.

Another important example of shared mobility is vehicle sharing, including car, bike, and scooter sharing. This involves multiple users sharing a vehicle. These vehicles can be either docked at fixed stations or dockless and can be found throughout the city. For example, the bikes in the previous figure are docked, while those in the next one are dockless and can be left almost anywhere within app-specified limits.

During COVID-19, I used shared scooters to avoid public transport crowds, and several friends also used car-sharing. There is a type of carsharing that I haven't tried, which is peer-to-peer carsharing. This is when you use a car owned by another individual (instead of a company). This is a good way of earning extra cash from your car instead of having it parked (as they say, cars spend almost 95% of their time parked).

Blablacar and Uber fall under carpooling and ridehailing. Carpooling involves sharing a ride to a common destination, often arranged through apps where you can share rides with strangers. It started as informal arrangements between people who shared trips aiming to save and keep company. For example, coworkers who alternate driving to save on fuel costs. Ridehailing services like Uber and Lyft must be booked in advance; you cannot stop them on the streets, like taxis.

Now that we know what shared mobility is let's move on to the question that interests us most. As we have seen, sharing a vehicle, in principle, reduces the number of vehicles on the streets while helping you save money. But is this true? Are we spending more on all these new ways of moving?

To answer these questions, I used data from Spain's household budget survey in Spain, the country I live in.

The data

As mentioned above, the datasets I used to explore these questions come from the household budget survey. But what exactly is this? The household budget survey is a detailed investigation of expenditures carried out by major statistical offices, in our case, Spain’s National Statistics Institute. It describes how much families spend on everything: food, clothes, transportation, vacations, housing, etc. It also includes information regarding family members, where they live, net income, etc. This information is used to infer living conditions, consumption patterns, etc. It is so detailed that you can see the average expenditure of a Spanish family on bread or candles. This level of detail allows us to explore transportation and answer our questions of interest.

I used data from 2018 to 2022 to see changes over the years. The information is available to download in this link.

How much are our shared mobility expenses?

Wait! what are our transportation expenses like?

Let's first see how much we spend on transportation overall, shall we? On a daily basis, we commute, move for leisure, and run errands, so, excluding vacations, this spending should not be much, should it? Surprisingly, or not, transportation is commonly the second highest expenditure after housing. The following graph shows the total spending by all Spanish families on transportation from 2018 to 2022. The total surpassed 800 thousand euros in 2019—that’s a lot of money.

What exactly is included here? Well, we have all vehicle purchases, metro tickets, fuel, parking, tram tickets, buses, etc. spent in Spain, considering its whole population. This is collective and individual metropolitan mobility. Long-distance mobility expenses (regional, intercity, high-speed rail services, long-distance buses, and ferry tickets) are not included because they would add some complexity to the analysis.

Now, let's check some numbers that we can compare to ourselves by examining how transportation expenses look for each family on a monthly basis. The following plot shows the median monthly spending on metropolitan transportation per family.

Well, around 200€ per family. Reasonable, no? In my case, I spend around 55€ each month, considering my family of 2, this would add up to 80€.

The 200€ median includes spending on fuel, train tickets, and shared mobility all combined, so it would be difficult to see if those 200€ are mostly made up of one or another. Let's see how much of that monthly expense is due to private mobility (having your own car), public transportation, and shared mobility.

First, let’s explore how much people with cars spend. Usually, the monthly expenses related to owning or using a car are gas refueling, parking, and maintenance (this analysis does not include spare parts, tires, accessories, etc., because these can vary too much depending on the type of car and the type of user). Considering only these three categories (fuel, park, and maintenance), the median spent using private cars would be like this:

This shows that the median is below 100€. The mean is slightly higher, almost reaching 160 €, as shown in the next figure. Both quantities seem reasonable if we consider we are talking about families, not individuals; some people have long commutes to work, drop children at school etc.

As mentioned before, the dataset used in this analysis also includes information on the families’ composition. This information is useful for exploring which family aspects relate to how they spend on transportation. For instance, larger families usually move by private transportation (car, SUV, etc.), or families living in smaller cities with fewer public transportation options also use their own cars. I live in a big city with great public transportation options, and I move by myself, so I mostly use public transportation. Since these characteristics highly impact how we decide to move and we have this kind of data in the Survey (family members, municipality size, ages, genders, etc.), I thought it would be useful to see how they relate to private mobility.

A simple way of exploring how variables are related in data analysis is through correlation matrixes. A correlation matrix is a statistical representation used to examine the relationship between variables in a dataset. Fig. 8 shows a matrix that combines vehicle ownership with family characteristics like salary, number of members, age, gender, education level, etc.

Values in the matrix go from -1 to 1, with higher values showing a stronger relationship between variables. In our case, the variables showing the most correlation to owning or not a car are the neat income and the families’ size (as expected), followed by the breadwinner's education.

Fig. 9 shows another correlation matrix. Here, instead of vehicle ownership, the fuel expenditure is explored. The idea behind this matrix is to see the characteristics of the family that relate to a higher fuel expenditure. In this case, the variables with higher impact are the breadwinner’s age, family size, and the municipality’s size. The impact of these variables is not as strong, but it makes sense that people in smaller municipalities rely more on private vehicles.

Let's move on to explore public transportation expenses. The following graph shows the expenditures on metro tickets, local trains, buses, trams, and combined transportation tickets.

