Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
1 SUMMARY This research project determined the state-of-practice in highway construction sustainability and produced a Guidebook to be used by practitioners as an aid in communicating, implementing, and evaluating sustainable highway construction. The Guidebook and its description are in NCHRP Research Report 916. NCHRP Web-Only Document 262 describes the research process and outcomes used to develop the Guidebook. Key activities in developing the Guidebook were: ï· Definition and frameworks. Defined sustainability for highway construction and produced a framework for sustainability and one for construction to further categorize each. ï· Literature review. Reviewed existing literature encompassing 196 published sources that identified 64 sustainable construction practices (SCPs). ï· Survey. Online industry survey with 367 responses that identified 57 SCPs and collected information on sustainability perceptions within the highway construction industry. ï· Interviews. Twenty-six interviews of industry personnel that identified 32 SCPs and captured information not readily available in the literature or the online survey. ï· Workshop. A one-day workshop with 27 attendees (four research team members, six panel members, and 17 industry attendees) used to gather industry feedback on a preliminary list of SCPs, the proposed frameworks for sustainability and construction, and Guidebook organization and content. ï· SCPs rating survey. A survey administered to the panel members, workshop invitees and participants, and the research team to numerically assess the effort and impact of each SCP. ï· Guidebook development. Writing of the Guidebook. ï· Future research needs. An assessment of future impactful sustainable highway construction research needs. ï· Potential Implementation directions. Ideas for potential impactful implementation of the Guidebook. Key findings from the research process were: Sustainability defined within the construction context. Sustainable highway construction practices (SCPs) are construction practices with the ability to (1) build highways, (2) preserve and restore surrounding ecosystems, (3) meet basic human needs such as equity, employment, health, safety, and happiness, and (4) manage resources wisely (including, but not limited to, money). This definition still does not lend itself to an easy determination of what construction practices might be defined as SCPs to ultimately be included in the Guidebook. Therefore, a more straightforward practical inclusion criterion was used: an SCP is a construction practice done to benefit people and/or the environment that (1) goes beyond the required national regulatory minimum or standard practice, or that (2) shows innovation in meeting these minimums and standards.
2 Sustainability framework. A framework that defines specific sustainability subtopics assists in communicating the full breadth of ideas sustainability addresses and can use common language to refer to specific components (TABLE 1). TABLE 1. Framework for Roadway Sustainability Rating Systems Adapted to Sustainable Highway Construction Dimension Category Indicator Human Wellbeing Basic Needs Food Drink Sanitation Health & Happiness Healthy life Safety Culture and History Aesthetics Personal & Social Development Education Equality Income Distribution Good Governance Environmental Wellbeing Nature & Environment Clean Air Clean Water Clean Land Ecological Resources Natural Resources Water Resources Consumption Climate & Energy Renewable Energy GHG Emissions Economic Wellbeing External Economy Financial Impact Employment Project Economy Cost-Benefit Highway Construction Framework. A framework that categorizes highway construction into smaller focused topics (TABLE 2).
3 TABLE 2. Framework for Highway Construction Level Category Project Delivery Project Delivery Method Financing Project Procurement Contract Project Scheduling Estimating Project Controls & Administration Earthwork Drainage/Sewer/Water Structures Pavement (base, hard surface) Work Zone Traffic Control Materials Safety Employment Training Community and health Noise Light Constructability Quality Equipment Utilities Landscaping Views on sustainability. ï· Sustainability is most associated with reducing consumption and durability/endurance concepts (e.g., long life, lasts a long time, etc.). This is a rather narrow definition when compared to sustainability research (Anderson 2008). ï· Sustainability impacts of highway projects are most often discussed as reducing negative impacts to humans and/or the environment. ï· Sustainability is most often thought of as a core value of respondentsâ company/organization. ï· Contractors are likely to implement SCPs that directly reduce their own costs; other practices must be compensated for by the owner. ï· There is no leading entity in sustainable highway construction. ï· Most SCPs can provide benefit if used in the proper context. There is little guidance on procuring sustainability in highway construction. Interview and workshop feedback indicated that there is no generally recognized approach to procure sustainability in highway construction.
4 Currently, in construction, sustainability is not as important as cost or schedule. Survey, interview and workshop findings addressed emphasizing sustainability through organizational support, holding pre-construction meetings, creating tracking plans, and providing feedback on sustainability efforts after construction. This may be because construction projects do not value sustainability as much as cost and schedule. As a result, sustainability goals and features may not be tracked or may be ignored/eliminated in favor of cost or schedule goals. Isolating construction from other highway sustainability contributors is difficult. Many comments during the survey, interviews and workshop addressed planning and design elements that we believe to be outside the scope of this project. This may be because it is difficult to isolate the contribution of a single transportation system component (construction) to sustainability without addressing other system component (e.g., planning, design, maintenance, operation, salvage) contributions. A programmatic approach may be better than one-off attempts. One series of comments in the workshop advocated for a programmatic approach to sustainable materials procurement rather than a project-by-project approach. While we have not found documented research in this area, this may well be a more economical and lasting approach to integrating sustainability into materials procurement.
