The Texas Transportation Institute (TTI) conducts research into various roadside applications to provide sponsors with a more diverse set of tools and options to ensure a more sustainable roadside environment. Areas researched include water harvesting applications, grass communities and their successional processes, improved vegetation through soil restoration using compost and other organic materials, and minimizing the effect of construction on existing trees and other sensitive landforms.
Erosion and Sediment Control
TTI‘s Hydraulics, Sedimentation and Erosion Control Laboratory (HSECL) is a state-of-the-art facility used by Texas and other states to improve our nation’s water quality. Products, materials, devices and methods used for storm water quality improvement, erosion and sediment control and the design and management of sustainable roadsides are all researched at the facility. Those results are then shared with other state transportation agencies. TTI‘s facility is recognized as one of the premiere facilities of its type in the world.
Recycling of Roadways
Full-depth reclamation (FDR) is a rehabilitation technique that involves pulverizing the existing roadway materials, mixing it with a stabilizing agent and using it to form a foundation layer for the new roadway. FDR provides structural benefit to the new roadway, conserves raw materials and quickly returns the facility to service. Not only does FDR benefit the environment by recycling 100 percent of the materials used in a roadway, it’s also an efficient, cost-effective re-use of roadway materials.
Warm Mix Asphalt
Researchers at TTI have applied lessons from Europe to lower the temperature of asphalt by 35 to 100°F prior to application. Warm (as opposed to hot) mix asphalt reduces on-site emissions, lowers energy costs for the contractor and expedites construction time. This process can significantly impact transportation construction projects in and around air quality nonattainment areas. With warm mix technology, asphalt production plants can manufacture more tonnage without increasing plant emissions, a serious concern in an age of climate change.
Emissions Testing and Monitoring
TTI‘s Transportation Modeling Program uses applied mathematics to help urban areas model their mobile source emissions to determine how to demonstrate conformity with Environmental Protection Agency (EPA) emissions standards. Researchers in this program are currently leading the way in transitioning how EPA tests emissions (see related story).
Sustainability in Transportation Planning
TTI recently completed a project to develop sustainability objectives for Texas Department of Transportation to consider in its strategic planning process. Researchers created 13 sustainable transportation performance measures and a methodology for benchmarking them, as well as derived a method for combining those measures into one index for comparative purposes. TTI was recently awarded a National Cooperative Highway Research Program project to examine similar issues at the national level.
Improved Transportation Operations
TTI works with local, state and federal agencies to improve traffic operations through better management of the transportation system. Software programs developed by TTI, like PASSER V, help optimize traffic flow and reduce congestion, thereby mitigating traffic’s impact on the environment. TTI is currently pursuing new initiatives such as integrated corridor management and active traffic management, green transportation corridors where design and operation of transportation corridors maximize the ability to move people and vehicles, everything from mobility measures to reduce congestion to integrated corridor management—in short, where all aspects of transportation are coordinated to minimize the environmental impact of operating the system.
Roadside Designs for Aesthetics and Accessibility
TTI projects have assisted in the revitalization of older, established communities and small towns by redesigning the roadside for accessibility compliance and incorporating streetscape components such as public spaces, pedestrian and bicycle circulation, aesthetic lighting, street trees, landscape planters, and public art.
Land Use and Planning Partnerships
Regional planning aimed at better coordinating local transportation systems, rerouting hazardous materials away from urban population centers and better coordinating hurricane evacuations is only a few of the land use and planning areas in which TTI researchers support sponsor goals. One recent project involved TTI working in India to trap methane gas produced by landfills for conversion into liquefied natural gas for use as fuel.
Drive-In Environmental Research Chamber
Opening in January 2010, TTI‘s new facility is the largest of its kind in the United States. Temperature and humidity are controlled in the 75 by 22 by 22 foot chamber, which will help test, among other things, onboard idle-reduction technologies for semi trucks. Other areas for testing include fuel consumption, hybrid technologies, pollutants entering vehicles and various applications related to emissions (see related story).