Green Streets and Highways 2010: An Interactive Conference on the State of the Art and How to Achieve Sustainable Outcomes

The Mercer Corridor Project will be an example for how integration of land use with transportation will transform a neighborhood into a more sustainable development. Implementing this requires strong partnerships, committed leadership, and clear objectives. Traditional design related to relieving congestion puts greater value on infrastructure that provides wide streets, high speeds, and limited access without considering elements that would make a community more livable, walkable, and sustainable. In absence of formal guidance for encouraging sustainable practices in design, materials, and construction, substantial infrastructure projects like arterial roadway reconstruction become "lost opportunities" to positively impact climate change. In evaluating solutions, other performance metrics related to livability, walkability, and interaction with land use are often secondary or rely more on subjective or qualitative information. The City of Seattle's voluntary commitment in 2005 to meeting greenhouse gas reduction targets—consistent with the Kyoto Protocols—provided direction for developing infrastructure to help meet those targets. Developing a dense urban neighborhood adjacent to Downtown and served with a streetcar along South Lake Union furthers the City's objectives toward a more sustainable neighborhood supported by sustainable travel choices. This paper explores the methodical approach to evaluating and creating project development tools to support City sustainability objectives; it also reviews the outcomes of applying these tools on the Mercer Corridor Project, which is currently under construction. As part of the design process, tools and applications including a sustainability workshop were developed to identify the broadest range of sustainability elements and test them on the preliminary Mercer Corridor design. Because of its strong partnership, readiness for construction, transformative impact on community, commitment to economic revitalization, and sustainability, the Mercer Corridor Project was one of only two projects in Washington State to receive Transportation Investment Generating Economic Recovery (TIGER) grants. TIGER grant funding, awarded in February 2010, has allowed this project and its sustainable design elements to start construction in the spring 2010. This paper describes workshop elements that were successful, why some were not, and lessons learned during implementation.

The emphasis of the paper is to highlight the cooperative agency and community sustainability initiatives created and set forth by the Denver Strategic Transportation Plan and how these initiatives are influencing current projects. The Denver Strategic Transportation Plan (STP) project team included Denver Public Works staff, engineering and transportation consultants, an advisory committee and a technical committee. It also incorporated vast input from Denver residents. The STP incorporates previous city planning efforts into one document and moves forward to create a great and livable city for now and in the future. This is done by developing a multimodal transportation system to support a livable, connected and sustainable city. The project team created 12 travel sheds, which are study areas defined by geographical boundaries that have characteristics and facilities serving similar travel patterns. The East Side travel shed has recently become a mobility study that takes the STP initiatives to create project-based solutions for its short- and long-term transportation needs. The mobility study is focusing on multi-modal problems, not just vehicle congestion. The project team is looking at gaps within the overall transportation system that are hindering alternative transportation modes.

The Laàloa Avenue Extension is a highly controversial County of Hawaiì (County) project involving the extension of Laàloa Avenue from its current terminus to Kuakini Highway. The County of Hawaiì, wanting to avoid further delays and legal challenges, employed a Context Sensitive Solutions (CSS) approach to develop a consensus solution for the roadway extension. As part of the CSS process, an Advisory Group consisting of 20 members representing a wide range of stakeholder interests was established and led through the CSS process. Through a series of structured, facilitated, meetings the Advisory Group identified key issues and goals, prioritized these elements to identify additional alternatives for consideration. Employing CSS allowed the County of Hawaiì to employ an organized decision-making process that fostered constructive dialog and consensus building with the community and highlighted the power of the community's input to find solutions and maintain project momentum.

This paper describes Oakland County's innovative planning tool for Context Sensitive Solutions (CSS) based transportation and community planning using a CD educational tool. Oakland County, Michigan offers cosmopolitan urban centers, lakefront living, historic town centers, and natural country settings within close proximity to an array of employment and recreational opportunities. Strengthening this diversity is critical to maintaining Oakland County's competitive edge and high quality of life. Parsons Brinckerhoff (PB) provided technical assistance to Oakland County Planning & Economic Development Services in the development of an interactive CD educational tool to provide an introduction to Oakland County's diverse living environments, historical development patterns, and resources that can maintain and strengthen that diversity. The tool is also an informational primer on CSS and will be used to educate local government leaders and the public on methods to develop transportation projects that fit into the County's physical settings.

Context Sensitive Solutions (CSS) provides a systematic and comprehensive approach to project development from inception and planning through operations and maintenance. The ability to categorize and measure the benefits of CSS projects is vital to the long-term success of this approach. The paper presents a framework for transportation officials and professionals that allows for the comprehensive quantification of benefits resulting from CSS through all phases of project development. A fundamental aspect of this framework is the identification of CSS action principles and their potential benefits. A matrix that correlates benefits to specific CSS principles was generated to allow for the development of appropriate metric indicators for each benefit. Guidelines for benefit analysis have been developed to provide transportation agencies with a set of recommended practices for assessing benefits. The guidelines emphasize the fact that CSS is a principle-driven, benefit-justified effort that can enhance an agency's goals and interaction with stakeholders and the public. The need exists to analyze and measure the benefits of CSS and its impact on projects (e.g. cost and delay) in order to demonstrate a best use of agency resources.

