Design Standards for U.S. Transportation Infrastructure: Implications of Change

his paper examines the changes to engineering design practice that might occur given climate-induced changes in environmental factors. A project design is separated into the individual components that might be affected by changing environmental conditions: subsurface conditions, materials specifications, cross sections and standard dimensions, drainage and erosion, structures and location engineering. A typical engineering design process including the use of design standards is described. The origin and use of design standards and guidance is presented with an assessment of how robust and flexible they are to incorporating climateinduced changes. Climate change-induced design factors include temperature change, precipitation and water levels, wind loads, and storm surges and wave heights. Both the shortand long-term implications of these changing environmental factors are examined. The paper concludes that there is a need for a broader systems perspective in looking at network-oriented infrastructure design to determine what design factors, if any, should be included to reflect network interdependencies. Risk-oriented, probabilistic design procedures should be used when defining design characteristics of components that could be affected by changing environmental factors. The design standard and guidance approach to current practice should be assessed to see how such procedures could be enhanced or further introduced into standard practice. The design considerations relating to the presence of water and the additional forces applied to engineering structures due to wave actions and storm surges appear to be the most pressing in the shorter term. In the longer term, temperature changes, increasing range of temperatures during a typical year and wind loads become important additional considerations. Non-design standard strategies for considering risk-oriented designs should be examined closely in a broader assessment of how to respond to climate change. The linkage between infrastructure provision and land use development patterns needs to be considered very carefully because of the development-inducing influence of infrastructure provision (and thus the corresponding multiplier of hazardous conditions to human population in the case of an extreme event). One of the most productive avenues of research might be the application of “smart” technologies to infrastructure to provide flexible responses to changing environmental conditions. There is clearly a need for research on the potential impacts of climate change on infrastructure design. This is a serious gap and a missing step for gaining agreement from the professional community that the issue deserves attention.