RATP: Improving cleanliness in the Parisian metro and RER train stations


Especially as many of us shift out of our COVID-19 lockdowns and into our “new normal”, the issue of cleanliness in public places and especially in public transport goes beyond cleaning problems and comes both under cleaning staff’s efficacy and public civility.

Cleanliness is at the top of RATP’s (the Autonomous Parisian Transportation Administration) priorities. However, a survey conducted in France by BVA (2017) shows that only 4 out of 10 people were satisfied with cleanliness in public transport in France. RATP therefore wanted to innovate by using behavioral science to supplement their actions and improve its customers’ experience.

This desire is reflected by a whole series of nudges implemented in major Parisian stations to draw attention to bins and to the work done by RATP, in order to encourage good behavior.

Cleanliness in the public place: an ideal field of action for behavioral science and nudge

Cleanliness is a universal and key subject for which nudge and behavioral science have already proven to be effective. An example: green steps towards bins reduced waste on the ground in Copenhagen by 46%. 

But what is a Nudge? It is a little help, or intervention, that creates an architecture of choice and encourages individuals to adopt virtuous behaviors without constraint (Thaler and Sustein, 2008). How does it work? By acting on what we know about our behaviors – that are actually irrational, systematic and predictable (Ariely, 2008). Indeed, we are constantly influenced when making decisions and most often, unconsciously: by our emotions, our habits, others, and especially by many cognitive biases (Kahneman, 2011).

Why apply behavioral science and nudge to improve cleanliness in public places? Because it is very effective in accelerating the shift towards virtuous behavior when laws, information or financial incentives show their limits; and because it is a subject where legitimacy is strong and the intention to act, or at least to enjoy a clean environment, is real.

Using a nudge approach at RATP on the issue of cleanliness: an approach that is part of an innovation tradition on a priority issue

The issue of cleanliness is a real challenge for RATP who sees 12 million passengers passing through its 368 metro and RER train stations every day.

On October 16, 2018, a specific plan to improve the cleanliness of the network operated by RATP was presented. The objective: to implement new actions, including the so-called “nudge approach”.

RATP called on the BVA Nudge Consulting to set up some nudge measures. We helped to encourage passengers to adopt ideal behavior regarding cleanliness in stations by using the right and available equipment to throw out their waste. For this, a multi-step nudge approach was proposed: the ICTA method – Identify – Create – Test – Adapt.

The ICTA method (Identify – Create – Test – Adapt):

1. Identify: Identify all the cognitive biases, obstacles, and levers for the ideal behaviors.

Why? Because relevant levers for change can only be found when the real motives that drive people to do what they do, when they do it, and how they do it, are known.

How? With an ethnographic study completed by individual flash interviews.

2. Create: Create nudges during a collaborative creative workshop to remove the identified obstacles.

How? By bringing together different people with different backgrounds in order to boost creativity and collective intelligence.

Of the 120 nudge ideas that emerged from this workshop, 22 were pre-selected and finally, 6 were selected to be prototyped and tested.

3. Test: Test the nudges to verify their effectiveness.

Why? To check the impact of the approach, which must have a positive effect on behavior.

How? With a before / after the installation of the nudges test method. After 2 months of implementation, a quantitative study, a qualitative and ethnographic study, as well as a comparison with mystery customer surveys’ results were carried out.

4. Adapt: Adapt the nudges according to the lessons learned from the test phase.

Why? To improve effectiveness, practical use on a daily basis, and optimize costs for industrialization.

How? By reviewing graphics and the wording of some of the nudges.

In practice, half a dozen nudges were set up

These nudges were based on 5 main principles from the work matrix we use called the Drivers of Influence, designed by BVA, with each letter being an acronym of a major decision-making bias (Singler, 2015).

  • Salience: graphics on bins and ashtrays to draw attention.


  • Value: entertaining “True or true?” mosaic boards providing information on the technical interventions carried out on a daily basis to make customer experience more pleasant.
  • Emotion and reciprocity: RATP employee figurations at station entrances to welcome clients and embody human presence, distinguishing the outdoors spaces from those of the station.
  • Reinforcement: thank you messages intended for passengers (on the bins, at station exists) to show some recognition.

What were the results and the assessment of this nudge experiment?

Several positive impacts have been noted, including:

  • The nudges are visible and have a strong impact: the usage rate of bins and ashtrays doubled, along with a reduction of waste on the ground.
  • The nudges were factors of delight: 9 out of 10 customers were satisfied with the cleanliness of stations, which contributes to convey a positive image of the RATP company

One limitation was also noted: the visibility and the impact of the nudges differed depending on the stations, including:

  • External elements that interfere with the experience such as maintenance work.
  • Some stations’ space configuration that make it impossible for some of the nudges to be installed.

In conclusion

These nudges will be deployed in 30 to 40 Parisian metro and RER train stations.

RATP is thinking about using these methods to address other issues, such as civility in public transportation, which is a fertile ground for drawing on behavioral sciences and nudge.