Urban goods movement is stimulated by the needs of business and commerce, but is also greatly influenced by growth in population. No city can function without the ability to efficiently move goods. Considering this fact and the growth that many regions are experiencing in population and goods movement, planners must place more emphasis on the freight-related needs of their transportation system. In order to maintain and enhance the economic vitality and quality of life of any thriving city, steps must be taken to manage the current level of freight activity and prepare for the increased activity that will result from sustained growth. As stated in the 2003 Talking Freight Seminar Series Presentation, "Freight planning is somewhat different from passenger travel planning...Elected officials do not always give high priority to freight vehicles for planning." Traditionally, planners have overlooked the freight component of the transportation system choosing, instead, to focus on the movement of people. Therefore, freight planning efforts have lagged behind other transportation initiatives. To ensure the economic sustainability of their region, planners must now find the best methods to seamlessly incorporate the growing volume of freight into their transportation network. The goal of this project was to produce an informational package that would provide insight into previously implemented strategies in the field of urban goods movement. Through an extensive literature review, input from the Working Group consisting of freight professionals from both the private and public sector established for the project, and other data collections efforts, Street Smarts identified several specific projects that would most benefit others undertaking freight planning efforts. As a result, four case studies were prepared, documenting notable practices in urban goods movement: New York, Los Angeles, Orlando, and Washington, DC. The case studies produced for this project provide information on freight-related initiatives that focus on mitigating congestion caused by, as well as improving the efficiency of, commercial vehicles in urban areas. By describing specific projects, offering the lessons learned during implementation, and providing insight on the transferability to different jurisdictions, the case studies will serve as a wonderful toolbox for planners everywhere.

The City of Pearland (COP), located in Brazoria County, Texas, has witnessed an explosive population growth from 19,000 residents two decades ago to now over 92,000 residents. A critical link in COP's mobility is FM 518, a 4-lane roadway providing access and connectivity through COP and neighboring cities. The study corridor consists of a 2-mile segment of FM 518 with 11 signalized intersections providing access to a rapidly growing suburban commercial and residential district. FM 518 is among the heavily traveled arterial corridors within suburban Greater Houston Area with average peak hour flows over 3,600 vph and 4,200 vph on weekdays and Saturdays respectively. Prior to implementation of improvements, the corridor operated poorly with Level-of-Service E/F conditions, peak directional average travel time of 16 minutes, and 13 mph average speeds in the study area. COP, in collective local agency partnership with the Texas Department of Transportation (TxDOT) and AECOM identified cost-effective traffic engineering strategies, and design and operational improvements. A phased implementation of strategies within a constrained budget and schedule resulted in optimal utilization and efficiency of infrastructure. Corridor operations significantly improved with 62 percent increase in average speeds and 55 percent reduction (8 minutes savings) in peak directional travel times. The project partnership and efforts successfully improved corridor mobility and access, enhanced business development, and has enriched resident quality of life.

Roundabouts exhibit many of the characteristics of sustainable design: no power consumption by signal indicators; less pavement devoted to roadways; and lower vehicle energy use and emissions. Moreover, they result in lower delay and fewer crashes. Yet many states and local communities are reluctant to use this method of traffic control. The objective of this paper is to evaluate the use of roundabouts as a tool for reducing energy consumption and greenhouse gas emissions. This paper will quantify several sustainable performance measures for roundabouts used in typical applications (in lieu of traffic signals and all-way stop control). Using the City of Boulder as an example, aggregation of sustainable performance measures for a reasonable level of roundabout implementation will be evaluated to quantify the impact of large-scale use of roundabouts on emissions and energy consumption.

Throughout the US and worldwide, great places can be defined as attractive, active, open, walkable, entertaining and full of people. Great places have great streets and great streets have a "place" function. Great streets are accessible, livable, safe, comfortable, and interactive. Over 130 municipalities across the US have complete streets policies. A Contextually Complete Street is a multi-modal complete street reflecting the principles of context sensitivity and sustainability. In a Contextually Complete Street, the stakeholders and context define what is meant by "complete." This paper describes Contextually Complete Street principles and provides examples of these complete street solutions. Common themes of Contextually Complete Streets are explored and tools that can be used in achieving a Contextually Complete Street are highlighted. These tools include road diets, traffic calming, intersection design, designing for pedestrians and bicyclists, transit design features, lane restrictions, and green street options.

Many factors influence one's decision to walk or bike when making a trip. Currently there are limited models available to quantify the demand for walking and biking. This paper describes the basic concepts to estimating non-motorized demand and introduces a new paradigm to quantifying walking and biking trip demand at a parcel level. Looking at non-motorized trips at the parcel level represents a shift towards analyzing activity at a true pedestrian and bike scale. This robust modeling approach is the first of its kind and provides a powerful tool for communities to quantify and compare actual walking and biking demand so that future transportation investments can be evaluated and prioritized. This modeling approach also serves as a tool in conveying how certain land use patterns and infrastructure investments can and do influence the way we travel. The components of the parcel-level, non-motorized model and its application are discussed.

Transportation investments in America throughout history have come at many different scales and from varying funding sources. Over time, investments have varied from public to private sources and back: From the private investments in construction of tolled "turnpikes" to connect the original 13 colonies; to a shift to public investment in the mid-19^th century, best exemplified by Abraham Lincoln's support for "internal Improvements" early in his political career and for railroad construction subsidies later; from private investments in streetcars and streetcar suburbs in the turn of the 20^th century; to the Eisenhower-era public investment in the national interstate highway system. Today, America is again trying to decide how best to fund repairs to its aging transportation infrastructure and what kinds of innovations will be needed in the 21^st Century. The American Society of Civil Engineers reports every year on the state of American infrastructure. The assessment is poor. In 2009, America's best ranking stood at a "C plus" for Solid Waste facilities, while Drinking Water, Inland Waterways, Levees, Roads, and Wastewater infrastructure all stood at the opposite end, each with a "D minus".

Conventional thinking among transportation engineers in the U.S. finds a linear correlation between the number of bicyclists on a roadway and the number of crashes involving bicyclists. However, studies from Europe have found that with increased ridership comes increased safety in the form of a reduction in the number of crashes per cyclist. Our study examines whether these trends can also be found in the U.S., to what extent does this hypothesis hold, and what other factors might be playing a role in the results. We conducted this research in Boulder, Colorado using estimates of average cyclists per day based on turning movement counts on corridors with both high and low bicycle traffic and related that to five years of bicyclist crash data. The data suggest that while bicycle crashes do seem to increase with motor-vehicle volumes, bicycle crashes tend to stay constant — or even decrease — with increased bicycle volumes.

