Have you ever walked across a bridge or through an underpass and felt a sudden, inexplicable sense of either safety or profound unease? Perhaps one structure felt welcoming and calm, while a geometrically identical structure nearby made you quicken your pace. That visceral reaction is not random; it is a direct response to a complex web of subtle design cues present in the environment. Urban designers refer to this instantaneous assessment as “perceived safety,” which involves the subjective feelings and assessments users make about their security within a given environment. For decades, this subjective feeling was treated as secondary to “actual safety,” which relied strictly on measurable, objective data points like accident and collision reports.
The essential question that now confronts engineers and city planners is whether that gut feeling of perceived security is merely an emotional response or a critical data point in itself. Emerging research reveals a powerful and often overlooked truth: aesthetics are not a secondary feature or a luxury in infrastructure design; they are, in fact, a core functional requirement with measurable impacts on human behavior and safety outcomes. This fundamental shift compels designers to abandon the purely utilitarian mindset and accept that visual appeal holds significant consequences for public well-being.
The story of contemporary infrastructure is less about simply meeting structural integrity standards and more about managing the psychological relationship between the built environment and the human user. This analysis reveals how the subjective qualities of illumination, cleanliness, harmony, and naturalness fundamentally govern the behavior of drivers and pedestrians alike. Understanding this shift—that design quality demonstrably affects crash rates and determines who feels secure enough to use infrastructure—forces cities to prioritize budgeting and planning in a way that integrates psychological insight directly with structural engineering.
I. Foundation and Mechanism: The Metrics of Calm
To truly grasp the functional role of beauty, we must first distinguish between the primary safety metrics. Perceived safety refers to the subjective feelings and assessments of users regarding their security, typically measured through surveys assessing factors like built-environment characteristics and design elements. Conversely, actual safety relates to measurable outcomes, such as the incidence of traffic collisions, which is influenced by user behavior and risk perception. The critical insight is that the former consistently drives the latter.
Research consistently points to something more human-scale than imposing grandeur as the key drivers of perceived safety. The factors that have the biggest impact are remarkably practical: good illumination, cleanliness, and proper infrastructure maintenance are key environmental components that contribute to feelings of safety, reassurance, and security on bridges and streets. Visually appealing, well-cared-for spaces subconsciously encourage a calmer and more attentive disposition from users, which promotes safety by reducing reckless behavior. Clean and well-lit environments are consistently associated with higher perceived security and reassurance for users.
Beyond basic upkeep, a higher-order design intelligence plays a crucial role in establishing security. Principles like good proportions, harmony, and coherence are significant drivers of a bridge’s aesthetic appeal, and consequently, the resulting sense of security it provides. Public preference tends toward bridges with well-proportioned components that harmonize with their surroundings, enhancing both beauty and safety perception.
Furthermore, designers are finding immense functional value in biophilic design—the practice of incorporating natural forms, materials, and greenery into built spaces. When architecture mimics forms found in nature, following biophilic principles, people report feeling a closer relationship, greater comfort, and higher perceived safety. Perceived naturalness is a primary determinant of aesthetic appeal in infrastructure projects, and it is closely linked to positive safety perceptions. Conversely, harsh, grey architecture and poorly maintained areas evoke unease and can lead to feelings of isolation or loneliness, actively diminishing safety perception. Simpleness, brightness, and calmness are influential variables in aesthetic perception, while damaged infrastructure detracts from both beauty and perceived safety.
II. The Crucible of Context: The Gendered Perception of the Span
While the physical mechanisms of lighting and cleanliness are universal, the perception of the built environment is not; it is profoundly shaped by an individual’s identity, emotional responses, and lived experiences. This non-universal experience introduces the primary complicating factor in design.
One of the most critical findings in safety research is the stark gender disparity in how bridges and elements of the built environment are perceived. Research has revealed that the presence of bridges may positively influence safety perception among men but often has the exact opposite effect on women. This significant difference is not just statistical noise; researchers suggest it may stem from “differences in emotional responses and driving affinity”.
