Reconciling Urban Density with Daylight Equity in Sloped Cities: A Case for Adaptive Setbacks in Amman, Jordan

Abstract

Urban regulations in Amman, Jordan, enforce uniform building setbacks irrespective of topography, exacerbating shading effects and compromising daylight access in residential areas—a critical factor for occupant health and psychological well-being. This study evaluates the interplay between standardized setbacks, slope variations (0–30%), and shadow patterns in Amman’s dense, mountainous urban fabric. Focusing on the Al Jubayhah district, a mixed-methods approach was used, combining field surveys, 3D modeling (Revit), and seasonal shadow simulations (March, September, December) to quantify daylight deprivation. The results reveal severe shading in winter (78.3% site coverage in December) and identify slope-dependent setbacks as a key determinant: for instance, a 15 m building on a 30% slope requires a 26.4 m rear setback to mitigate shadows, compared to 13.8 m on flat terrain. Over 39% of basements in the study area remain permanently shaded due to retaining walls, correlating with poor living conditions. The findings challenge Amman’s one-size-fits-all regulatory framework (Building Code No. 67, 1979), and we propose adaptive guidelines, including slope-adjusted setbacks, restricted basement usage, and optimized street orientation. This research underscores the urgency of context-sensitive urban policies in mountainous cities to balance developmental density with daylight equity, offering a replicable methodology for similar Mediterranean climates.

1. Introduction

Urban design guidelines often assume flat terrain, neglecting the complexities of mountainous, semi-arid cities like Amman, Jordan. This study addresses this gap by investigating slope-adjusted setbacks, employing advanced 3D modeling (Revit) and seasonal shadow simulations to quantify daylight deprivation—a novel approach in the context of Middle Eastern cities. By challenging the outdated ‘one-size-fits-all’ policy of Building Code No. 67, 1979, this research proposes adaptive guidelines tailored to Amman’s topography, offering a framework for equitable urban development in similar regions. The findings not only highlight the limitations of uniform setbacks in sloped terrains but also provide actionable insights for policymakers and urban planners.

Despite Amman city being characterized by abundant sunshine, with an average daily global radiation of 5.7 kWh/m² [1], the exposure of residential units to daylight varies significantly due to factors such as floor level, orientation, and external obstructions [2]. The quality and quantity of daylight entering a building hinge on a combination of interior and exterior elements, including the percentage of glazing, type of glass, shelter usage, building height, distance between blocks, topography, interior painting, room size [3], and the color and texture of materials in the space [4]. In cities with mountainous terrains, daylight access transcends architectural design, and it becomes a determinant of public health and social equity. Amman, Jordan, a rapidly growing city nestled in a semi-arid, sloped landscape, exemplifies this challenge. Despite its average daily solar radiation of 5.7 kWh/m², over 23% of residential buildings in districts like Al Jubayhah suffer from year-round shading due to the rigid application of *[Building Code No. 67, 1979]. This code mandates uniform setbacks (e.g., 4–7 m) across all residential zones, disregarding slope variations that amplify shadow lengths and trap basements in perpetual darkness. While global studies emphasize daylight’s role in circadian rhythm regulation and psychological well-being, research in Middle Eastern cities—particularly those with Amman’s geo-climatic profile—remains sparse.

This paper addresses this gap by investigating how slope-adjusted setbacks could mitigate shading while maintaining urban density. Focusing on Al Jubayhah (slopes: 0–30%), we employ 3D shadow simulations (Revit) and field surveys to analyze seasonal shading patterns across 250 buildings. The results reveal that sloped lots require setbacks up to 2.1× larger than flat terrain to prevent shading, with 39.6% of basements failing daylight standards due to retaining walls. By proposing adaptive regulations, such as dynamic setbacks tied to slope percentages and restrictions on basement habitation, this study challenges the one-size-fits-all paradigm of Amman’s urban policy. The findings aim to inspire regulatory frameworks that harmonize urban growth with environmental and human well-being in topographically complex cities.

2. Literature Review

2.1. Importance of Daylight in Urban Environments

2.1.1. Health and Psychological Benefits

Daylight exposure plays a critical role in human health and well-being, influencing both physical and psychological outcomes. Research by [5] highlights the importance of natural light in regulating circadian rhythms, which govern sleep–wake cycles and overall physiological functioning. Similarly, ref. [6] emphasize that adequate daylight exposure can mitigate the risk of vitamin D deficiency, a condition linked to weakened immunity and bone health. Beyond physical health, daylight has been shown to enhance mental well-being by reducing symptoms of depression and anxiety, particularly in urban environments where residents spend the majority of their time indoors. Conversely, inadequate daylight exposure has been associated with seasonal affective disorder (SAD), a form of depression triggered by prolonged periods of low light, as well as increased reliance on artificial lighting, which can disrupt sleep patterns and contribute to chronic fatigue [7]. These findings underscore the necessity of integrating daylight access into urban planning to promote healthier living environments.

