Architekton's Tempe Transportation Center is a place designed for interaction and community. The architectural form reflects the special nature of gathering spaces juxtaposed against the efficient, rational organization of uses that serve city residents and the Phoenix metropolitan region. The Tempe Transportation Center is the centerpiece of Tempe’s award-winning transportation program, geared to becoming the social and transportation hub. The complexities of this triangular urban site include a busy light rail platform, Hayden Butte, ASU Sun Devil Stadium and the Tempe Police/Courts/Jail complex. The historic downtown and expansive ASU campus (69,000 students) are served by the amenities and transportation options of the Transportation Center, a strategic hub for the new 20-mile METRO light rail system, local and regional bus, Zipcar, and Arizona’s first bike station.
Building placement was carefully considered to respect, maintain and frame views of Hayden Butte, a sacred cultural site for Native Americans. The concept of providing a variety of transportation options in the dense downtown, with food, retail and service amenities enhancing user comfort, health and safety led to a facility that integrates with the man-made environment while encompassing goals of economic, social and environmental sustainability. Paving materials reflect the color of the mountain and the desert adapted and native plant palette complements the existing landscape. The new design of the transit shelters acknowledges the need for vertical shade panels in the desert Southwest. Vines are supported to enhance ventilation and cool the air, while translucent glass panels provide deep shade and divert rain. Broad canopy shade trees will mature to provide relief from the sun while collecting and redirecting water, cooling the paving and reducing the urban heat island effect.
The 40,300 sf, three-story building houses the city’s Transportation Offices, Traffic Management Center, Community Room, Transit Store, and Arizona’s first bike station. Ground floor retail and food service provide amenities for bus and rail patrons, ASU students and visitors. The Bicycle Cellar provides bike racks and four changing rooms with showers and lockers, offering bike sales, rentals, repairs and accessories. This successful design can be replicated at future multi-modal sites to reduce carbon and support community health.
The high-performance building envelope and integrated systems were developed and tested with computer modeling, resulting in a 52% reduction of energy use. This is accomplished in part with a solar veil that protects the east facing steel and glazing from dawn to noon to prevent morning heat gain. The loose weave fabric screens are deployed at daybreak and retracted at noon and can be manually adjusted from the interior by remote control. The shades automatically retract during high winds, responding to roof mounted sensors. Solar panels provide hot water to the building, and conduit is in place for future installation of photovoltaic panels on the roof.
Quality materials were used to develop a building with a useful life of 80-100 years. The floor plans place support uses (exit stairs, mechanical, copy and storage rooms, lunch room) along the west wall, protecting the daily-occupied office area and creating a flexible space that can change over time. The 2’x2’ concrete panels in the raised floor can be removed and rearranged to accommodate changes in office layouts and the DIRTT interior glass and steel office wall system can be removed, stored and reconfigured as functions change, eliminating demolition waste and reducing time of construction.
The building includes a number of innovations, including the first desert green roof on an urban office/commercial building. The roof is a visual extension of the mountain and the plaza, visible from Hayden Butte and nearby urban buildings. The 12” soil mix and low maintenance plants stabilize the temperature of the structure in the severe summer heat, buffer noise from overhead air traffic, preserve the roof membrane and filter rain water.
A 15,000-gallon stormwater recovery system collects water from the roof, the adjacent Police sallyport, and from routine power washing of the bus lane and the public plaza. Recycled water is used for drip irrigation to low-water desert plants and trees on site. Waterless urinals and low flow fixtures are standard and dual flush toilets fill with graywater from showers and sinks. A water conditioning system maximizes reuse of water in the chiller.
Operable windows and large sliding doors provide alternative cooling opportunities and a connection with the natural environment. The north and south elevations of the Community Room open to create an elevated gathering space recalling the historic “Arizona room” common before the use of air conditioning. Daylight takes the place of overhead electric fixtures throughout most of the building. Task lighting and an LED lamp are installed at each workstation and office.
The complexities of this triangular urban site make for a design challenge that forces the study of multiple programed interactions. Leading to a security criteria for the reconstructed Police sallyport (accessing the below-grade jail), restricting windows in the west-facing masonry wall, impacting exterior lighting levels, and modified building access. The complex natural slope of the property required sensitive execution to manage bus turning movements, drainage and user accessibility. The concept of providing a variety of transportation options in the dense downtown, with food, retail and service amenities enhancing user comfort, health and safety led to a facility that integrates with the man-made environment while encompassing goals of economic, social and environmental sustainability. Operating and maintaining the building requires education and prompts individuals to question procedures and policies that impede environmental preservation.
The climate responsive design and recycled content materials are unveiled to visitors through an educational interactive Green Touchscreen on the public plaza, displaying the design process, construction methods, LEED strategies, and building systems. A documentary film of the project process includes archeological discoveries of historic Hohokam structures and artifacts (600 AD to 1450 AD) from the site that inform current conversations of food production and water conservation in the desert.
The addition of the vegetated roof supports native birds, bees and butterflies. Construction waste was reduced by 94%, and natural resources were preserved by use of local, rapidly renewable, recycled and recyclable material content. Carpeting and furnishings are GreenGuard certified. The first double-chambered garbage receptacle was installed, compacting recyclables on one side and trash on the other to reduce multiple pickups, fuel consumption and man-hours. Low or no VOC paints and non-toxic glues and products, under floor air distribution, natural light and views enhance employee health and productivity. Installation of energy efficient water pumps, motors, air exchanger, plate-frame heat exchanger, sensors, lights and LED exit signs yielded an APS rebate of over $19,000, in addition to the annual operational energy savings. The project is seeking LEED Platinum certification.
The desire to inform the community about sustainability led to the first “Reuse/Recycle” signage program in the nation, utilizing left over finish materials, construction scrap, old bus tires and abandoned bicycles. Interpretive signage and educational wall displays expand opportunities to learn about green building and products. Public art is integrated in the building design, incorporating recycled glass slag in courtyard walls lit from within by colorful LED light displays that change over time. Etched granite pavers in the plaza are an artist’s interpretation of how the site was used throughout its history.
The grand opening of the Tempe Transportation Center in December 2008 coincided with the opening of the new 20-mile METRO light rail system, attracting visitors from across the country. The local community has been anxious to learn about the building and the sustainable strategies utilized for design, procurement, construction, operations, and maintenance. Over 1,200 people have toured the building during construction and through the first six months post-occupancy. The ongoing educational opportunity will result from testing, monitoring and refining the systems and strategies of operation. Building data will be collected to track reduction in potable water use, amount of recycled stormwater and graywater used, and the performance of energy systems. A challenge to improve efficiency and reduce operational costs annually will establish new benchmarks for future projects in arid climates around the world.