Stormwater runoff from roadways is a source of surface water pollution in North Carolina. The North Carolina Department of Transportation (NCDOT) is required to implement stormwater BMPs in the linear environment. NCDOT has specific interest in runoff from bridge decks, which is often discharged through drainage holes in the deck directly to the stream below. This research focuses on retrofit stormwater BMPs for bridge deck runoff management. Two bioretention cells and a bioswale were constructed in the easement of a bridge deck on I-540 at Mango Creek. One bioretention cell was adequately sized based on current North Carolina design guidance, while the other was undersized by one-half. Undersized bioretention cells could often be used in retrofit situations; therefore, it is important to understand how an undersized bioretention cell performs with respect to hydrology and water quality. Both bioretention cells employed 0.9 m (3 ft) of fill media, and had an internal water storage layer (IWS) of 0.6 m (2 ft). The bioswale was designed to convey the 2-year storm event. Runoff was piped from the northbound and southbound lanes to the bioretention cells and bioswale, respectively. Data collection began in October 2009. Weirs and stage recorders were used to monitor inflow to and outflow from each BMP. Flow-proportional, composite water quality samples were obtained at the inlet and outlet of each BMP. Monitored water quality parameters include TKN, NO_2–3-N, NH₄-N, TN, TP, TSS, Cu, Zn, and Pb. For small storms (those with less than 1 in [2.5 cm] rainfall depth), flow volume reductions for the standard and undersized bioretention cells were 50% and 27%, respectively. This shows the hydrologic importance of sizing bioretention cells appropriately when space is available. Average concentrations of TN (0.74 mg/L), TP (0.12 mg/L), and TSS (31 mg/L) from the bridge decks were relatively low when compared to other highways in North Carolina. Median effluent concentrations for the standard bioretention cell were lower than those for the undersized bioretention cell for all nutrient forms and sediment. Pollutant loads of TN, TP, and TSS were reduced to a much greater extent by the standard bioretention cell due to improved volumetric runoff reductions. The bioswale had similar influent and effluent concentrations for TN, TP, and TSS. Reductions in flow volume for the bioswale were not observed, resulting in poor pollutant load reduction.

There is no industry standard to define a green bridge. Green standards have been successfully implemented in other industries and can be used as a guide for developing a green standard for bridges. The goals of green design include reducing life cycle costs, energy use, greenhouse gas emissions, pollution emissions, waste, and the use of non-renewable resources to sustainable levels. The Greenbridges standard proposed herein is meant to provide a starting point for discussions between bridge professionals and the existing developers of highway and infrastructure sustainability rating systems. Greenbridges has a total of six prerequisites and thirty-nine points grouped into seven categories. The categories are: materials & resources, alternative transportation, project delivery process, construction activity, maintenance & access, environment & water, and energy. Until a standard is available, three primary strategies for reducing environmental impacts of bridge projects are to design for minimum life cycle costs, to use recycled materials to the maximum economical extent, and to provide preferential access to alternative (non-single-occupancy motor vehicles) transportation modes.

The Domestic Scan Program was developed to highlight innovative practices of high-performing transportation agencies that could be beneficially adopted by other interested agencies. The Scan Program provides the opportunity for technology transfer on a relatively economical basis with significant benefits on a national scale. The Clean Water Act (CWA) places requirements on Departments of Transportation (DOTs) for the discharge of stormwater from their systems through the National Pollutant Discharge Elimination System (NPDES). Non-compliance with NPDES permits can impact project design, engineering and construction schedules and increase construction time and costs. Successful compliance with NPDES permits requires the appropriate transfer of information and accountability through multiple phases of project delivery. State DOTs that are under NPDES Municipal Separate Storm Sewer System (MS4) Phase I or Phase II permit coverage are anticipating implementation of the total maximum daily load (TMDL) process which poses potential stormwater permitting concerns based upon the method of implementation chosen and the types of receiving water impairments addressed. This paper summarizes a Domestic Scan for stormwater that occurred in July, 2009. Four primary topics were selected as the subject of this Scan. Benefits of this Scan include better insight into stormwater requirements during the project delivery process, improved compliance with NPDES permits, and reducing project delays associated with NPDES violations and noncompliance. The Scan provided an excellent opportunity to document lessons learned and share experiences to assist individual DOTs in negotiating, developing, implementing and tracking TMDL programs as part of NPDES MS4 compliance.

The City of Santa Monica's Watershed Management Program requires post-construction Best Management Practices (BMPs) for private and public construction projects, both new development and redevelopment (retrofits), to reduce the amount of stormwater runoff and to improve runoff quality entering the Santa Monica Bay. While the city's watershed management program has been and continues to be successful in promoting Low Impact Development (LID) strategies for individual parcel projects, the transportation grid is a harder area to incorporate BMPs. Transportation infrastructure involves other complexities of development, such as underground utilities, grade limitations, parkways, traffic flow and safety vehicle movement. To demonstrate the feasibility of incorporating the green street BMP strategy in an ultra urban, built-out setting, the city obtained a state grant to build such a green street. With this state financial injection, the city retrofitted a hardscaped, landscape-lacking, densely populated, multi-family street surrounded by commercial land uses. The Bicknell Avenue Green Street Project demonstrates how an urban street can be retrofitted with a combination of BMPs, low-volume irrigation and climate-appropriate landscape. The result is an aesthetically attractive, greener street with less impermeable surfaces that infiltrate up to 80% of wet weather flows. The Bicknell Avenue Green Street project featured the use of multiple BMPs within the right of way. This project utilized porous concrete, curb extensions, depressed landscape bio-retention areas, catch basin fossil filter inserts, and underground arched plastic infiltration chambers surrounded by medium sized washed aggregate. These BMP devices were chosen to remove the typical pollutants found within the first-flush rainfall (3/4" storm) and reduce the amount of sediment reaching the infiltration chambers. The finished project treats the flow rate and infiltrates the volume of the runoff generated from the first-flush rainfall. The project was completed in spring 2009 and has been subjected to multiple rain events during the 2009/2010 rainy season. Visual observations of the project after a storm event show that trash, debris and sediment are captured either in the bio-retention areas or in the catch basin fossil filter inserts. Additionally, based on visual observations, runoff within the gutter system is significantly reduced by the time it reaches the public catch basin near the end of the project and runoff can been seen within the catch basins and show that the infiltration basins are being filled. Whenever a jurisdiction plans to retrofit a street or build a new one, LID features must be included in the site design for a green street. By demonstrating the efficiency of a green street along with other green street projects in Santa Monica, the City hopes to set a new standard for Southern California streets and encourage other jurisdictions to "jump on the bandwagon" and replicate this LID strategy. Green streets should become the new standard for transportation infrastructure.