Recent studies have emphasized the importance of daylight equity in promoting urban health, particularly in topographically complex regions. For example, ref. [8] investigated the relationship between daylight access and mental health in mountainous cities, finding that inadequate daylight exposure in sloped areas correlates with higher rates of seasonal affective disorder (SAD) and stress-related illnesses. Similarly, ref. [9] highlighted the disproportionate impact of poor daylight access on lower-income neighborhoods in hilly urban areas, underscoring the need for equitable urban design policies. These findings align with our study’s focus on Amman, where slope-induced shading exacerbates daylight deprivation in densely populated, low-income areas.

2.1.2. Energy Efficiency

Daylight is not only essential for human health but is also a cornerstone of energy-efficient building design. Studies by [10] demonstrate that optimizing natural light in residential and commercial spaces can significantly reduce energy consumption for lighting and heating, thereby lowering carbon footprints and operational costs. Passive solar design, which leverages building orientation, window placement, and shading devices to maximize daylight penetration, has been widely recognized as a sustainable strategy for urban development [11]. For instance, in Mediterranean climates like Amman’s, well-designed daylighting systems can minimize the need for artificial lighting during the day and reduce cooling loads by preventing excessive heat gain. However, the effectiveness of such strategies depends on careful consideration of local climatic and topographical conditions, as well as adherence to building codes that prioritize daylight access. These insights highlight the dual benefits of daylighting: enhancing occupant comfort while advancing global sustainability goals.

The intersection of energy efficiency and social equity has gained significant attention in recent urban planning research. A study by [12] demonstrated that slope-sensitive building regulations can reduce energy consumption by optimizing daylight penetration, particularly in residential buildings. Their findings suggest that adaptive setbacks on sloped terrains can decrease reliance on artificial lighting by up to 30%, benefiting both energy efficiency and occupant well-being. Additionally, ref. [13] explored the social equity implications of urban design, arguing that uniform building codes often neglect the needs of marginalized communities in topographically challenging areas. These insights reinforce the importance of revising outdated policies like Building Code No. 67, 1979, to address both energy and equity concerns.

2.1.3. Social Equity

Access to daylight is not evenly distributed across urban populations, often reflecting broader socioeconomic disparities. In dense urban areas, lower-income households are more likely to reside in poorly designed buildings with limited access to natural light, exacerbating health inequalities [14]. For example, basements and ground-floor apartments in high-density neighborhoods are particularly prone to shading, resulting in dim, uninhabitable spaces that disproportionately affect vulnerable populations. Furthermore, the lack of enforceable regulations on daylight access in many cities perpetuates these inequities, as developers prioritize profit over livability. Addressing these issues requires a holistic approach that integrates daylight equity into urban policy, ensuring that all residents, regardless of socioeconomic status, have access to spaces that promote health and well-being. This is especially critical in cities like Amman, where rapid urbanization and economic pressures have led to the proliferation of substandard housing in shaded, sloped areas.

2.2. Urban Regulations and Daylight Access

2.2.1. Global Perspectives

Urban planning codes in cities with similar topographies, such as San Francisco and Hong Kong, provide valuable insights into addressing daylight access in sloped environments. San Francisco’s Sunlight Ordinance mandates that new developments minimize shading on public spaces and neighboring properties, ensuring equitable access to natural light even in its hilly terrain [15]. Similarly, Hong Kong’s Building (Planning) Regulations incorporate slope-specific guidelines, requiring larger setbacks for buildings on steep gradients to prevent excessive shading [16]. These examples demonstrate that slope-sensitive regulations can balance urban density with daylight equity, offering a model for cities like Amman. However, the effectiveness of such policies depends on rigorous enforcement and community engagement, as well as the integration of advanced simulation tools to predict shading impacts during the design phase. By learning from these global case studies, Amman can develop adaptive regulations that address its unique topographical challenges while promoting sustainable urban growth.

Recent advancements in urban design have highlighted the need for slope-sensitive regulations to address the unique challenges of mountainous cities. For instance, ref. [17] proposed a framework for integrating slope-specific guidelines into urban planning policies, emphasizing the importance of context-sensitive design in promoting sustainable development. These studies provide a strong foundation for our research, which seeks to develop adaptive guidelines tailored to Amman’s topography.

2.2.2. Middle Eastern Context

The Middle East, with its semi-arid climate and rugged terrains, presents unique challenges for daylight access in urban areas. Despite the region’s abundance of sunlight, rapid urbanization and high-density development have led to widespread shading issues, particularly in cities like Amman, Beirut, and Riyadh. Research on daylight access in these contexts remains limited, with most studies focusing on thermal comfort and energy efficiency rather than the psychological and social impacts of shading [18]. For instance, in Amman, the combination of steep slopes and uniform building codes has resulted in densely packed neighborhoods where lower floors and basements are often deprived of natural light. This lack of attention to daylight equity reflects a broader gap in urban policy research, highlighting the need for context-specific studies that address the interplay between topography, climate, and urban form in Middle Eastern cities.

2.2.3. Amman’s Regulatory Framework

Amman’s Building Code No. 67, 1979 exemplifies the limitations of uniform urban regulations in topographically diverse cities. The code mandates fixed setbacks (e.g., 4–7 m) across all residential zones (see

Table 1. Characteristics of residential areas.

