Street Notes 2: Solutions in Action at Culdesac Tempe

by Sonam Velani, Lyn Stoler, and Anson Yu

What if we un-paved paradise?

Major thanks to Nicole Kelner for coaching Lyn on her drawings every week! We’re slowly but surely seeing improvements!

How would you build a neighborhood from the ground up? 

What if you had to make it withstand some of the hottest temperatures in America and annual monsoons? And what if we told you to put it near America's fastest growing major city? 

Odds are, if you spent enough time designing your answer, you might end up with something that looks like Culdesac in Tempe, Arizona. 

In August, we visited Culdesac Tempe – America's first purpose-built car free neighborhood full of housing, shared bikes, and much else. For those who aren't familiar with Culdesac, it will be home to a neighborhood of about 1,000 car-free residents, in addition to restaurants, a grocery store, and outdoor spaces for the public at large. 

Culdesac didn’t set out to build an urban lab of climate solutions. So it seems ironic that their site is one of the densest aggregations of climate solutions we've seen in one place.

This is driven by Culdesac's location on the frontlines of climate change. Tempe suffers from extreme heat and a gnarly monsoon season every year. During Lyn's week-long visit in August, daytime temperatures rarely dropped below 112 degrees Fahrenheit. And during monsoon season, Anson had to bike home with her eyes closed through a pre-thunderstorm dust haboob. 

Culdesac’s focus on beauty and livability in such an extreme environment has led the team to a design that even climate-first developers would be hard-pressed to beat. While some of this is enabled by technology, a lot of it boils down to successful implementation through private-public partnerships with the City of Tempe, local community groups like the Tempe Bicycle Action Group, and public transit agencies like Valley Metro Rail. 

Culdesac has worked with the City of Tempe government and community to take on parking minimums, invest in transit, and even change zoning rules to build taller, faster, and more affordably. Tempe's small but mighty city government is focused on innovation, investment, and implementation. In the process, they're building real solutions for climate change, the housing crisis, and the Phoenix area's famous sprawl. 

So today, we're going to tell you about all the solutions we saw in action at Culdesac.

Solutions! 

Yes, we know this shade structure looks like a slice of bacon. It's the best that Lyn could do after several attempts, but you can find a real picture of the shading structure below. 

Shading is one of the most effective ways that we can reduce the impact of the urban heat island effect. In fact, when we took temperature readings, we often found that the ground underneath shade structures was up to 40 degrees Fahrenheit cooler than that in direct sun — yeah, we had to do a double take on our thermometers! Culdesac is cashing in on the cool factor through building overhangs, tree canopies, and shade structures across the development. 

• Building layout: The three-story building height, layout, and proximity of units provide shade along pedestrian routes throughout the day.

• Shade structures: The site is sprinkled with structures that double as art. Their rust color also has a higher solar reflectance than typical metal, preventing heat from being absorbed into the structures. 

By reducing parking spaces, the Culdesac site provides 50% more room for landscaping, which means more greenery and cooling instead of cars and asphalt. Even in Tempe's desert environment, the right trees can create huge adaptation benefits for temperature, air quality, and stormwater absorption.

• Vines: Climbing plants like bougainvillea are seeded to cover whole walls, contributing to cooling a and energy savings — and more importantly, aesthetics 🙂

• Trees: Culdesac is making use of native trees like the Palo Verde — Arizona's Swiss Army Knife of weather adaptation. It requires shockingly little water to maintain (it costs less to water a Palo Verde tree for a year than it does to buy a pack of gum!), and its broad leafy branches provide ample shade while its stormwater absorption ability protects against erosion from heavy monsoon rain.

When it comes to climate resilience, the structure of a neighborhood and its individual buildings is just as important as the materials that it's made of. 

• Courtyards: Each cluster of units is centered on a courtyard, known to be microclimate modifiers that improve comfort levels for all residents.

• Hallways: Single-loaded corridors are hallways that only have units on one side, rather than on both sides. It may not seem like a big deal, but Culdesac's use of single loaded corridors ensures that each unit can get a cross-breeze and natural light, which reduces both heating and cooling costs!  

As a quick explainer, a single-loaded corridor just means that it only has units on one side of the hallway, while a double-loaded corridor has units on both sides of the hallway. 

• Wind flow: Wind is one of the main determinants of urban temperature, which means that engineering our environments to encourage wind flow can help lower temperatures! At Culdesac, buildings are oriented such that the shorter axis generally aligns with winds to encourage wind-enabled cooling. 

• Manufactured serendipity: Smaller, personal roads spill into the larger walkways and shared spaces to induce social interactions and a sense of community. This is, surprisingly, an incredibly valuable element for extreme heat resilience! During extreme heat events, checking on elderly or vulnerable neighbors is often one of the most effective ways to protect people's health (this is the thesis behind New York City's Be a Buddy program). A socially connected neighborhood builds that community and climate resilience naturally! 

We mentioned this briefly above, but colors matter a lot when it comes to extreme heat. Materials of different colors have different solar reflectance — which measures how much heat they absorb or reflect. Colors with high solar reflectance reflect more heat, while those with lower reflectance absorb more heat. By picking colors with high solar reflectance, we can keep our buildings and their surrounding environments cooler! 

