Enhancing Urban Walkability in Hot Climates: Strategies and Solutions

Introduction

In modern urban environments, comfort is a key consideration for mobility. Nearly all automobiles and public transit vehicles are equipped with air conditioning, providing a reprieve from hot weather. Additionally, in cities with extreme climates, shaded parking lots are a common sight. However, when it comes to pedestrians, similar considerations for comfort are often overlooked. This article delves into the necessity of improving pedestrian comfort in hot climate cities and explores various strategies to achieve this goal.

Walking remains a prevalent mode of transportation, accounting for 12-25% of total trips. Despite its importance, walking infrastructure receives minimal support from most communities, which allocate less than 2% of their total transportation infrastructure expenditures to pedestrian facilities (Litman 2023b). This underinvestment leads to uncomfortable and unsafe walking conditions, particularly affecting vulnerable groups such as children, seniors, and individuals with disabilities. As a result, many travelers are compelled to drive instead of walking or using public transit, even for short trips that could be made more accessible with better infrastructure (AlKheder 2023).

Walkability Planning

To enhance pedestrian access, cities need to implement effective walkability planning. Walkability is often measured by the "walkshed," which refers to the area that can be reached on foot within a reasonable time frame. This typically ranges from 5-15 minutes (0.3 to 1.5 kilometers) for running errands and 10-30 minutes (0.6 to 2.0 kilometers) for commuting (Steuteville 2017).

Pedestrian facilities must be well-designed and strategically implemented to maximize their benefits (Santos 2015). Various metrics, including pedestrian level-of-service, walkability indices, and Universal Design Standards, help assess walking conditions. In addition, climate factors such as extreme heat, cold, wind, and rain significantly impact walkability, making proper planning crucial for pedestrian comfort.

Hot-Climate Walking Comfort

Outdoor physical activity, including walking, becomes uncomfortable and potentially hazardous when temperatures rise. According to the National Weather Service of USA, walking in hot climates becomes unhealthy when dry-bulb temperatures exceed 38°C, wet-bulb temperatures exceed 32°C, or the heat index exceeds 55°C. Wet-bulb temperatures above 35°C are considered deadly.

A recent study, Quantifying the Human Cost of Global Warming, estimates that the number of people suffering from extreme heat will increase from approximately 600 million today to two billion by 2030 (Lenton et al., 2023). Walking on hot, unshaded pathways exacerbates discomfort, as pedestrians absorb radiant heat from sunlight reflected off light-colored surfaces and from dark surfaces that radiate heat. This issue is particularly prevalent in cities, where the urban heat island effect raises ambient temperatures by 1-7°C due to factors like dark pavement, reduced green spaces, and motor vehicle operations (USEPA 2023).

The discomfort caused by extreme heat discourages walking, leading to reduced physical activity and increased driving. This creates a self-reinforcing cycle of more emissions, more pavement, more urban heat, and less pedestrian comfort (AlKheder 2023; Basu et al., 2024; Silva & Akleh 2018).

Strategies for Reducing Urban Heat Exposure

Fortunately, there are several ways to mitigate urban heat exposure and improve pedestrian comfort. These strategies include designing buildings with natural and mechanical cooling systems, increasing green spaces and tree cover, and providing shaded walkways (Atef 2013; Chaudhry 2011; Ladd & Meerow 2022; Litman 2022; Rahman 2019). Pedestrians and cyclists can benefit from "shadeways" (shaded sidewalks and bikeways) and "pedways" (enclosed, climate-controlled walkways). To be truly effective, these solutions must be part of an integrated network that provides convenient and comfortable pedestrian connections between homes, services, and public transit within compact urban areas.

While trees can offer natural shade, they require adequate space, water, and maintenance, and can take many years to mature. In many cases, trees alone do not provide sufficient shade coverage (more than 80% of the sidewalk), necessitating the use of additional structures like metal, wood, bamboo, or fabric awnings. These shadeways and shade canopies can also protect pedestrians from rain and snow. In addition, bike paths can be designed with shadeways to provide continuous protection for cyclists (Litman, 2024),

The Cool Walkshed Index

The Cool Walkshed Index (CWI) (Litman, 2024) is a valuable tool for evaluating pedestrian thermal comfort in hot climate cities. It assesses the quality of walkways, buildings, and neighborhoods, helping urban planners identify where shadeways and pedways are needed. CWI maps can guide the placement of shaded and climate-controlled pedestrian pathways and set improvement targets.

Currently, most buildings and neighborhoods fall into CWI ratings of D or E, indicating either incomplete or unshaded walkways that provide inadequate access to local services and public transit. Only a few cities have developed pedway networks that achieve higher CWI ratings, such as B or A.

Cool Walkshed Index (CWI) Ratings:

• A: Connected to a continuous, enclosed, climate-controlled pedway that provides access to commonly-used services (e.g., shops, restaurants, cultural activities) and high-quality public transit stations.
• B: Located within 300 meters of a pedway entrance in areas where temperatures frequently exceed 38°C, or within 100 meters in areas where temperatures exceed 43°C.
• C: Connected to a continuous shadeway that offers at least 80% shade coverage during midday and provides access to services and transit, with shaded transit waiting areas.
• D: Connected to a continuous but unshaded walkway that provides access to commonly-used services and public transit.
• E: Connected to an incomplete walkway with inadequate access to services and transit.
• F: Contains major barriers to walking and accessing local services and transit.

