A ladder of measures against overcrowding

What the study finds

• The model arranges five types of intervention in order of increasing intensity: neutral information, nudges and recommendations, pricing, reservation and, as a last-resort emergency step, closing access.
• The authors define visitor pressure as the number of people per unit of time or space, relative to the place's designated capacity; it follows that the same number of visitors weighs more when concentrated in a short time or a small area.
• According to the model, information alone, even on real-time crowding, only works when visitors are very willing to change plans and pressure is low; when pressure is high and willingness is low, the next step is nudges and recommendations, then stronger measures.
• Reservation is presented as potentially very effective, since only those who have booked get in, but it requires physical access-control systems and digital platforms; the authors suggest that after three years of pandemic most visitors are used to such procedures.
• Among examples of digital tools in use, the authors cite a Dubrovnik app that forecasts tourist numbers using cruise arrivals among other inputs, and a Palma de Mallorca app designed to spread out cruise passengers using data from the port and city Wi-Fi network.
• The authors state that the model does not rest on empirical evaluations, because none exist, and offer it as a guide for future evaluation; they also note that no recommender system yet exists that uses sensor data on crowding at points of interest.