Developing Streetscape Design Scenarios for Reducing Perceived Stress and Enhancing the Psychological Restorative Capacity of Street Environments-The Case of Shariati Street, Tehran

Introduction:
Urban streets shape physical, social, sensory, and visual experiences. On high-traffic streets, traffic, noise, crowding, conflicts, visual disorder, and limited rest may increase stress and reduce psychological restoration, while vegetation, shade, seating, safety, legibility, and visual coherence may support it. Restorative quality also depends on how these elements interact with pedestrian comfort and environmental pressures, and may vary among users and along the street. This study examines a section of Shariati Street in Tehran, from Qods Square to the intersection of Rezaei and Mousivand streets.
The Purpose of the Research:
The main purpose of the study was to identify the perceptual structure of environmental stress and psychological restorative capacity among street users and to translate perceptual and spatial findings into place-based streetscape design scenarios. The study aimed to identify the main dimensions of perceived stress and restoration, distinguish different patterns of user experience, examine the spatial distribution of environmental pressures and restorative capacities, and develop streetscape design scenarios responsive to both user differences and local spatial conditions.
Methodology:
This applied, descriptive–analytical study used a mixed-methods approach. Data was collected through documentary studies, field observations, perceptual mapping, and a researcher-developed 20-item questionnaire. The study population included pedestrians, residents, shopkeepers, private-vehicle users, and public-transport users. A total of 150 participants were selected through non-probability sampling using a combination of purposive and quota sampling. Data collection was conducted at different times of the day and on weekdays and weekends. Content validity was reviewed by specialists in landscape architecture and urban design, and the internal consistency of the questionnaire was satisfactory, with Cronbach’s alpha coefficient of 0.894. Principal Component Analysis (PCA) with varimax rotation was used to identify the underlying perceptual structure. Sampling adequacy was examined using the Kaiser–Meyer–Olkin index and Bartlett’s test of sphericity. Standardized component scores were then used in K-means cluster analysis to identify exploratory patterns of user experience. The statistical findings were integrated with perceptual mapping and field observations to identify spatial concentrations of environmental pressure and restorative capacities. Based on these findings, three place-based streetscape design scenarios were developed and compared qualitatively.
Findings and Discussion:
The findings showed that noise pollution was the strongest perceived environmental stressor, with a mean score of 4.41, followed by high traffic density and vehicle speed (4.31) and lack of benches or suitable resting places (4.24). Among restorative qualities, social presence and vitality had a mean of 4.13, trees and green spaces 4.10, and water elements 4.09. The KMO value was 0.64, and Bartlett’s test was statistically significant, supporting PCA. Five components were extracted, explaining 76% of the total variance: environmental–health burden, nature-based restoration, legibility, control and perceived safety, movement pressure and quality of social presence, and place attachment and visual quality. Environmental–health burden accounted for 34.36% of the variance and showed an interconnected pattern of traffic, noise, fatigue, and perceived health-related consequences. The findings also indicated that the restorative potential of natural elements depended on shade, seating, pedestrian continuity, and some separation from traffic and noise. K-means clustering identified three exploratory user-experience patterns. The first cluster included 15 participants (10%) and showed a stronger need for nature-based restoration and greater sensitivity to visual and movement-related disorders. The second included 57 participants (38%) and showed a comparatively higher environmental–health burden, while the third included 78 participants (52%) and showed lower perceived stress, although a need for general environmental improvement remained. These patterns suggest that a single “average user” may not adequately reflect differences in user experience; however, the clusters should be interpreted as exploratory patterns within the study sample rather than fixed user types.
The integration of statistical results, perceptual mapping, and field observations showed that environmental pressures were unevenly distributed. Around Qods Square, pedestrian crowding and visual disorder were more apparent, while the central section showed the greatest overlap of noise, traffic density, pedestrian–vehicle conflicts, insufficient resting opportunities, and visual disorder and was identified as the main intervention priority. Three streetscape design scenarios were developed: the “restorative–refuge landscape,” emphasizing nature-based restoration, safety, resting areas, and reduced traffic exposure; the “calm and dynamic landscape,” focusing on visual coherence, facade and signage organization, spatial legibility, and reduced visual and movement-related disorder; and the “integrated–combined landscape,” combining the strengths of both approaches according to spatial conditions. The integrated–combined scenario provided the most comprehensive response because of its spatial flexibility, allowing traffic- and noise-exposed areas to prioritize movement management, green filtering, separation from vehicular flows, and resting opportunities, while visually disordered areas could emphasize facade organization, visual coherence, and legibility.
 Conclusion:
The findings show that perceived stress in high-traffic urban streets is a multidimensional experience shaped by environmental, spatial, sensory, social, and perceptual conditions. Improving psychological restorative capacity therefore requires more than increasing greenery or applying beautification measures. It requires coordinated attention to traffic and noise exposure, pedestrian movement, opportunities for rest, spatial legibility, perceived safety, visual quality, and usable natural elements. The main contribution of this research is an analytical process that connects perceptual components, exploratory user patterns, and spatial concentrations of environmental pressure with place-based streetscape design scenarios. The integrated–combined scenario was identified as the most suitable option within the qualitative comparison, although this should not be interpreted as evidence of actual stress reduction after implementation. Future studies should evaluate the proposed interventions through before-and-after assessments and objective environmental measurements.