A permeable friction course (PFC) is a 50 mm layer of porous asphalt placed on top of conventional, impermeable pavement. This paper describes a multi-year research effort on the water quality and hydraulic aspects of PFC. Water quality monitoring of three field sites near Austin, Texas showed a 90% reduction of total suspended solids (TSS) compared to conventional pavement. Significant reductions were also observed for total copper, total lead and total zinc, though concentrations of dissolved constituents were not significantly different. The hydraulic properties of PFC are of interest to assess the drainage capacity of the pavement and the effects of clogging. The properties investigated in this study were the porosity and the hydraulic conductivity. Porosity was measured from core specimens and found to range from 0.12 to 0.23. Hydraulic conductivity was also measured from core specimens and ranged from 0.1 to 3 cm/s. A new field method for measuring the in-situ hydraulic conductivity of PFC was developed and compared to the laboratory measurements. Predictions of the water depth on PFC roads are needed to assist designers in selecting a pavement thickness and to evaluate the effects of clogging. A Permeable Friction Course Drainage Code (PERFCODE) was developed to make these predictions. Measured porosities and hydraulic conductivities were used as inputs to PERFCODE. Outputs were the variation of water depth through a storm and the runoff hydrograph. The modeled hydrograph is compared to runoff hydrographs obtained by field measurement.

With limited transportation funding, the completion of timely National Environmental Policy Act (NEPA) studies that can be accepted by the Federal Highway Administration (FHWA) and the Colorado Department of Transportation (CDOT) is an increasingly difficult task. FHWA has developed the planning and environmental linkage (PEL) process, which outlines a process similar to the one required by NEPA yet does not require a project funding commitment. The PEL process is intended to streamline future NEPA studies, saving cost and time. In 2009, Denver conducted a PEL study for Federal Boulevard, an urban, north-south principal arterial roadway that is under the jurisdiction of CDOT as State Highway 88. The goal for the PEL was to develop a Proposed Action designed to: improve safety, increase efficiency for all modes of transportation, relieve traffic congestion, and improve multi-modal mobility (pedestrians, bicycles, public transit, and private/commercial vehicles). The Federal Boulevard PEL case study demonstrates the benefits of a PEL in assessing a project's viability and supporting prioritization for design and funding. This paper discusses the approach that was taken in performing the PEL, the decisions that can be made, the documentation that is required to fulfill PEL requirements, and how the PEL will be used to streamline the NEPA process as the project is funded and implemented. The PEL is a tool that can be used to plan the future vision for a corridor despite a lack of committed funding, all the while providing a streamlined process for successful future NEPA studies.

Recent studies have found that light emitting diode (LED) technology is becoming competitive for streetlight applications with the commonly employed high intensity discharge (HID) light sources such as high pressure sodium (HPS) and metal halide (MH). The expectation is that LED street lighting technology will not only provide more efficient light distribution and increased uniformity, but will also save energy and reduce maintenance costs. Seattle City Light (SCL) has a street lighting system of nearly 84,000 street and area lights that use predominantly HPS light sources. Because of the potential benefits of installing LED luminaires as a replacement for these lights, SCL launched the LED Streetlight Application Assessment Project Pilot Study to evaluate LED luminaires for photometric performance, energy efficiency, economic performance, and the impact of the new lights on SCL streetlight system. Project findings will be used by SCL to develop a strategy for the installation of LED streetlights in developing an energy efficient lighting system. The major elements of this project included LED luminaire selection, simulated photometric performance of selected LED products using AGI32, field photometric performance evaluation at selected test sites, and economic performance evaluation in comparison to HPS luminaires. In addition, since combining LED roadway luminaires with new light control systems provides many new options for overall light control, facilitating maintenance, increasing luminaire life, and further reducing operating costs, a preliminary review of current cutting-edge lighting control systems were explored.

The urban cityscape is covered with man made materials that absorb the suns light. Darkly colored roads and roofs have replaced surface area which was once predominantly vegetated lands. For these reasons summertime ambient temperatures in cities are typically warmer than those of rural areas. This phenomenon is known as the heat island effect. Heat islands lead to increased air conditioning use which puts a strain on a cities energy grid. To supply this extra wattage municipal power plants must work harder and as a result emit more carbon. Therefore, the heat island effect contributes to environmental problems including air quality and climate change. Dark impervious pavements cover a large amount of urban surface area, typically 30–45%. One solution to this problem is the implementation of cool pavement technologies in pavement areas of less stringent structural requirements such as parking lots and low volume roads. Cool pavements are a class of materials that exhibit enhanced cooling by means of increased reflectivity or increased convection. This study correlates heat island effect to climate change as well as outlining the different cool pavement technologies which may help to mitigate climate change effects.

Use of fly ash in concrete reduces the use of natural raw materials, offers benefits of landfill and CO₂ emissions avoidance and therefore contributes to industrial sustainability. This paper presents the results of investigations to determine the various durability aspects of high volume fly ash concrete mixtures, made with ASTM Type I cement and Class C fly ash, yielding a similar 28-day compressive strength to that of Colorado Department of Transportation (CDOT) Class D structural concrete. The durability aspects investigated included the resistance to the chloride-ion penetration (ASTM C 1202), the resistance to the repeated cycles of freezing and thawing (ASTM C 666 Procedure A), and the resistance to the sulfate attack (Mortar bars, ASTM C 1012). It is concluded that the high volume fly ash concrete mixtures are able to exhibit excellent durability characteristics with increased curing time. A concrete mixture with a cementitious material content lower than the CDOT specification and a fly ash content greater than the current CDOT limit, was able to meet Class D structural concrete requirements.