Residential Zone	Plot Area/m2	Percentage of Footprint	Front Setback/m	Side Setback/m	Rear Setback/m
A	1000	39%	5	5	7
B	750	45%	4	4	6
C	500	51%	4	3	4
D	300	55%	3	2.5	2.5

Source: [19].

), regardless of slope variations, leading to significant disparities in daylight access. For example, in sloped areas like Al Jubayhah, buildings with identical setbacks cast longer shadows than those on flat terrain, resulting in chronic shading for neighboring properties and lower floors [1]. Furthermore, the code’s lack of provisions for basement illumination has exacerbated the problem, with many basements in Amman remaining uninhabitable due to poor daylight conditions. Studies on Amman’s urban sprawl have criticized these regulations for prioritizing economic growth over livability, calling for reforms that incorporate slope-sensitive guidelines and advanced simulation tools to optimize daylight acces) [19]. Addressing these shortcomings is essential for creating equitable, sustainable urban environments in Amman and similar cities.

2.3. Critique of Building Code No. 67, 1979

Building Code No. 67, 1979, established uniform setback requirements (e.g., 4–7 m) without considering the complexities of sloped terrains. Developed during a period of rapid urbanization, the code reflects a ‘one-size-fits-all’ approach that fails to address the unique challenges of mountainous cities like Amman. Our simulations reveal that uniform setbacks, when applied to sloped terrains, exacerbate shading by increasing the effective height of buildings. For instance, on a 20% slope, shadows extend up to 25 m, compared to 10 m on flat terrain. This results in basements and lower floors being trapped in perpetual darkness, particularly in densely built neighborhoods.

The lack of slope-sensitive guidelines in Building Code No. 67, 1979, disproportionately affects lower-income neighborhoods, which are frequently situated on steeper slopes. Our findings show that residential units in these areas experience daylight factors as low as 1.2%, compared to 2.5% in flatter, wealthier neighborhoods. This inequity underscores the need for policy reforms that prioritize equitable daylight access. Furthermore, the perpetual darkness caused by excessive shading in sloped areas not only reduces livability but also increases energy consumption, as residents rely heavily on artificial lighting. Inadequate daylight access has also been linked to adverse health outcomes, including increased stress and reduced productivity.

Considering these findings, we advocate for the revision of Building Code No. 67, 1979, to incorporate slope-adjusted setbacks and other context-specific guidelines. Such reforms would ensure equitable daylight access, improve urban livability, and promote sustainable development in Amman and similar cities.

2.4. Shadow Analysis and Simulation Tools

2.4.1. Shadow Dynamics

Shadow patterns in urban environments are influenced by a complex interplay of building height, orientation, and spacing. Ref. [2] highlights that taller buildings cast longer shadows, particularly when clustered in high-density areas, while building orientation determines the direction and extent of shading throughout the day. For instance, south-facing buildings in the Northern Hemisphere receive more sunlight, whereas north-facing structures are prone to prolonged shading. Seasonal variations in solar geometry further complicate these dynamics, with lower sun angles in winter producing longer shadows compared to summer [20]. In cities like Amman, where steep slopes exacerbate these effects, understanding shadow dynamics is critical for optimizing daylight access. By analyzing these factors, urban planners can design layouts that minimize shading while maintaining density, ensuring equitable access to natural light across all seasons.

2.4.2. Simulation Tools

Advancements in simulation tools have revolutionized the analysis of daylight and shadow patterns in urban environments. Software like Revit 2018, AutoCAD 2018, and ClimateStudio enable precise modeling of building geometries, solar paths, and shadow impacts, providing valuable insights for urban design and policy. For example, Revit’s solar analysis tools allow planners to visualize shadow patterns at different times of the year, while ClimateStudio offers advanced daylighting metrics such as spatial daylight autonomy (sDA) and annual sunlight exposure (ASE) [21]. These tools have been successfully used in cities like San Francisco and Copenhagen to inform building codes and zoning regulations, ensuring that new developments maximize daylight access without compromising urban density [10]. By leveraging these technologies, Amman can develop data-driven policies that address its unique topographical and climatic challenges, setting a precedent for other cities in the region.

2.4.3. Topographical Considerations

Topography plays a critical role in shaping shadow patterns, particularly in cities with significant elevation changes like Amman. Slope gradients amplify shading effects by altering the angle and length of shadows, with steeper slopes producing longer shadows that disproportionately affect lower floors and basements [2]. Retaining walls, commonly used in sloped areas to stabilize terrain, further exacerbates the problem by blocking daylight from adjacent buildings. Studies have shown that basements in sloped neighborhoods often remain permanently shaded, rendering them uninhabitable and contributing to urban inequities [19]. Addressing these challenges requires a nuanced understanding of how topography interacts with building design, as well as the integration of slope-sensitive guidelines into urban regulations. By incorporating topographical considerations into daylight analysis, cities like Amman can create more equitable and livable urban environments.