As shown in Fig. 10, the mean expenditure on public transportation was lower than 40€ for the period considered; this seems reasonable. Interestingly, the mean seems to have increased after 2020, when many European cities started providing free and reduced transportation tickets.

Fig. 10 shows the mean and not the median because the median returned extremely lower values, which suggests that many families do not have public transportation expenses. To me, that was a shock because since I rely on public transportation, I thought most people were like me. Then I started wondering, what percentage of the sample buys public transportation tickets? This is answered in the following graph.

This explains why the median was so low: less than 35% of the families sampled use public transportation.

The previous five plots show that median public transportation and private mobility expenditures have decreased in magnitude since 2020. This could be explained by the deductions in public transportation after COVID-19 and the deductions in petrol following the war in Ukraine.

Finally! How much are we spending in shared mobility?

Similar to public transportation, the majority of Spanish families do not use shared mobility services; hence, the median resulted very low, but checking the mean and removing those with expenses equal to zero delivered the following:

Now, this tells a totally different story than previous graphs. This is the only expenditure that shows growth after COVID-19. It made sense for me as I started using some micro-mobility services, replacing trips that would have been made in public transportation as a way to avoid crowds. This could also be true for other individuals. The cost of 35€ does not seem so high if we consider that these expenses include carsharing and leasing. I checked the median to avoid the influence of higher expenses, but the values were too low, close to 0€. The following plot shows the percentile 75. The percentile 75 is the value that is only surpassed by 25% of the sample. The prices are lower than 25€, which seems reasonable.

Now, let's take a look at shared mobility separately. Car leasing and ridesharing are very different in concept and cost. As we haven’t mentioned car leasing until now, let's see the definition provided by our friend ChatGPT: ‘Car leasing is a financial arrangement in which you pay to use a car for a specific period, typically 2 to 4 years, without owning it. Instead of purchasing the car, you make monthly payments based on its depreciation and interest during the lease term’ (OpenAI, 2024). These monthly payments, usually around hundreds, are very different from monthly Uber expenditures (at least for me). This is why we need to separate them.

The following graph shows the total expenses for ridehailing, taxis, and ridesharing for the sample each year. We see that in 2020, some families spent more than 1000€, but most of the values are below 10€. Actually, the mean for each year is lower than 8€ per month. These values represent me, as my expenses are also around 10€ monthly.

Repeating the analysis with carsharing, leasing, and renting resulted in the following figure:

Figure 15 shows that leasing, renting, and sharing expenses are higher than sharing rides (logically). Here, the maximum exceeds 3500€ per month. However, most values are near zero, with a mean between 20 and 70€ per month between 2018 and 2022.

The graphs presented highlight that our total spending has increased yearly (for car usage, public transportation, and shared mobility). Also, we saw that the percentage of families using public transportation (the cheapest option) is decreasing. So we are spending more on everything; we have our answer right there.

In my case, I'm combining shared mobility with public transportation since I do not own a car. Before, I used public transportation exclusively. I'm now moving more comfortably (nice), spending more cash, and reducing my active mobility (not so nice). Some friends have a car and use shared mobility for trips in the city center to avoid the parking hustle. The following section explores these aspects a little more, comparing households with and without a car.

Who is spending more on shared mobility services? Households with or without a car?

First, let's see what percentage of families use shared mobility.

According to the Spanish National Statistics Institute (INE), Spain comprises approximately 18 million families, give or take. From 2018 to 2022, the number of families reported using shared mobility services oscillated between 5 million and 3 million per year. These numbers constituted the percentages shown in the following chart. They do not represent even half of the total population, as expected.

Now that we know the percentage of families spending on shared mobility let's inspect them in detail.

Geographically, we have a good hint because shared mobility services are present in selected cities in Spain, usually large demographic areas with dense populations. In the previous figure, we saw that almost 27% of families had shared mobility expenses. Using a correlation matrix, let's see what characteristics of these families relate more to using shared mobility: first, ride-sharing, hailing or pooling, and then vehicle leasing and sharing.

The previous matrix shows that the variable that correlates the most to ridehailing and pooling services is the salary, followed by the breadwinners’ education. The impact of salary is logical; I started using Uber, taxis, and other services when I started earning more. However, the impact of education came to me as a surprise; I thought age would have a higher impact than education.

The next matrix also shows salary as the variable most influencing car leasing and sharing.

Finally, a comparison between families owning a car vs. those not. As mentioned before, the idea that shared mobility helps us save money is true if we replace our car trips with shared mobility. However, if we replace our public transportation trips with shared mobility, we will most likely end up spending more (like I am). 

The next graph shows the median expenditure on shared mobility for households with and without a car. The plot shows that households with a car spent more in shared mobility before 2020, and after this year the trend switched. If these families were replacing car trips with shared mobility, they might be saving.

To sum up

Upon delving into the realm of shared mobility services and their different shape and forms, it becomes evident that our transportation expenses have been steadily climbing. While not reaching the levels in 2018, the costs have been on an upward trajectory since 2020. If we are truly in a quest to save, we need to be more conscious of the costs of each trip comparing all options available and choosing wisely.

References

-- OpenAI. (2024). ChatGPT (Mar 14 version) [Large language model]. https://chat.openai.com/chat.

-- Machado, C. A. S., de Salles Hue, N. P. M., Berssaneti, F. T., & Quintanilha, J. A. (2018). An overview of shared mobility. Sustainability, 10(12), 4342.