Energy harvesting (also known as power harvesting or energy scavenging) technology allows capturing unused ambient energy such as solar, wind, thermal, strain and kinetic, energy of gas and liquid flows and converting the energy into another form of usable energy. One form of ambient energy available from pavements is thermal energy derived from natural heating of pavements. The goal of this study was to determine if there is a possibility of capturing thermal energy from pavements and storing the energy and using it as alternative power source to other devices. In this paper, a smart material based on regular available Portland cement has been developed which can capture ambient thermal energy available from pavements. The cement composite material acts as a pyroelectric material. The characteristic of pyroelectric material is that a change in temperature creates current flows in the material. Specimens of Portland cement with and without carbon nanofibers have been prepared in the laboratory and tested for various properties, such as, pyroelectric coefficient and dielectric constant. It has been found that plain Portland cement acts as pyroelectric material. Addition of carbon nanofibers increases the pyroelectric behavior of cement. Both dielectric constant and pyroelectric coefficient increase with increase in temperature. The present research indicates that simple material such as Portland cement can be used to capture heat energy from pavements, which can be stored in capacitor for the use of power source to other sensor electronics.

Percolation rates and concentrations of trace elements are presented from leachate collected in pan lysimeters installed beneath roadway sections where fly ash was used to stabilize subgrade or base course. Data from control sections are also presented. Percolation rates from the base of a pavement profile vary seasonally in response to seasonal variations in meteorological conditions. Percolation rates typically range between 0.1–0.5 mm/d, with the average percolation rate falling between 0.1–0.2 mm/d depending on site conditions. Concentrations of six elements (B, Cd, Cr, Cu, Mo, and Zn) in leachate from roadway sections stabilized with fly ash have been elevated compared to concentrations from control sections at all field sites with control sections. Four elements from fly-ash-stabilized materials have been elevated in concentration relative to control section at some sites (As, B, Cd, Cr, and Mo) and have also exceeded MCLs. Both B and Mo persistently exceed MCLs. In contrast, concentrations of Cd and Cr have only exceeded MCLs in the first samples collected (PVF < 0.25), and then have remained well below MCLs.

Foundry sand is a high-quality uniform silica sand that is used to make molds and cores for ferrous and nonferrous metal castings. The metal casting industry annually uses an estimated 100 million tons of foundry sand for production. Over time, foundry sands physically degrade until they are no longer suitable for molds. Consequently, 9 to 10 million tons of sand is discarded each year. However, the discarded foundry sands have remarkably consistent composition and are generally considered a higher quality material than typical bank run or natural sands used in construction. Currently, an estimated 28% of discarded foundry sand is reused, primarily in construction-related applications, while the remaining sand is disposed of in landfills (American Foundry Society 2007). Recycling of foundry sand can save energy, reduce the need to mine virgin materials, and may reduce costs for both producers and end users. Use of foundry sand as a fine aggregate in construction applications offers project managers the ability to enhance green sustainable construction by reducing their carbon footprint, while also qualifying for LEED credits. The U. S. Environmental Protection Agency (EPA) recently estimated that at the current recycling level 20,000 tons of CO₂ emissions are prevented while 200 billion BTUs of energy are saved (US EPA 2008). Support for increased reuse of foundry sand has brought together the U.S. EPA, the Federal Highway Administration, the U. S. Department of Agriculture, the Recycled Materials Resource Center (RMRC), state environmental agencies, the foundry industry and end users to develop the tools and resources needed to increase foundry sand recycling to 50% by 2015. This paper provides a comprehensive overview of the engineering and construction properties of foundry sand for use in Portland cement concrete, hot mix asphalt, road subbase layers, embankments, and flowable fill. Recent studies addressing environmental concerns of using foundry sand as a construction material are reviewed. With the goal of advancing use of foundry sand in construction application, references to resources and tools, such as web-based training and a foundry locator map module, are made available.

The use of shredded scrap tires (also referred to as tire-derived aggregate: TDA) in civil engineering applications has three major advantages: shredded tires (TDA) have engineering properties that are beneficial to civil engineers; TDA is often the lowest cost material that can provide the engineering properties sought and TDA can use large-scale numbers of scrap tires. The use of TDA could provide a much-needed, large-scale market where few other viable end uses for scrap tires exist. Tire-derived aggregate can be used in a wide range of highway uses and is currently one of the three major markets for scrap tires. In 2007, an estimated 561.6 thousand tons of TDA was used in this market; about 12 percent of the total number of tires that went to an end use market (RMA, 2009). Furthermore, tire shreds have been shown to have a negligible impact on groundwater quality. This paper will present the special properties of tire shreds that drive engineering applications. Examples will be given of projects where tire shreds were used as lightweight fill for highway embankment construction, bridge abutment backfill and as a thermal insulation to limit frost penetration beneath roads. The guidelines to limit heating and water quality effects of tire shreds will be discussed. From the information presented below, it will be clear that the use of TDA can benefit civil engineering projects and can play a key role in putting this nation's scrap tires to a productive reuse.

