Opinion – Claudio Bernardes: The dynamics of pedestrian traffic

As cities look for human-scale development models –and the activity of walking through urban space gains relevance–, investigating the dynamics of pedestrian traffic becomes an extremely significant issue.

Understanding the movement of pedestrians in real environments, in situations of multidirectional spatial behavior, and the evaluation of the relationships between speed, density and flow in walking journeys allows designing pedestrian structures with desirable safety and efficiency.

For this purpose, Hong Kong can be considered an open-air laboratory, as it offers the opportunity to examine pedestrian dynamics in relatively dense conditions. Professor John Zacharias, from the Urban Process Modeling Laboratory at Peking University, China, published a study on pedestrian dynamics in places with a high density of pedestrians in the city.

To prepare the study, data were collected on a sample of 24 road environments, with different widths of sidewalks and pedestrian flow. Individual trajectories of 356 randomly selected people were extracted from video recordings. Pedestrian speed was related to the following independent variables: pedestrian volume, pavement width, effective pavement width and the existence of shops along the route. The eventual formation of flow lanes and counterflows was identified and measured. To examine how the street environment compares to the free-flow conditions of wider, dedicated corridors, travel speed was measured for 356 randomly selected individuals in seven dedicated corridors for access to the subway transport system.

The results showed that the parameters, displacements, effective width of the space for displacement, number of stores and sex, evaluated together, were responsible for 13.7% of the variation in flow velocity, while the volume of pedestrians was not significant. A slight trend of movement to the right was observed in bidirectional flows.

The study concluded that walking speed on Hong Kong streets is limited by shopping activity, obstacles and reduced spatial dimensions. Walking speed is maintained through displacement, with higher speeds at the outer edge of the pedestrian space.
As expected, it became clear that people walk significantly faster in dedicated aisles.

Exploiting the full potential of pedestrian infrastructure is becoming a critical step in many environments that cannot easily expand to handle increased flow. This is particularly true in certain locations such as train stations, accesses to high-concentration and dedicated public spaces. Also, in many cities with limited space and where expansion would be difficult and very expensive.

Researchers from the transport and mobility laboratory at the Federal Polytechnic School of Lausanne, Switzerland, sought to study models aimed at improving the level of service experienced by pedestrians by regulating and controlling their movements with a dynamic traffic management system. Although dynamic traffic management systems have been extensively investigated over the past two decades to mitigate vehicular traffic congestion, little attention has been paid to dynamic traffic management systems for pedestrian flows.

The researchers propose a general framework for dynamic traffic management systems that consider the specifics of pedestrian traffic. The study illustrates this structure using a control strategy designed for pedestrian flows, which mitigates the problems induced by bidirectional flows, one of the primary issues in pedestrian movement. The results emphasize the under-exploited potential of pedestrian control and guidance when integrated into a dynamic management system.

Pedestrians are distinguished by a number of key characteristics, such as personal choice, variable dynamics and vulnerability. The understanding of this process, combined with the urban infrastructure project to improve the performance of people walking, will certainly bring very positive influences, capable of improving life in cities.