This insight highlights a fundamental miscalculation inherent in the historic pursuit of one-size-fits-all design. An environment is only as safe as it feels to its most vulnerable users. Where one individual sees a convenient crossing and feels assured by the engineering scale, another might perceive an unmonitored, exposed, or enclosed space that suggests a potential threat. Truly safe cities must be designed with an explicit understanding of these varied perspectives. For example, emotional responses such as dread or anxiety, particularly in contexts with high crime rates, can significantly outweigh general safety attitudes and influence a pedestrian’s decision about whether to use safe infrastructure, such as a footbridge. This realization demands that engineers and urban planners integrate empathy and behavioral psychology into their calculations, ensuring that the infrastructure feels secure for everyone, acknowledging that visually appealing and navigable spaces are also perceived as more inclusive.
III. The Cascade of Effects: The Paradox of Superficial Upgrades
The synthesis of these findings leads to a powerful conclusion regarding actual safety outcomes. Studies have found that streets and bridges which receive high “beauty scores” are associated with fewer traffic crashes, strongly suggesting that aesthetic improvements can yield tangible, objective safety benefits. The visual appeal of a space—its harmony, coherence, and natural elements—reframes beauty not as mere decoration but as a critical component of safe infrastructure.
However, this association is complicated by a fascinating and counter-intuitive twist: the paradox of superficial upgrades. While beautiful streets are generally linked to fewer accidents, one study uncovered that renovations aimed solely at improving what researchers measured as a street’s “depressing” score sometimes led to an increase in traffic crashes.
This paradox reveals a critical distinction between deep, functional design and superficial aesthetic interventions. The increase in crash frequency occurred because the cosmetic fixes created a false sense of security; if a renovation makes a road look and feel safer without integrating corresponding functional safety measures (such as better crosswalks or traffic calming), drivers and pedestrians may inadvertently behave less cautiously. Essentially, the feeling of safety outpaced the reality of the engineering. The lesson for cities and designers is clear: cosmetic fixes can be dangerous, as they risk masking underlying risks and encouraging riskier behavior. True safety emerges when aesthetic improvements are deeply integrated with functional design that actively guides safer behavior, ensuring that practicality and aesthetics align within the infrastructure. Successful bridge design requires carefully balancing safety, functionality, cost, and aesthetic harmony with the surrounding environment, reinforcing that aesthetics should be integral to the process, not an afterthought.
IV. Synthesis and Implications
For too long, the aesthetic quality of our public infrastructure has been treated as an afterthought—a rounding error in a budget focused purely on function. The accumulating evidence on safety and behavior confirms that this mindset is a critical miscalculation.
The crucial insight is that the public’s perception, driven by fundamental sensory inputs like good illumination, cleanliness, naturalness, and harmonious design, dictates user behavior, which in turn drives actual safety outcomes. When infrastructure design fails to address these psychological needs, it fails structurally in the broadest sense. Effective design, therefore, must embrace the idea that beauty, harmony, and thoughtful composition are functional components of public safety and well-being. The way a place makes us feel directly influences how we behave within it. This data demands that planners see aesthetics as integral to their mission, rather than a luxury addition.
The initial gut feeling of safety or unease is not merely a subjective emotion; it is a distillation of complex environmental data points—a cognitive warning system refined by subtle design cues. The future of resilient urban engineering lies in abandoning the purely utilitarian mandate and embracing the analytical rigor needed to achieve coherence, beauty, and inclusivity. Thoughtful design, which integrates aesthetics with critical functional safety features, proves to be the most effective safety measure of all.
