Green Streets, Highways, and Development 2013: Advancing the Practice

Recent emphasis on sustainability in the field of transportation has resulted in newly developed sustainability rating systems. However, there is little guidance or industry-wide experience to instruct practitioners on how to integrate sustainability throughout the project lifecycle. The Office of Federal Lands Highway (FLH) of the Federal Highway Administration (FHWA) has been evaluating the use of sustainable practices during road design and construction by utilizing rating tools such as Greenroads and INVEST. Based on these evaluations, FLH has identified best management practices to integrate sustainability in road design and construction. This paper first presents the results of evaluations, then identifies the best management practices, and finally provides an integrated approach for designing and building sustainable roads. The approach is applicable to the project development phases of the project lifecycle, which include project planning, design, and construction. The approach presented in this paper emphasizes interdisciplinary coordination, maintaining accountability of sustainability throughout project development and appropriately utilizing resources. This paper provides a six-step approach for practitioners to integrate sustainability into the planning, design, and construction of roadway projects. The six steps in this approach are (1) Develop a Sustainability Vision, (2) Identify Project Context, (3) Define Sustainability Goals, (4) Identify Sustainable Solutions, (5) Assess and Select Sustainable Solutions, and (6) Incorporate Solutions.

The Morgan Street Bridge project is a demonstration of the City of Rockford's commitment to sustainability and the betterment of the community for all of its citizens. From a transportation perspective, replacing an aging bridge results in safety benefits that include a sturdier structure and the opportunity to improve traffic flow. These were certainly major considerations back in 2000 when the decision was made to begin planning for the replacement of the Morgan Street Bridge in Rockford, IL. By the time ground broke for construction of the new bridge in the summer of 2012, the list of benefits grew substantially. The bridge project had become a catalyst to unify the community through the revitalization of an impoverished area of town and a committed effort to identify and implement context-sensitive and sustainable solutions.

Permeable pavements have been gaining popularity throughout North America. Permeable pavements typically consist of pervious concrete, porous asphalt, or permeable interlocking concrete block paving units over an open grade base/subbase layer(s). Permeable pavements are designed to infiltrate stormwater, reduce peak flows, filter and clean contaminants in the water stream, and promote groundwater recharge. They have become an integral part of low-impact design and best management practices for stormwater management. To be effective, permeable pavements must be designed to provide sufficient structural capacity to accommodate the anticipated vehicle loadings and deal with stormwater flowing into and out of the permeable pavement. While there have been many well designed and constructed permeable pavements, this is a relatively new technology and there have been some "issues" with their performance. This paper describes some of the basics of best practices, design, construction, and maintenance considerations for permeable pavement design and construction and focuses on best practices of permeable pavement design and construction in North America.

Advancement of the practice of building sustainable highway networks can be furthered by effective use of historical records. To this end, this paper presents analysis of a historical record of approved asphalt mixture designs maintained by the Mississippi Department of Transportation. Distributions of mixture properties are analyzed and discussed, and properties of the reclaimed asphalt pavement (RAP) materials in the dataset are compared with total asphalt mixture properties. The data highlights the materials diversity that occurs within the jurisdiction of an agency. Benefits and applications of such an analysis of historical records are discussed. Applications for the data include re-using RAP in plant mixed asphalt, in-place recycling, and educating the next generation of pavement materials engineers. The data collection and analysis techniques are straightforward, easy to perform, and low cost, while the potential benefits to an agency are high.

Pavements absorb a large amount of solar radiation. High pavement temperatures in warm climates cause problems such as rutting and accelerated aging of the mix, the urban heat island effect, and deterioration of air quality. This paper discusses, with models and experimental results, the concept of using an insulation layer, such as a geotextile, and aggregates with higher reflectivity in chip seals to reduce the conduction of heat through an asphalt pavement and increase the reflectivity of the surface. Reductions of temperature in the range of 8-10 °C were noted at the surface and 75 mm below the surface with the use of a 2.4 mm thick Petromat geotextile with chip seal. The study showed that a significant improvement in temperature reduction can be achieved with the use of a thicker insulation layer and/or an insulation of lower conductivity.

Warm mix asphalt (WMA) technology is steadily gaining popularity due to the environmental, energy, and cost savings it offers as a sustainable alternative to conventional hot mix asphalt (HMA). However, adoption of WMA for commercial and military airfield pavements has been slow due to lack of documented good performance on airfields and concerns about potential rutting problems. This paper presents testing results for 11 WMA technologies, compared with traditional HMA. One unmodified base binder and one aggregate gradation were utilized throughout. Both laboratory full-scale plant-produced materials are tested. Binder performance grade (PG) data and Asphalt Pavement Analyzer (APA) mixture rutting data are presented. Relationships between laboratory and plant produced binder data and APA rutting are explored. The overall conclusion is that WMA is a viable alternative to HMA to improve the sustainability of airfield pavements.

Performance-based specifications (PBS) are emerging as an alternative to method specifications for roadway maintenance. Under PBS, the highway agency specifies measurable performance standards that the maintenance contractor is required to meet throughout the contract period. PBS for roadside maintenance are still evolving. This paper describes the development and field trials of PBS for roadside maintenance, including performance standards, a level of service (LOS) method for assessing compliance with these standards, and pay adjustment formulas. Twelve roadside asset types and maintenance activities are considered in these PBS, including safety elements (attenuators, guard rails, and chain link fences); drainage elements (ditches and front slopes, culverts and cross-drain pipes, and drain inlets); cleanliness elements (removal of litter, debris, and graffiti); and vegetation (roadside grass, landscaped areas, trees, shrubs, and vines). The developed PBS were tested on five highway corridors in Texas.

