I had actually never heard of pedestrian level of service, but it appears to be just applying traffic flow modeling principles to pedestrian flow. It is intuitively appealing to me because you can just add pedestrians, cyclists, or whatever mode you want to a transportation model and specify which links in the network are open to which types of “traffic”. Theoretically, you could try to optimize the total flow of people from where they live to the places they need to get to, and not just maximize the flow of motor vehicles. Surely someone must have looked at this. A valid criticism, of course, is that these models can be short-term focused, even looking just at a single weekday peak hour and certainly missing longer-term dynamics like how infrastructure capacity and land use policy affect trip generation over time. Another criticism is that this engineering approach completely misses the quality of life aspects of urban design.

Pedestrian infrastructure assessment: Walkability vs. pedestrian level of service

This paper explores two of the most explored indicators for evaluating pedestrian infrastructure: walkability and Pedestrian Level of Service (PLOS). Walkability, typically used by urban planners, emphasises the qualitative aspects of the built environment, such as safety, comfort, accessibility and aesthetics, whereas PLOS, primarily employed by transport engineers, quantifies the operational performance of infrastructure based on pedestrian flow, density and speed. A systematic PRISMA-based literature review was conducted, covering 60 PLOS studies and 55 walkability studies were analysed in terms of definitions, contributory factors, data collection methods and modeling techniques. Despite sharing the goal of promoting pedestrian-friendly environments, these frameworks differ fundamentally in scope, purpose and methodology and are often applied independently. The findings indicate that walkability indicators vary in how factors are measured and allocated across dimensions. Moreover, walkability is treated as a “static” factor, both conceptually and methodologically. Relatively limited research examines how walkability changes over time (e.g., day vs. night) or varies across population groups. Conversely, PLOS generally excludes socio-spatial dimensions, a choice consistent with its original purpose rather than a methodological limitation. Some approaches attempt to incorporate subjective factors, but usually in ways resembling traditional walkability metrics. This study highlights the need for greater standardization in definitions and assessment frameworks, while also identifying challenges that complicate their practical applicability. Their complementary use can significantly enhance the design, evaluation and planning of pedestrian infrastructure, supporting more livable, sustainable and inclusive cities.