Referemces
References
Blumentrath, C., & Tveit, M. (2014). Visual characteristics of roads: A literature review of people’s perception and Norwegian design practice. Transportation Research Part A: Policy and Practice, 59. https://doi.org/10.1016/j.tra.2013.10.024
Cantillo, V., Arellana, J., & Rolong, M. (2015). Modelling pedestrian crossing behaviour in urban roads: A latent variable approach. Transportation Research Part F: Traffic Psychology and Behaviour, 32. https://doi.org/10.1016/j.trf.2015.04.008
Cui, Q., Zhang, Y., Yang, G., Huang, Y., & Chen, Y. (2023). Analysing gender differences in the perceived safety from street view imagery. International Journal of Applied Earth Observation and Geoinformation, 124. https://doi.org/10.1016/j.jag.2023.103537
El-Metwally, Y., Khalifa, M., & Elshater, A. (2021). Quantitative study for applying prospect-refuge theory on perceived safety in Al-Azhar Park, Egypt. Ain Shams Engineering Journal, 12. https://doi.org/10.1016/j.asej.2021.04.016
Häussermann, F., Gryp, D., Schepers, W., Dikmans, B., Dury, S., & De Donder, L. (2026). How the neighbourhood-built environment shapes loneliness: A photo-elicitation study. Health & Place, 97. https://doi.org/10.1016/j.healthplace.2025.103587
Ihssian, A., & Ismail, K. (2023). Modelling pedestrian safety at urban intersections using user perception. Accident Analysis & Prevention, 180. https://doi.org/10.1016/j.aap.2022.106912
Kaynarkaya, S., Çekmiş, A., Çetin, İ., Şahin, Y., & Ünal, G. (2025). Assessing walkability with deep CNNs by integrating objective and subjective urban qualities: The case of ‘Cittaslow’ neighborhoods. Sustainable Cities and Society, 133. https://doi.org/10.1016/j.scs.2025.106863
Landa-Blanco, M., & Ávila, J. (2020). Factors related to the use of pedestrian bridges in university students of Honduras. Transportation Research Part F: Traffic Psychology and Behaviour, 71. https://doi.org/10.1016/j.trf.2020.04.016
Li, J., Yang, S., Hao, J., Gao, G., Wang, F., Bai, H., Zhao, G., Li, Y., & Xue, X. (2024). Advances and applications of wind engineering in exceptional terrain. Journal of Traffic and Transportation Engineering (English Edition), 11. https://doi.org/10.1016/j.jtte.2024.09.002
Liu, Y., Chen, T., Chung, H., Jang, K., & Xu, P. (2025). Is there an emotional dimension to road safety? A spatial analysis for traffic crashes considering streetscape perception and built environment. Analytic Methods in Accident Research, 46. https://doi.org/10.1016/j.amar.2025.100374
McCormick, A., Fisher, K., & Brierley, G. (2015). Quantitative assessment of the relationships among ecological, morphological and aesthetic values in a river rehabilitation initiative. Journal of Environmental Management, 153. https://doi.org/10.1016/j.jenvman.2014.11.025
Mushkani, R., & Koseki, S. (2026). Street review: A participatory AI-based framework for assessing streetscape inclusivity. Cities, 170. https://doi.org/10.1016/j.cities.2025.106602
Oliveira Pedro, J., & Reis, A. (2010). Nonlinear analysis of composite steel–concrete cable-stayed bridges. Engineering Structures, 32. https://doi.org/10.1016/j.engstruct.2010.04.041
Oviedo-Trespalacios, O., & Scott-Parker, B. (2017). Footbridge usage in high-traffic flow highways: The intersection of safety and security in pedestrian decision-making. Transportation Research Part F: Traffic Psychology and Behaviour, 49. https://doi.org/10.1016/j.trf.2017.06.010
Sadeghi, S., Mahmoudi Kamelabad, M., Kamelnia, H., & Hoseinpour Jajarm, M. (2025). Quantitative assessment model for spatial and functional performances of structures using fuzzy logic, case studies: Spaceframe structures. Structures, 74. https://doi.org/10.1016/j.istruc.2025.108605
Tang, M. (2018). Forms and Aesthetics of Bridges. Engineering, 4. https://doi.org/10.1016/j.eng.2017.12.013