National, state/provincial and municipal legislation regulating stormwater runoff in the United States and Canada has provided increased incentives for using permeable pavements. In addition, regulatory frameworks for implementation of sustainable design have embraced permeable pavement solutions. These regulations are often called low impact development (LID) or sustainable urban drainage systems (SUDS). A logical and technically sound design process using design software can support design professionals and help permeable pavement achieve full potential in North America. In 2008, the Interlocking Concrete Pavement Institute (ICPI) introduced a non-proprietary software program called Permeable Design Pro that integrates hydrological and structural design solutions for permeable interlocking concrete pavement (PICP). The hydrological analysis determines if the volume of water from user-selected rainfall events can be stored and released by the pavement structure. User defined parameters determine how much water infiltrates the subgrade, infiltrates into the soil subgrade, enters pipe subdrains or flows from the pavement surface. The structural capacity of PICP is determined using the American Association of State Highway and Transportation Officials (AASHTO) 1993 structural design equations for base/subbase thickness to support vehicular traffic. This paper describes the development of the structural and hydrological design methodology with an example of its use.

Rises in construction and asphalt binder costs, as well as the growing pressures on landfills, have contributed to the increased use of Recycled Asphalt Shingles (RAS) in Hot Mixed Asphalt (HMA) Pavement Mixtures. Initial incorporation of Manufacturers Waste Scrap Shingles (MWSS) into HMA pavements yielded encouraging results and prompted waste management organizations, industry and government to investigate incorporation of Tear-Off Scrap Shingles (TOSS). As of 2009, the Minnesota Department of Transportation (Mn/DOT) standard specifications only allowed a 5% MWSS replacement for the allowable Recycled Asphalt Pavement (RAP) and TOSS was permitted, only with, "prior approval from the engineer". This need to get approval greatly reduced the willingness of local entities to use TOSS. Furthermore, a high-profile, pre-mature, and expensive, pavement failure prompted many to re-evaluate the benefits of using RAS in HMA pavement mixtures. A multi-agency research effort between Mn/DOT and the Minnesota Pollution Control Agency (MPCA) was initiated with the goal of making a recommendation on a comprehensive RAS specification, including the option of using TOSS that would allow agencies to realize the economic and environmental benefits without compromising pavement performance or durability. The research study (1) incorporated both controlled laboratory experiments and evaluations of in service pavements. Several producers submitted their ground RAS samples to the Mn/Dot laboratory for inclusion in the study. These RAS samples were tested for gradation, and deleterious materials (DM) content; these results were later used to assist in the development of an initial specification. In addition, the RAS samples were tested for the performance grade (PG) of the asphalt binder. Laboratory-produced HMA mixtures incorporating: Tear-Off Scrap Shingles (TOSS), or Manufacturer Waste Scrap Shingles (MWSS), and/or Recycled Asphalt Pavement (RAP) were tested for both asphalt binder PG grades and mixture dynamic modulus. It was concluded that the shingle properties, especially the fineness of the grind, and shingle type and the amount of recycled materials used in the HMA mixture had an impact on pavement performance. The knowledge gained from the collaborative research effort helped decision makers make an informed decision on a 2010 comprehensive RAP/RAS specification, which now allows the use of TOSS as a substitute for the total RAP content of the mix.

In 2006 the City of Saskatoon recognized that the large amounts of asphalt and concrete rubble materials stockpiled in its yards must be addressed. After experimenting with the material as a replacement backfill material with City forces, the City determined that improved engineering specifications and structural design processes needed to be implemented to facilitate the standard use of the recycled aggregates. In 2009, the City of Saskatoon developed the Green Streets Program to pilot the use of advanced mechanistic engineering and state of the art impact crushing of rubble materials for roadway construction. For the program to be considered successful value added processing, mechanistic-climatic characterization and sustainable holistic life cycle analysis had to be considered. Based on the findings of the City of Saskatoon Green Streets Program, the City is now producing five types of high value specified crushed concrete materials, and three types of specified asphalt aggregate materials. These materials are being used as subbase, base course, drainage rock, stress dissipation layers and structural black base. From a mechanistic engineering characterization perspective, this research shows the crushed concrete and crushed asphalt aggregates are technically superior to conventional locally available aggregates. The City of Saskatoon Green Streets Program identified many benefits achieved through the use of recycled materials in road construction on a technical, social, environmental and economic basis. Residents are provided a roadway with superior structural performance and waste rubble generated from aging city infrastructure is diverted from landfills. In addition, the cost savings generated by the Green Streets Project was determined to be approximately 55 percent through the structurally equivalent substitution of recycled aggregates for virgin sourced aggregates. To further address the key aspects of road infrastructure sustainability the quantification of the energy used to rehabilitate roads and carbon generation during roadway rehabilitation will assist in quantifying the benefits of sustainable construction solutions. The future implementation of mechanistic based End Product Specifications will also ensure that the City will have a reliable engineering framework from which to employ innovative and sustainable road infrastructure solutions utilizing recycled road materials.

The use of recycled materials for roadway construction has received increased interest from transportation agencies in the past several years. One commonly overlooked recycled material is the use of post consumer recycled asphalt shingles (RAS) in hot mix asphalt (HMA). With the availability of post consumer recycled asphalt shingles (RAS) increasing in the United States, there is a growing interest in the application of post consumer RAS in HMA. More than 10 million tons of post consumer shingles are being placed in landfills annually. These shingles contain and estimated 20 to 30 percent asphalt. The research presented in this paper studies the effects of post consumer shingles on the performance of HMA and its compatibility with fractionated recycled asphalt pavement (FRAP), the sizing and subsequent proportioning of RAP for use in HMA. In the summer of 2009 a field demonstration project was conducted by the Illinois State Toll Authority on Interstate Highway I-90. Eight mix designs containing five percent RAS and varying percentages of FRAP were developed and placed in three different areas of the pavement structure: the base course, the shoulder binder course, and the shoulder surface course. The field demonstration included five experimental sections and three control sections. Production and laboratory samples of the mixes were obtained for dynamic modulus testing. Master curves for each of the mixes were constructed and analyzed for material response at different temperatures and loading conditions. These material characteristic results indicate the experimental mixes contain an increased resistance to permanent deformation without a significant decrease in low temperature cracking susceptibility.