2.5. Challenges in Sloped Urban Areas

2.5.1. Topographical Constraints

Steep slopes present significant challenges for urban planning, particularly in balancing density with daylight access. In cities like Amman, where elevation differences can exceed 900 m, the natural terrain complicates the design of residential buildings, often leading to overcrowding and poor daylight conditions. Economic pressures further exacerbate these issues, as developers prioritize maximizing plot usage over environmental and social considerations. For instance, in sloped areas, buildings are often constructed closer together to reduce land acquisition costs, resulting in longer shadows and reduced daylight penetration [2]. This overdevelopment not only compromises the livability of residential spaces but also strains infrastructure, as steep gradients increase construction costs and maintenance challenges. Addressing these topographical constraints requires innovative planning strategies that reconcile economic demands with the need for equitable daylight access, ensuring that urban growth does not come at the expense of residents’ well-being.

2.5.2. Basement Usage

Basements are a common feature in Amman’s residential buildings, particularly in sloped areas where they are used to maximize usable space. However, these spaces often suffer from poor daylight conditions due to their below-ground location and the presence of retaining walls, which block natural light from entering [19]. Studies have shown that shaded basements are prone to dampness, poor ventilation, and inadequate lighting, creating unhealthy living conditions that can lead to respiratory issues and psychological distress [6]. Despite these risks, basements are frequently used as living spaces, especially in low-income neighborhoods where housing shortages and affordability issues force residents to occupy substandard accommodations. This highlights the urgent need for regulatory reforms that restrict basement habitation and promote daylight-friendly design practices, ensuring that all residents have access to safe and habitable living environments.

2.5.3. Street Orientation and Width

Street orientation and width play a critical role in determining daylight access in dense urban neighborhoods. In Amman, narrow streets and poor orientation often exacerbate shading, as buildings cast long shadows that block sunlight from reaching adjacent properties [1]. For example, streets running east to west tend to receive more sunlight than those oriented north to south, but this advantage is often negated by the high density of buildings and inadequate setbacks. Furthermore, narrow streets in sloped areas amplify shading effects, as the combination of steep gradients and tall buildings creates deep, persistent shadows. Addressing these issues requires a holistic approach to urban design, including wider streets, optimized building orientation, and slope-sensitive setbacks that minimize shading while maintaining connectivity and accessibility. By prioritizing daylight access in street planning, cities like Amman can create healthier, more livable urban environments.

2.6. Gaps in Existing Research

2.6.1. Lack of Slope-Sensitive Studies

Despite the growing body of research on daylight access in urban environments, there is a notable scarcity of studies focusing on sloped cities, particularly in the Middle East. While cities like San Francisco and Hong Kong have developed slope-sensitive regulations to address shading issues, research in regions with similar topographies, such as Amman, remains limited [15,16]. This gap is particularly concerning given the unique challenges posed by Amman’s semi-arid climate and rugged terrain, where steep slopes and high-density development exacerbate shading effects. Existing studies often prioritize flat urban areas or focus on thermal comfort and energy efficiency, overlooking the interplay between topography and daylight access [18]. Addressing this gap requires context-specific research that accounts for Amman’s unique geo-climatic conditions, providing actionable insights for urban planners and policymakers. By filling this void, future studies can contribute to the development of adaptive regulations that balance urban growth with daylight equity in sloped cities.

2.6.2. Policy-Relevant Research

While simulation tools like Revit and ClimateStudio have advanced our understanding of daylight and shadow dynamics, there is a lack of research that translates these findings into actionable urban policies. Many studies focus on theoretical models or case-specific analyses without proposing scalable solutions that can be integrated into building codes and zoning regulations [10]. For example, despite the widespread use of solar analysis tools in academic research, their application in policymaking remains underexplored, particularly in cities like Amman where outdated regulations fail to address modern urban challenges. Bridging this gap requires interdisciplinary collaboration between researchers, policymakers, and urban planners to ensure that simulation-based insights inform guidelines so that they are practical and enforceable. By prioritizing policy-relevant research, scholars can play a pivotal role in shaping urban environments that prioritize daylight access, health, and sustainability, setting a precedent for cities worldwide.

3. Methodology

3.1. Study Area

This study focuses on the Al Jubayhah district in Amman, Jordan, a densely populated residential area characterized by steep slopes (0–30%) and mid-rise buildings (4–8 stories). This district was selected due to its diverse topography, which amplifies shading effects, and it is designated as Residential Zone B under Amman’s Building Code No. 67, 1979. With approximately 250 buildings and a population of 9089, Al Jubayhah (Figure 1) provides a representative case study for examining the interplay between urban regulations, topography (Figure 2), and daylight access in sloped cities.

3.2. Data Collection

Data collection involved field surveys conducted between January and March 2023, during which building heights, setbacks, and street widths were measured using laser distance meters and GPS devices. Slope gradients were calculated using surveying tools and GIS data, with plots categorized into four groups: flat (0–15%), moderate (15–20%), steep (20–30%), and very steep (>30%). Additionally, basement usage and daylight conditions were documented through visual inspections and interviews with residents.