CWI ratings can help individuals make better location decisions, encouraging them to choose homes in areas with higher ratings. Improved walking conditions can increase exercise and enjoyment while reducing vehicle expenses. Developers and property owners can also use CWI ratings to justify investments in shadeways and pedways to enhance neighborhood livability.

Of course, these facilities must be carefully designed and managed to accommodate all types of users, including those with disabilities, families with children, and travelers with luggage (NTA 2021). Proper shadow analysis should be conducted to ensure that sidewalks and paths have at least 80% shade during summer mid-days (Rodriguez 2020). Furthermore, shadeways and pedways should be well-maintained to ensure safety, comfort, and attractiveness.

Pedway Network Examples

Many cities have developed pedway networks, with variations such as underground cities and elevated skyways. However, these networks are often limited in scale and only serve a portion of pedestrian destinations (Cui 2021).

Benefits of Shadeways and Pedways

To maximize the benefits of shadeways and pedways, they should be developed within compact, mixed-use urban villages where many homes and workplaces are within walking distance of commonly-used services. High-quality public transit, ride-hailing, and car-sharing services can reduce the need for private car ownership. Parking should be unbundled from housing costs, ensuring residents only pay for the parking they need. Transportation demand management (TDM) incentives can further encourage a reduction in vehicle ownership and use, thereby maximizing the economic and environmental benefits of shadeways and pedways (Litman, 2024).

Costs of Shadeways and Pedways

While shadeways and pedways are more expensive to construct than basic sidewalks, they offer long-term benefits that justify the investment. A typical sidewalk costs between $50 and $150 per linear foot, depending on materials and conditions (Litman 2023a). Adding a durable canopy can double those costs, while enclosed pedways are even more expensive, especially when tunnels, escalators, or elevators are required. Additionally, these structures can increase operational, administrative, and liability costs. However, when compared to the costs of urban roadways, parking facilities, and motor vehicle expenses, shadeways and pedways offer a cost-effective alternative for enhancing urban mobility (Litman, 2024).

Conclusion

As cities around the world continue to grow and confront the challenges of climate change, improving walkability—especially in hot climates—will become increasingly important. By investing in shadeways and pedways, urban areas can provide safe, comfortable, and efficient alternatives to driving, benefiting both pedestrians and the environment. These investments have the potential to create healthier, more livable cities for everyone.

References

AlKheder, S. (2023). The relation between walkability in hot arid regions and the built environment: The case of Kuwait in the Arabian Gulf. Journal of Urbanism. https://doi.org/10.1080/17549175.2023.2254742

Atef, M. (2013). Encouraging walkability in GCC cities: Smart urban solutions. Smart and Sustainable Built Environment. https://doi.org/10.1108/SASBE-03-2013-0015

Basu, R., et al. (2024). Hot and bothered: Exploring the effect of heat on pedestrian behavior and accessibility. TRB Annual Meeting. https://re.public.polimi.it/handle/11311/1258853

Chaudhry, A. G. (2011). Dubai pedways development strategy: An enabling framework for better accessibility to public transport. International Association of Public Transport. https://trid.trb.org/view/1101430

Lenton, T. M., et al. (2023). Quantifying the human cost of global warming. Nature Sustainability. https://doi.org/10.1038/s41893-023-01132-6

Litman, T. (2023). Cool walkability planning: Providing pedestrian thermal comfort in hot climate cities. Victoria Transport Policy Institute. https://vtpi.org/cwp-JCEES_2023.pdf

Litman, T. (2023). Evaluating active transport benefits and costs. Victoria Transport Policy Institute. https://www.vtpi.org/nmt-tdm.pdf

Litman, T. (2023). Fair share transportation planning. Victoria Transport Policy Institute. https://www.vtpi.org/fstp.pdf

Litman, T. (2024). Cool walkability planning. Victoria Transport Policy Institute. Retrieved from https://vtpi.org/cwp-JCEES_2023.pdf

National Weather Service. (n.d.). Definitions of dry-bulb and wet-bulb temperatures. National Oceanic and Atmospheric Administration. https://www.weather.gov/source/zhu/ZHU_Training_Page/definitions/dry_wet_bulb_definition/dry_wet_bulb.html

Rahman, A. (2019). The feasibility of walkability in extreme heat. Cities from Salt. https://www.citiesfromsalt.com/blog/the-feasibility-of-walkability-in-extreme-heat

Rodriguez, E. (2020). Shadow analysis: Tools and software. LinkedIn. https://www.dhirubhai.net/pulse/shadow-analysis-tools-software-eduardo-rodriguez-e-i-t-

Silva, J. P., & Akleh, A. Z. (2018). Investigating the relationships between the built environment, the climate, walkability, and physical activity in the Arabian Peninsula: The case of Bahrain. Cogent Social Sciences, 4(1). https://doi.org/10.1080/23311886.2018.1502907

USEPA. (2023). Learn about heat islands. U.S. Environmental Protection Agency. https://www.epa.gov/heatislands/learn-about-heat-islands