Permeable interlocking concrete pavements (PICP) combine stormwater infiltration, detention and a riding surface for vehicles into one location. These pavements rely on an open-graded crushed stone base for storage, infiltration and vehicular support. Much research has been conducted on the hydrologic and water quality aspects. State and municipal best management practices (BMP) and low impact development (LID) manuals have incorporated design guidelines developed from university research, industry guidelines and experience by various agencies, project owners, civil engineers and contractors. This paper integrates hydrological and structural design for PICP for potential use in the emerging American Society of Civil Engineers (ASCE) guidelines for permeable pavement. Hydrological analysis determines if the volume of water from user-selected rainfall events can be stored and released by the pavement base. Designer-selected parameters determine how much water infiltrates the soil subgrade and/or is carried away by subdrains. Structural capacity for vehicular loads is determined using PICP industry design charts or the American Association of State Highway and Transportation Officials (AASHTO) 1993 structural design method. This paper includes design examples using these methodologies with an example using design software. The paper includes input design considerations as well as outputs for stormwater drainage and pavement design. In addition, recent experience is summarized on surface cleaning and surface repair.

Sustainable pavement designs call for energy-efficient and durable materials that lead to long-lasting, safe and economical highways. This paper presents the results of the laboratory study on rutting susceptibility of the Hot-Mix Asphalt (HMA) mixes used in the North East region of the US. A total of 40 different HMA combinations were included in this study. The HMA mixes were prepared with five different Polymer Modified Binders (PMB): 70-28, 76-22, 64-28, 64-28PPA, and 58-34. These binders were combined with four Reclaimed Asphalt Pavement (RAP) sources in two different ways. In the control mixes, the RAP was first burned to remove the RAP binder and only the RAP aggregate was added to the base batch of a virgin binder and aggregate. In the second set of mixes, the RAP was added at 10 percent of the total mix weight. The RAP sources differed in the mineralogical origin of their aggregates. Each of the four RAPs consisted primarily of one of the following minerals: granite, basalt, schist, and limestone. All 40 mixes were compacted according to the mix design with 12.5 mm Nominal Maximum Aggregate Size (NMAS) using the one virgin aggregate source. In order to evaluate rutting susceptibility, mixes were tested in the Asphalt Pavement Analyzer (APA) at the high PG grade temperature of the corresponding binder with the rate of 60 cycles per minute. This paper outlines the methodology, presents experimental data and includes statistical analysis of the APA results.

This paper encompasses the evaluation and research of high-volume fly ash (HVFA) concrete. The primary objective of this study was to examine increased levels of cement replacement with Class F fly ash for concrete used in Colorado highways. Fly ash is a byproduct of the combustion of pulverized coal in electric power generating plants. The benefits of using fly ash in concrete include increased compressive strength and durability, and reduced sulfate attack, shrinkage, and cost. Four HVFA concrete mixtures with 50%, 60%, 70%, and 80% Class F fly ash were designed and tested for compressive and tensile strength and permeability. Compressive strength tests were conducted at 3, 7, 28, and 56 days of age. The permeability and tensile strength of the mixtures were measured at 28 and 56 days of age. The Colorado Department of Transportation (CDOT) Class P mixture was used as the base mixture for this study. This class of concrete is specific for concrete pavements used for Colorado streets and highways. Required field compressive strength of Class P concrete is 29 MPa (4200 psi) at 28 days; a minimum cementitious content of 392kg/m³ (660 lbs/cy); air content ranges between 4–8% and a maximum water/cementitious material ratio of 0.44 is specified by the CDOT. The results of this study provide sufficient evidence that increased amounts of fly ash (above typical limits) can be incorporated into concrete mixtures for streets and highways.

Sustainable concrete described as concrete incorporating by-products or waste materials is not a new topic. In fact, published research on the use of fly ash, as a replacement for cement in concrete dates back to the 1930s. Additionally, a considerable amount of research supports the use of sustainable concrete in pavements and/or structural components with beneficial results pertaining to reduction in CO₂ emissions, reduction in cost, and achievements in strength and durability. Despite positive research, achieving a more permanent use of sustainable concrete in street and highway projects may require the advocacy for increased utilization of fly ash concrete. This paper argues that increased use of fly ash concrete can occur through continuing fly ash concrete research, motivating public policy efforts and, and furthering technology transfer. Additionally these strategies could contribute to a more committed application of sustainable concrete in street and highway projects.

Concrete is the most widely used man-made material, and the manufacture of Portland cement — the active ingredient of concrete - accounts for 6 to 8 percent worldwide of all anthropogenic emissions of carbon dioxide, a leading greenhouse gas involved in global warming. Globally, nearly 2.77 billion metric tons (t) (3.05 billion st) of portland and hydraulic cement was produced in 2007. The concrete construction sector has a responsibility to take immediate action to reduce its environmental impacts, including the generation reduction of CO2. This responsibility also brings the opportunity to develop innovative technologies, including use of materials from Coal Combustion Products (CCP's). These newly developed activated fly ash based products leave virtually no carbon footprint. Updated cementitious binder technology eliminates approximately 0.9 t (1 st) of CO₂ emitted into the atmosphere per ton of portland cement produced. These cements have been engineered for use in fast track concrete repairs and construction, conventional paving, walls and concrete block masonry, new construction and repair projects. Activated pozzolanic material cements and resulting products are comprised of up to 95 percent green sustainable industrial waste stream materials, primarily fly ash. They are manufactured via a low energy, powder blending process. Key to green cement development was creating a material matrix that has a very dense crystal structure. This green cement technology possesses excellent performance and durability characteristics, including high early strengths and 28-day strengths over 70 MPa (10,000 psi). Moreover, they can be placed effectively with ambient temperatures ranging from –1°C to 49°C (30°F to 120°F).

