WWW.ACPA.ORG 17 SPRING // 2024 “Another consideration is that vehicles, especially big rigs, drip oil and these drips penetrate asphalt and cause deterioration. Concrete is not susceptible to deterioration when exposed to oil, so this contributes to its durability,” said Caltrans Transportation Engineer Inderpal Gill. “Experience has shown us that those oil drips are really detrimental. The damage they cause not only drives up maintenance costs but they also negatively affect a visitor’s experience of the rest area, so avoiding the damage by using concrete will be a benefit,” added Caltrans Resident Engineer Zubair Anwar. Resilient, long-life concrete pavement is inherently sustainable. Plus, an additional sustainability benefit of concrete pavement is that it possesses a high albedo, which means it reflects large amounts of light energy from the sun back into the atmosphere instead of absorbing it. As a result, it remains cooler than other pavement surfaces. “Concrete’s coolness was another feature that made it a desirable choice for the Erreca rest area,” said Smith. “By absorbing less energy due to the reflectivity of the pavement, it lowers the ambient air temperatures and reduces the urban heat island effect.” Upgrading utilities was another major way Caltrans achieved sustainability on the J.C. Erreca SRRA project, with a focus on low water usage and low power demand. This conservation method will serve as a working model for the rest area visitors. Caltrans will also install solar electrical generation facilities on the site. Gray water (wastewater from the sinks) will be captured and treated in the site’s wastewater facility, then reused for flushing toilets. Potable water will be sourced from surface water and treated using an ultrafiltration system. (Ultrafiltration processes use superfine membranes to mechanically filter very small particulates out of water.) “The use of filtered surface water is important because it reduces reliance on the state water system during a time when we’ve been hit with a severe drought and consumers have been asked to make cuts in water usage,” said Birrell. Landscaping was also designed to minimize water use, in keeping with Caltrans’ water conservation strategies, which include indigenous, drought-tolerant plants and the preservation of existing vegetation. Designing for the Future but Remembering the Past Like many state departments of transportation, Caltrans is designing its SRRAs to architecturally express what makes a specific region unique. “The region where the Erreca rest area is located used to host Basque sheep herders—in fact, it takes its name from one of those men. To honor the area’s history, we have installed graphics on the wall that are inspired by the brands those herders used on their sheep,” said Birrell. John “Chuck” Erreca was the son of a Basque rancher and went on to be elected as mayor of Los Banos and then appointed to the highway commission. While in that post, he became a champion of roadside rest stops. Birrell continued, “We are also installing an interpretive display discussing the region’s Basque history, and the design of the paving in the main plaza was modeled on aerial views of farmland to the east.” Another informational display on the site highlights facts about the California Aqueduct, a concrete channel that carries water from Northern California to Southern California and is an important part of the State Water Project, supplying water for agriculture, homes and businesses. The aqueduct runs parallel to I-5 and adjacent to the Erreca rest area, making it ideal for educating visitors on the aqueduct and the State Water Project. The total project cost for the J.C. Erreca SRRA Project is $37 million. Experience gained during its construction will carry forward, informing future rest stop designs and improving sustainability across the system. Viewing the project, Smith observed, “Caltrans is moving the needle on sustainability and getting results.” Fig. 3: Concrete helped the project team improve structural capacity and aid resistance to deterioration from oil drips. RETHINKING AND REPAVING
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