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Sustainability Springs from NTTA’s Green Initiatives As April 22 marked the country’s annual Earth Day celebration, consumers understandably associate roads and traffic with emissions. However, the NTTA is working to change this perspective when it comes to toll roads in North Texas. By designing, constructing and maintaining its tollways in ways that ensure environmental sustainability, the NTTA minimizes impacts on natural resources on Earth Day and every day.
Air Quality
The NTTA is doing its part to reduce ozone-causing traffic congestion through cashless tolling, also known as all-electronic toll collection. Converting to cashless tolling removes idling, acceleration and deceleration at toll plazas, reducing fuel consumption by 6-12 percent and resulting in a 45-80 percent reduction of vehicle emissions. Additionally, the tolling equipment and overhead structures, known as toll gantries, consume less energy than traditional toll booths. The Authority completed its system-wide transition to cashless tolling in December 2010, with the conversion of the Dallas North Tollway, Addison Airport Toll Tunnel and the Mountain Creek Lake Bridge. The President George Bush Turnpike already switched in 2009, and the Sam Rayburn Tollway and the Lewisville Lake Toll Bridge were among the first NTTA facilities to be designed and built to feature cashless tolling.
Fuel Consumption
The NTTA has made another significant contribution to improving air quality by replacing its operations fleet with hybrid, flex fuel, and low sulfur diesel vehicles. With 228 vehicles supporting 705 lane miles in what the American Lung Association deems the seventh most ozone-polluted metropolitan area in the country, the NTTA recognizes its unique opportunity to positively impact the region. Nearly 43 percent of NTTA vehicles use alternative fuels, with 71 of those joining the fleet since 2008. That total includes 32 hybrid vehicles, 16 flex fuel vehicles and 46 low sulfur diesel vehicles equipped with regeneration systems.
Water Quality
The NTTA protects water resources through aggressive storm water management and clean-up programs to keep litter and pollutants out of the local water supply. Complete turf coverage to reduce erosion and limited use of herbicides and pesticides also help maintain water quality. Additionally, the NTTA uses a vehicle wash area that drains directly into an oil/water separator.
The NTTA’s storm water management and cleanup program received a Phase I Municipal Separate Storm Sewer System permit by the Texas Commission on Environmental Quality. This permit requires management of storm water and runoff of project-related materials and trash during construction to prevent contaminants from entering surface water. The NTTA is one of the first toll road agencies to receive this level of permitting.
Water Conservation & Xeriscaping
To conserve water resources, NTTA roads feature native, drought-tolerant plants and grasses when possible to aid in tree and shrub sustainability and to reduce maintenance costs. The NTTA utilizes a smart irrigation system, which adjusts run times based on weather conditions and eliminates run-off. In 2007 alone, the NTTA’s smart water landscape program saved almost 50 percent, or approximately 11.7 million gallons of water. The trees and native plans along the roadside also help improve air quality, reduce roadway heat and prevent erosion and runoff.
Additionally, NTTA is taking steps to replace woodlands and wildlife habitat impacted by construction of the George Bush Turnpike Eastern Extension. We’ve also established a maintenance program to protect existing and replaced trees and shrubs.
Environmentally Friendly Materials
The natural looking uncoated concrete and weathering steel that the NTTA uses on all new corridors is more environmentally friendly than coated elements. By using uncoated concrete and weathering steel, the NTTA provides sustainable solutions, and it also realizes long-term cost savings since uncoated elements are less expensive to maintain. Painted concrete or other materials must be resurfaced periodically, which releases volatile organic compounds (VOCs) into the air. Plus, related construction zones increase traffic congestion, further compounding the air quality issues over time.
The NTTA used recycled material in the construction of the new interchange at the Sam Rayburn Tollway and U.S. Highway 75 to minimize the project’s impact on the environment. Three concrete recycling machines were set up on site to crush and repurpose existing asphalt, recycling landfill material, cutting costs and saving time in the construction process.
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