In one of the largest cities in the world, the concern to prevent and reverse the environmental damage caused by a disorganized and uncontrolled planning process, becomes a primary focus on the development of a city. The specific options that concrete gives us in terms of sustainability according to their physical and mechanical characteristics enabled the Government of Mexico City to create a sustainable solution for one of the largest thoroughfares of this city, the Inner Circuit. Sustainable benefits were reported in three areas, the social, economic and environmental improvement over other materials performance in durability, safety, energy conservation, heat island effect and others. The repaving project of Inner Circuit of Mexico City, not only involves the incorporation of a sustainable material in the pavement but all works carried out on alternate result of the project, such as empowerment of green areas, recreational areas along the 42 kilometers that make up the circuit, the use of sustainable alternatives and innovative recycled materials and waste. Now, the Inner Circuit in Mexico City is an example of sustainable project on highways and streets.

Thin Whitetopping (TWT) is the process of rehabilitating distressed asphalt concrete (AC) pavements using a concrete overlay. Thin Whitetopping has the potential to become a low maintenance, green treatment for the AC pavements needing rehabilitation in the urban area because of unique advantages offered by concrete. This study was done to develop a design procedure for the AC pavements to be overlaid with TWT using finite element (FE) analysis. The FE analysis was performed with SolidWorks, a 3-D FE software program for different TWT thickness, existing AC layer thickness and modulus, bonding condition between TWT and existing AC layer, and temperature differentials. Each model was built as a three-layer pavement system- concrete (TWT), asphalt layer and subgrade soil. The traffic load was modeled as a constant pressure with a rectangular area applied at the surface and with intensity equal to the tire inflation pressure of 100 psi. The expected lives of TWT overlays were estimated using the equations developed by the Portland Cement Association (PCA). The greener aspects of such a treatment were outlined.

Soils in the eastern part of Nigeria are known for high erosivity and collapse, and as a result, roads and infrastructural developments of the area have been a difficult and expensive venture. The constructed road infrastructures are found not to be durable due to weakening effect of subgrade by erosion during rain. There have been serious investigations on ways of improving these soils to enhance their performance in pavement construction but a number of stabilizers used such as cement and lime have resulted in high cost of construction. This problem forms the basis of an extensive investigations currently being conducted on economic and sustainable methods of improving the engineering qualities of the soil and thus enhance their performance under pavement traffic load. This paper presents results of on-going laboratory studies on the effects of cement kiln dust, a waste product from cement manufacture, in stabilizing the problem soil of Amatutu/Agulu in Anambra State, Eastern Nigeria, and thus finds an economic use of the waste in civil engineering construction in Nigeria. The results of engineering properties of the soil tested i.e. Atterberg Limits, Dry-Density, California Bearing Ratio (CBR), and Unconfined Compression Strength (UCS), when CKD was added at varying percentages showed an improvement over the "as-is" soil engineering properties, thus giving hope of improved pavement performance in the area with CKD. Also, the result showed that CKD, a waste material from cement manufacture, can be profitably utilized in civil engineering construction and therefore contribute to environment sustainability and green development in Nigeria.

Transportation is an essential component of a sustainable society, and its benefits and costs are well studied at the project level (FHWA 2001; Green Highways Partnership 2010). However, while methodologies for assessing environmental impacts are well developed, commensurate tools for assessing how transportation investments contribute to a sustainable society and what the mechanisms are for adjusting transportation programs to support a sustainable society are lacking. Under the current construct, transportation agencies avoid impacts but find it difficult to quantify benefits and align transportation programs with the greater needs of a sustainable society. The New York State Department of Transportation's (NYSDOT's) GreenLITES (Green Leadership In Transportation and Environmental Sustainability) program is a tool to advance the Department's efforts to better align sustainability efforts in planning, design, construction, and maintenance operations with long term needs. Though the Department has been incorporating sustainable elements into its transportation projects for years, GreenLITES promotes increased awareness and best practices across program areas to enhance sustainability. GreenLITES also gives the Department a way to measure our performance, recognize best practices, and identify needed partnerships. GreenLITES was initially designed to assess capital project environmental sustainability elements. However, as GreenLITES was put into use, its potential to address transportation investments across a range of program areas became apparent, and a more holistic approach to the "triple bottom line" of economy, society, and environment has been adopted. As a result, the GreenLITES program expanded to include a growing collection of tools (rating systems, spreadsheets, and other metrics) to assess projects, plans, operations and maintenance programs, and regional programs. This paper describes NYSDOT's GreenLITES program evolution from its environmentally based beginnings to a more comprehensive approach in support of a more sustainable society. The paper covers program vision, goals, benefits, management, and evolving next steps.

This paper describes a green highway construction rating system named Building Environmentally and Economically Sustainable Transportation Infrastructure-Highways (BE²ST in-Highways). BE²ST in-Highways employs life cycle analysis techniques to provide a quantitative assessment of the impacts associated with a highway construction project. Energy and water consumption, greenhouse gas emissions, service life, and life cycle cost are evaluated in a quantitative framework that can be used to compare alternative construction strategies from a holistic perspective. The methodology is grounded in quantitative metrics rather than an arbitrary point system so that a transparent linkage exists between the project rating and the sustainable practices employed in design and construction. This transparency reduces the potential for `gaming' of the rating system. Application of the BE²ST in-Highways system to a project in Wisconsin is described. Results of the application indicate that using recycled materials in a pavement can result in reductions in global warming potential (32%), energy consumption (28%), water consumption (29%), and hazardous waste generation (25%) as compared to the reference design using conventional materials, while also extending the service life of the pavement. In addition, using recycled materials in a pavement can result in a life cycle cost savings of 23%. Because of this environmental and economical outperformance of the alternative design using recycled materials compared to the reference design using conventional materials, the maximum total credit (i.e., 12 points) is granted to the project.

In January 2010, the Illinois Department of Transportation, the American Consulting Engineers Council — Illinois Chapter, and the Illinois Road and Transportation Builders Association released a sustainability guide and rating system entitled I-LAST, Illinois - Livable and Sustainable Transportation. The document was developed by volunteers from these organizations over a two-year period. This paper reviews the reasons for undertaking this project, the contents of the resulting document, and the decisions made during its development.