3.3. Simulation Tools and Parameters

Shadow patterns were analyzed using Revit 2023 and AutoCAD 2022, which allowed precise 3D modeling of building masses and solar geometry. Simulations were conducted for three critical dates—March 21 (spring equinox), September 21 (autumn equinox), and December 21 (winter solstice)—at three times each day (8:00 am, 12:00 pm, 4:00 pm) to capture seasonal variations. The simulations accounted for slope gradients and retaining walls, which significantly impact shadow lengths and basement illumination.

3.3.1. Slope Calculation

To account for the impact of terrain variations on building heights and shadow lengths, the slope percentage was calculated using the following formula:

Slope (%) = (Rise/Run) × 100

Here, ‘Rise’ represents the vertical elevation difference between two points, and ‘Run’ is the horizontal distance between them. These values were obtained from topographic maps of Amman. The calculated slope percentages were then used to adjust building heights in the 3D model, ensuring accurate simulation of shadow lengths and daylight access across different terrains.

3.3.2. Daylight Factor (DF)

Daylight penetration in residential units was evaluated using the daylight factor (DF), calculated as

DF (%) = (Indoor Illuminance (lux)/Outdoor Illuminance (lux)) × 100

Indoor illuminance values were derived from simulations in Revit, while outdoor illuminance was based on overcast sky conditions. A DF of 2% or higher is considered adequate for residential spaces, as per international standards.

3.3.3. Spatial Daylight Autonomy (sDA)

The spatial daylight autonomy (sDA) metric was used to assess the annual daylight performance of residential units. It is defined as

sDA = (Area receiving ≥ 300 lux for ≥ 50% of occupied hours/Total area) × 100

3.4. Analysis Techniques

Shading was quantified by calculating the percentage of shaded areas for each building and plot, with results categorized by slope and season. Basement daylight conditions were assessed using the daylight factor (DF), a metric that measures the ratio of indoor to outdoor illuminance. Spatial daylight autonomy (sDA) was also calculated to evaluate the percentage of floor area receiving sufficient daylight throughout the year.

Validation and Limitations

Simulation results were validated by comparing shadow patterns with field observations and existing studies on Amman’s urban environment. While the simulations provided robust insights, limitations included the reliance on 2D maps for some topographical data and assumptions about building materials (e.g., uniform reflectivity). These limitations were mitigated by cross-referencing multiple data sources and conducting sensitivity analyses (see Figure 3).

4. Decision

4.1. Preliminary Site Visit

An initial site visit was conducted to gather essential data, including the number of above-ground floors for each building within the study area. This systematic documentation provided a foundational dataset for further analysis.

The selected site spans approximately 8.75 square kilometers, housing a population of 9089 across 250 residential buildings. Due to its diverse topography, many plots are positioned between two streets, leading to variations in floor levels. The study area falls under Residential Zone B, as per Amman’s Building and Planning Regulations No. 67 (1979) (Figure 4). Additionally, the presence of undeveloped land (Figure 5) suggests potential for future urban expansion.

Observational data gathered from the site provided an overview of the area, supplemented by images for reference (see Figure 6). Most residents within the area were homeowners, with only a small portion being renters. Furthermore, it was observed that the predominant housing type in the vicinity was apartments, indicating a common residential pattern characterized by multi-family dwellings.

4.2. Basement Assessment

This study paid special attention to underground structures, particularly basements, which were evaluated in terms of their structural characteristics and daylight access. A detailed survey was conducted to document the number of underground floors per building (Figure 7 and Figure 8). The results were later incorporated into 3D digital models in Revit software for further analysis.

The permanent shading over 39.6% of basements in Al Jubayhah has significant implications for quality of life, particularly in low-income households. The lack of daylight in these spaces leads to poor ventilation, dampness, and mold growth, creating unhealthy living conditions. Furthermore, the absence of natural light has been linked to psychological distress, including feelings of isolation and depression. This issue highlights the inequitable distribution of daylight access in Al Jubayhah, where Residential Zone B, C, or D neighborhoods are disproportionately affected by poor urban design policies. To address these challenges, we recommend revising urban planning policies to incorporate slope-adjusted setbacks and daylight optimization strategies, ensuring equitable access to natural light for all residents.

4.3. Street Width Measurement

Street widths were systematically recorded to assess their impact on shadow patterns. Narrow streets (≤12 m) were of particular concern, as they exacerbate shading effects from adjacent buildings (Figure 9).

4.4. Topography and Slope Calculation

Using surveying tools and GIS data, slope gradients were categorized into four groups:

• Flat terrain (0%);
• Moderate slope (15%);
• Steep slope (20%);
• Very steep slope (30%).

This classification enabled a better understanding of how terrain inclination influences shadow lengths, daylight availability, and basement conditions (Figure 10).

4.5. Data Integration into Revit

All collected data—building heights, setbacks, street widths, slope gradients, and basement conditions—were entered into Revit software to develop accurate 3D digital models. These models served as the foundation for the shadow analysis and daylight simulations, which examined how building layouts and topography impact daylight access throughout the year.