• White & desert colors: The external walls of Culdesac's buildings are covered in white and desert colors, which have a high solar reflective index! However, they have to strike a balance between solar reflectance and making sure that heat isn't reflected back onto pedestrians. 

These SRI scores and colors were adapted from Sweets Construction catalog.

Reflective roofs: Roofs can use paints with higher solar reflectance, since there's no risk of the heat being reflected onto people or surrounding buildings. Depending on the exact color and material, cool roofs can be up to 50 degrees F cooler! 

The entire Culdesac site is designed for a 100 year, 2-hour megaflood. A lot of this is made possible by their use of permeable ground materials and designs! (But don't worry — it's still very sturdy. The materials are graded for emergency vehicles.)

• Pavers + decomposed granite: Though there's exciting new types of permeable concrete, some more classic materials can help with stormwater absorption. Pavers and decomposed granite are two perfect examples, since they naturally help water seep through the ground rather than accumulating at the surface. 

• Dry wells & bioswales: One of the main arguments against using trees for urban cooling hinges on their water needs. To mitigate the irrigation needs of their greenery and simultaneously reduce the risk of flooding, Culdesac has installed dry wells and bioswales. In an environment that deals with both extreme heat and heavy rainfall, these solutions are a win/win, helping to recharge and filter groundwater while reducing run-off. 

Water features are a great way to cool the urban environment, especially in dry regions. Water fountains are especially effective, since the movement of the water and high surface area allows for more evaporation! 

• Water fountains: Intermittently scattered throughout the site's courtyards, water fountains provide beauty, cooling, and places to gather. They can cool the surrounding air by more than 5 degrees F, and you can feel the cooling effects more than 100 feet away! 

There is the natural question of how people get around, especially in one of America's most car-dependent metropolitan areas. Since Culdesac hasn't opened its doors to residents yet, we can't be sure how this will play out, but Culdesac's team has a thoughtful set of transportation solutions that create environmental and health co-benefits. 

• Public transit: Culdesac Tempe's site is located right at a stop for the new light rail line and residents get free rides! This not only makes mobility easy for residents, but also makes the Culdesac site (with its restaurant and grocery store) easily accessible to the broader community. 

• Micromobility: Residents will also have access to 1,000+ bike parking spaces and discounts on Bird scooters. These active transportation options not only reduce emissions, but also get your heart pumping! We're especially excited about the team's promotion of e-bikes as a mobility tool. (If you've seen CEO Ryan Johnson’s twitter account, you know what we mean). 

• Ride sharing: So what do residents do for trips where cars are still the best option? They can use the Lyft pink memberships or rent an electric car through Envoy — both built-in perks for Culdesac residents! 

As a quick summary, here's what this means in terms of climate resilience: 

But putting solutions to work is easier said than done. 

Projects like Culdesac show that putting solutions to work is not only possible, but just plain favorable. Cities, developers, and residents don’t need to be ideologically driven or deeply moved by climate change to integrate these elements — they simply make a community more pleasant for everyone. 

And as excited as we are about Culdesac's climate solutions, their 17-acre pilot site is only a drop in the bucket of what we need. Though Culdesac's team has worked hard to develop a great relationship with Tempe's government and community members, it can only house ~1,000 people, and the need for this type of resilient housing is much greater than that.

But change begins somewhere, right? Our hope is that by showing all the perks of these climate solutions, we can drive both supply and demand of these types of developments. And in the meantime, Culdesac is expanding their reach — they just announced their next site at Murphy Crossing in Atlanta, which will be a mixed-use development with both market rate and affordable housing. We need to build our way towards a more beautiful, climate resilient future. So the more developments we get like this, the better. 

To that end, we'll be continuing to explore how Culdesac actually took these ideas from blueprints to buildings. Implementation of solutions can be incredibly difficult, especially when you're building entire neighborhoods from scratch. In an upcoming post, we’ll go over the elements that came together to make Culdesac’s pace of implementation possible. We’ll cover the Tesla Effect, the tactic factor, and the collaborative ethos that drove this development. We all have something to learn from Culdesac's secret sauce, because more people should take on big, ambitious projects like this one! 

Finally, we'll leave you with some food for thought. During our tour of the Culdesac site, we asked Anders Engnell (the team's lead of Urban Planning and Construction) how they came up with the community's design features. 

His answer was simple: "Well, we asked ourselves this: What if we un-paved paradise?" 

Lyn touring the Culdesac construction site with Anders, Culdesac’s head of Urban Planning and Construction! 

Location check: Lyn will be doing site visits in Los Angeles and Long Beach this week. Anson will be bearing snowstorms in Waterloo/Toronto for the next couple weeks before heading to Vancouver! Sonam is in Palm Springs, CA, visiting America's first commercial wind farm, which turned 40 this year. She's a big fan! (get it?) 

Special thanks to James for hosting in Tempe + knowing the best places in town to get fried chicken, and to the entire Culdesac team for making time for interviews and site visits!

If this wasn’t enough climate reading for you, check out our dear friend Nadia’s piece on climate tribes, which she just released (and includes a shoutout to Climate Industrialism!).

by Sonam Velani, Lyn Stoler, & Anson Yu