4.6. Digital Modeling

Following the digital modeling process using Revit software, this study focused on analyzing the effect of shadows cast by surrounding buildings on the south elevation of each building. Measurements were taken on the ground floor and above, as basements are also influenced by retaining walls built on the edge of the lot, which reduce the distance between the building and the wall. Consequently, if an effect is observed on the ground floor, the impact on the basement is expected to be more significant. Observations were conducted on 21 March, 21 September, and 21 December at three times each day: 8:00 am, 12:00 pm, and 4:00 pm. Figure 11 illustrates the distribution of shadow effects from surrounding buildings, revealing that the variation in building distribution does not necessarily imply that plots with steeper slopes are more affected by shadows from adjacent structures. Additionally, the slope of each plot was measured to further contextualize the findings.

4.7. Shadow Analysis

Buildings oriented with one of their faces directly south experience significant shading. Notably, buildings situated in both the southern and northern parts of the study area are affected. For example, Building 113, with its south elevation heavily shaded, consists of four floors above ground and five basements below ground, making it particularly problematic. Similarly, Building 114, adjacent to Building 113, has three basements and is also significantly shaded. However, Figure 12 (left), suggests no shading effect for Building 114, which arises because the shading analysis focused on the floors above ground level, considering the dimensions of surrounding shadows and building setbacks, while excluding the shadow cast by the retaining wall.

Building 106, with four basements and a south-facing retaining wall, does not receive daylight in its basements (see Figure 12, right). This condition is shared by Buildings 126 and 127, with Building 126 being more shaded throughout the year (see Figure 12, bottom). According to Appendix A, nearly the entire study area is shaded in December, with approximately 78.3% covered. In March, the average shading percentage is around 38.3%, while in September, it is approximately 43.0%. Additionally, 23.5% of the buildings are shaded throughout the entire year.

The street width, indicated in green if it is 12 m or less, plays a significant role in shadow patterns. However, even buildings facing wide streets are not necessarily unaffected by shadows. For instance, five buildings (numbers 2, 3, 13, 16, and 28) face wide streets but still experience shadow effects due to the orientation of the street. In contrast, all buildings facing three streets around a lot are unaffected by shadows, except for Building 85, as all these streets are narrower than 12 m, as shown in Figure 13.

When the slope was calculated using the formula X/Y = slope, where X represents the height of the lot, this indicator was used for comparison with the number of basements in each building. If the number of basements exceeds the lot’s height, all basements in the building will be shaded from daylight, regardless of the surrounding buildings. The retaining wall will also cast a shadow. Figure 14 illustrates buildings where the number of basements exceeds the height X (measured in meters). The percentage of buildings with this basement shading issue in the research area is 39.6%.

The final observation reveals that several buildings have their basement’s south elevation facing a retaining wall. Consequently, these basements experience constant shading and lack adequate daylight, as shown in Figure 14. While some basements remain unaffected by shadows from surrounding buildings, the retaining wall’s shadow significantly impacts them due to the close proximity between the wall and the building.

To assess the impact of the existing setback code on daylight exposure, simulations were conducted for each zone under ideal conditions. These simulations considered scenarios without basements and with building heights limited to 15 m and assumed that there were no irregularities in any part of the code. The analysis focused on the rear setback, as it represents the longest distance between two buildings. The results of these simulations are detailed in

Table 2. The shadow domains for all residential zones. All values are in meters. See also Appendix B.

	Day (Time)
	21 March			21 September			21 December
	8:00 am	12:00 pm	4:00 pm	8:00 am	12:00 pm	4:00 pm	8:00 am	12:00 pm	4:00 pm
Residential Zone A	Max distance = 7 m (rear setback) × for 2 lots = 14
Flat slope	7.54	7.52	7.61	7.05	7.44	7.74	29.4	17.53	63.96
15% slope	9.99	9.80	10.00	9.39	9.44	9.22	31.12	25.83	68.58
20% slope	10.82	10.64	10.74	10.17	10.29	12.74	51.50	29.91	69.62
30% slope	12.68	12.39	12.72	11.82	11.92	11.71	62.5	36.97	92.65
Residential Zone B	Max distance = 6 m (rear setback) × for 2 lots = 12
Flat slope	7.86	7.68	7.76	6.36	7.48	7.28	29.41	17.35	63.81
15% slope	10.02	9.96	10.12	9.55	9.70	9.36	46.23	26.30	78.92
20% slope	12.00	10.07	12.95	9.66	9.78	9.47	48.95	28.34	80.32
30% slope	15.78	12.03	15.87	14.93	11.46	14.81	60.68	35.65	90.60
Residential Zone C	Max distance = 4 m (rear setback) × for 2 lots = 8
Flat slope	7.61	7.58	8.00	7.23	7.23	7.20	29.36	17.43	63.92
15% slope	10.41	8.91	8.36	9.87	8.60	9.76	39.85	23.46	70.56
20% slope	11.57	9.71	11.56	10.96	9.32	10.74	44.33	26.10	74.92
30% slope	13.78	11.28	13.87	13.15	10.90	12.94	53.11	31.32	83.51
Residential Zone D	Max distance = 2.5 m (rear setback) × for 2 lots = 5
Flat slope	7.92	7.71	7.48	7.26	7.43	7.20	29.61	17.38	64.43
15% slope	12.00	10.15	12.26	9.02	9.24	6.82	36.45	22.04	76.75
20% slope	7.66	11.08	12.26	7.86	10.26	11.12	31.03	16.92	68.2
30% slope	13.78	14.06	6.82	6.61	9.26	9.07	64.82	17.45	70.75

Over max distance .

.

This table was generated using Revit software, analyzing different slope conditions: flat plots, 15% slope, 20% slope, and 30% slope. The distance covered by shadows was then measured using AutoCAD software. For Residential Zone A, the rear setback is 7 m; if the rear setback of an adjacent building is combined, the total distance exceeds 14 m. If the shadow length exceeds 14 m, it blocks daylight from reaching the adjacent building mass. Similar analyses were conducted for all other zones, ensuring a comprehensive evaluation of shadow impacts under varying slope conditions.

Uniform setbacks, typically ranging from 4 to 7 m, are designed for flat terrain and fail to account for the complexities of sloped landscapes. Our simulations reveal that slopes significantly increase shadow lengths, with a 15% slope extending shadows by approximately 50% compared to flat terrain. On steeper slopes (e.g., 30%), shadows can extend up to 25 m, severely limiting daylight penetration into adjacent residential units. For instance, a unit on flat terrain achieved a daylight factor of 2.5%, whereas the same unit on a 20% slope achieved only 1.5%, falling below recommended standards. These findings underscore the need for slope-adjusted setbacks, which our data shows can reduce shadow lengths by up to 30% on steep slopes, thereby improving daylight access and enhancing occupant comfort. Urban planning policies should prioritize such adaptive strategies to address the unique challenges of sloped terrains.

The findings of this study align with previous research in Jordan, such as [1], which highlighted the importance of solar radiation in urban planning, and [22], which emphasized the challenges of daylighting in high-density urban environments. However, while these studies focused on flat terrains, this study addresses the unique challenges of mountainous cities like Amman, where slope variations significantly impact daylight access. For instance, ref. [23] explored the effects of urban geometry on microclimates, but their work did not account for the role of topography in exacerbating shading effects. By proposing slope-adjusted setbacks, this study fills a critical gap in the literature and provides actionable solutions for improving daylight access in sloped urban areas. Ref. [18], who focused on Nablus, provided insights into thermal comfort and energy efficiency in Mediterranean cities, which are applicable to Amman. It emphasizes the importance of natural light in enhancing building performance and emphasizes the role of building orientation and materials in reducing cooling loads. However, this study goes further by addressing the social equity implications of daylight deprivation, particularly in low-income neighborhoods where basements and lower floors are often permanently shaded. Furthermore, the Greater Amman [19] current regulations, which enforce uniform setbacks, are shown to be inadequate for addressing shading in sloped neighborhoods. This study’s recommendations for adaptive guidelines offer a more context-sensitive approach to urban planning, balancing developmental density with daylight equity.

5. Conclusions

Amman, a mountainous city characterized by steep slopes, applies uniform regulations to all land regardless of topography. With the city’s population growing rapidly, the demand for housing has surged, leading to extensive urban sprawl. Economic considerations often dominate investment decisions, resulting in various challenges. In real estate development, it is crucial to evaluate how new buildings will impact their surroundings. While it is impossible to completely halt urban sprawl, its effects can be mitigated through thoughtful planning and regulation.

This research evaluates building setbacks in Amman as mandated by municipal legislation (No. 67, 1979), with a focus on daylight access for residential properties (see

Table 3. The setbacks before and after modification.

Residential Zone	Front Setback		Side Setback		Rear Setback		Max Height
	Before	After	Before	After	Before	After	Before	After
A	5	5	5	5	7	6	15	16
B	4	4	4	4	6	5
C	4	4	3	3	4	3
D	3	3	2.5	2.5	2.5	3

). The key findings include the following:

• Residential Zone A: When buildings are arranged back to back facing south, the distance between them generally allows daylight to enter, except during winter when shadows cover the lower building. However, when buildings are arranged side by side facing south, daylight access is often obstructed throughout the year, as the distance between blocks is only 10 m—less than in the back-to-back arrangement.
• Residential Zones B, C, and D: In back-to-back arrangements facing south, daylight is frequently blocked for much of the year. The situation worsens in side-by-side arrangements, where daylight access is significantly reduced.

Although the 2017 Modified Building and Planning Regulations for Amman (No. 67, 2017) introduced some changes, it still fails to adequately address the issue of daylight access. This highlights the need for more comprehensive regulations that consider topography, building orientation, and the impact of shadows to ensure adequate daylight for all residential areas.

The recent modifications to building regulations, which reduced the rear setback by two meters and increased the maximum building height by one meter, have further exacerbated the issue of daylight access. These changes decrease the distance between back-to-back buildings and increase shadow coverage, negatively impacting the availability of natural light in residential areas.

The second key conclusion from the analysis pertains to basement conditions (see Figure 15). Many buildings have a number of basements that exceed the height of the slope, resulting in these basements being entirely underground and deprived of natural light. Furthermore, the orientation of retaining walls for basements plays a critical role in daylight access. Retaining walls should ideally face north to allow daylight to enter from the south, which is the optimal direction for maximizing natural light.

As illustrated in Figure 15, the slope is 20%. The building on the right exceeds the height of the slope by three basements, necessitating the construction of a retaining wall. Unfortunately, this retaining wall is oriented towards the south, blocking daylight to all three basements and leaving them shaded throughout the year. Similarly, the ground floor of the building on the left was excavated to create a basement, resulting in a space that is entirely below ground level. This design severely compromises daylight access, as shown in Figure 16, and highlights the detrimental impact of such construction practices on natural light availability.

Furthermore, the impact of shading from buildings was not adequately considered for zones in sloped areas, despite shadows being directly influenced by the steepness of slopes. The distribution of lots in the district does not align with topographical lines, and there are no specific regulations addressing sloped lots.

Streets located at lower elevations and facing south experience less shadow impact compared to those facing north. On north-facing streets, shadows cast by retaining walls significantly affect the northern side of buildings, as illustrated in Figure 17. This discrepancy highlights the need for zoning regulations that account for topography and shadow patterns to ensure equitable daylight access across all areas.

We also highlight the psychological impact of shaded areas, particularly living rooms, which are central to social interactions and activities such as reading. The mood and well-being of occupants are significantly affected when living rooms remain shaded throughout the day, as these spaces are where much of their time is spent. Many shaded living rooms are located on basement floors, reflecting the prevalence of residential apartments in Amman.

Additionally, the orientation of living room windows often fails to ensure adequate daylight exposure, leading to an over-reliance on artificial lighting. This underscores the insufficient access to natural light in many residential spaces. As a result, occupants tend to spend more time using mobile phones or watching television, which can contribute to discomfort and a lack of engagement with their surroundings. Daylight is essential not only for enhancing bodily activity but also for promoting overall well-being and quality of life.

6. Recommendations

Our findings reveal that Amman’s current regulatory framework, particularly Building Code No. 67, 1979, fails to account for slope variations, leading to inequitable daylight access and poor living conditions in lower-income neighborhoods. To address these issues, we propose the following adaptive guidelines:

6.1. Dynamic Setbacks Tied to Slope Percentages

To account for slope variations, we recommend implementing dynamic setbacks that increase with slope steepness. For instance, setbacks could range from 15 m on flat terrain to 26.4 m on 30% slopes, ensuring adequate daylight penetration across all terrains. This approach would mitigate the excessive shading caused by uniform setbacks in sloped areas.

6.2. Restrictions on Basement Habitation

Given the prevalence of permanently shaded basements in sloped areas, we recommend restricting basement habitation in zones with slopes exceeding 20%. Where basements are necessary, design improvements such as light wells and ventilation systems should be mandated to improve livability and prevent health issues associated with poor ventilation and dampness.

6.3. Optimized Street Orientation

Street orientation should be optimized to align with the sun’s path, particularly in north–south directions, to maximize daylight access. This approach can reduce shadow lengths and improve daylight penetration in residential units, particularly in densely built neighborhoods.

Table 4. The proposed guidelines.

Guideline	Description	Implementation
Dynamic Setbacks	Setbacks increase with slope steepness to ensure adequate daylight penetration.	15 m for flat terrain, 20 m for 15% slopes, 26.4 m for 30% slopes.
Restrictions on Basement Habitation	Limit basement habitation in areas with slopes >20% to prevent poor living conditions.	Mandate light wells and ventilation systems where basements are necessary.
Optimized Street Orientation	Align streets with the sun’s path to maximize daylight access.	Prioritize a north–south orientation in new developments.

These adaptive guidelines not only address the shortcomings of Amman’s current regulatory framework but also promote equitable daylight access, healthier living conditions, and sustainable urban development.

below summarizes the proposed guidelines for clarity:

The footprint of basement floors should extend 1.5 m beyond the rear setback, totaling 4.5 m (see Figure 18).

6.4. Increase Side Setbacks for Land at Higher Elevations

For land situated at higher elevations, the side setback should be increased from 4 m to 7 m to minimize the impact of shadows cast by surrounding buildings (see Figure 19).

6.5. Adjust Rear Setbacks Based on Building Height and Solar Access

The recommended rear setback varies according to each building’s height, with the angle of solar access determined using the Revit program (as outlined in

Table 5. The proposed rear setback.

Flat slope
Height of building	Distance (rear setback)	Diagram
3 m	2.8 m
6 m	5.2 m
9 m	8.3 m
12 m	11.7 m
15 m	13.8 m
20% slope
3 m	11.0 m
6 m	12.9 m
9 m	16.6 m
12 m	19.3 m
15 m	22.1 m
30% slope
3 m	15.3 m
6 m	17.3 m
9 m	20.8 m
12 m	23.6 m
15 m	26.4 m

). This approach ensures optimal sunlight exposure for the building’s design and orientation.