This paper reviews technical development of the emerging ASCE standard for permeable interlocking concrete pavement or PICP. The draft standard notes key design elements, which include high-strength, impermeable concrete units for a pavement surface that meet ASTM or CSA standards. When installed, the joints between units are filled with permeable aggregate. The units are placed over an open-graded aggregate bedding course that rests on an open-graded aggregate base and subbase for water storage and structural support. While common to all permeable pavements, the document provides a design flow chart for structural and hydrologic design and outlines three commonly used infiltration approaches determined by site and subgrade conditions and designs for sloped subgrades. The draft standard addresses structural design for supporting traffic by modifying conventional flexible pavement design methodology from the American Association of State Highway and Transportation Officials. The draft resolves a key design consideration common to all three permeable pavements: the dichotomy between not compacting the soil subgrade for infiltration and compacting for enhanced structural support especially in saturated conditions. Besides guide construction specifications, construction and maintenance guidelines are provided via checklists. A key tool for assessing surface infiltration and subsequent vacuum cleaning is adoption of an ASTM surface infiltration test for pervious concrete, which has been successfully used for porous asphalt and PICP.

A number of developments have occurred recently to improve asphalt's sustainability. During this time, the asphalt industry has increased the number of mix options arguably more than any other time in history. This ever-increasing list of options emphasizes the need for performance testing as opposed to more traditional reliance largely on volumetric properties. A key area related to performance testing is comparing laboratory mixing and compaction to plant mixing and field compaction. Therefore, the primary objective of this paper was to assess differences between laboratory and field compaction for plant-mixed asphalt using wheel tracking. A total of 398 specimens were available for this assessment, some of which were field compacted cores from a single lift that was approximately 70 mm thick. Having field compacted cores from a single lift of suitable wheel tracking thickness was a key component of this paper. A secondary objective of this paper was to assess differences between laboratory and plant mixing using wheel tracking; a modest number of specimens were available for this purpose. This paper found no meaningful rut depth differences for laboratory and field compacted materials for one wheel tracker, but did find potentially meaningful differences for a second wheel tracker.

Degradation due to temperature fluctuation is the predominant deterioration mechanism affecting many asphalt and cementitious pavement systems. Reduced durability, in turn, limits the sustainability of a materials system: maintenance and replacement are almost always energy and resource intensive. As such, accurate quantification of the thermal properties of any given pavement material is necessary to determine durability and evaluate the effectiveness of novel technologies. Two somewhat inexpensive apparatuses have been developed for this purpose. The first, a Guarded Longitudinal Calorimeter (GLC), measures heat flow through a specimen sandwiched between standards of known thermal properties during either heating or cooling; from the measured heat flow data, many useful thermal properties (apparent thermal conductivity, etc.) can be obtained. The second device, a Solar Simulator, measures the temperature at different depths in multiple well-insulated specimens as they are heated or cooled by halogen lamps or cooled air blowers. The theory, construction, and operation of these devices will be detailed, and the results of analyzing pavement materials in each will be discussed.

The coefficient of thermal expansion (COTE) is an important concrete property that characterizes the dimensional change of concrete subjected to temperature change. In jointed concrete pavements (JCP), expansion joints are used to accommodate length changes due to temperature variations. However, for continuously reinforced concrete pavements (CRCP) with high COTE aggregates, there are no expansion joints to accommodate the length changes. In Texas some districts with high volumes of CRCP, such as Houston, Dallas, and Forth Worth, experience a high degree of transverse cracking, horizontal cracking, and punchouts due to the environmental loading in high COTE concrete CRCP. Very recently the Texas Department of Transportation (TxDOT) imposed a limit on COTE as an acceptance criterion for pavement concrete aggregates. Houston and Beaumont do not have low COTE aggregate sources in the vicinity, and to meet the current TxDOT requirement these two districts have to haul aggregates from long distances. This will not only increase the transportation cost but also limit the use of locally available good quality aggregates, which has high COTE. COTE of concrete can be reduced by blending high and low COTE aggregates. This research study used three high COTE aggregate sources from different strategic locations in Texas suggested by TxDOT; they were each blended with low COTE limestone aggregate at different replacement ratios. Results showed that concrete COTE can be reduced by blending low COTE aggregates with high COTE aggregates. The COTE of concrete decreases linearly with an increase in limestone replacement. These findings will help TxDOT use the local high COTE aggregate sources by blending with imported low COTE aggregates. Aggregate producers with high COTE aggregates can also determine the degree of replacement necessary for their aggregates to be accepted in a TxDOT CRCP paving projects.

Concern about the environmental impacts of highway runoff has led many regulatory agencies to require its treatment prior to discharge. An emerging technology for treating highway runoff is the permeable friction course (PFC). PFC consists of a layer of porous asphalt approximately 50 mm thick placed as an overlay on top of an existing conventional surface. The objective of this paper is to demonstrate the effectiveness of PFC on highways with curb and gutter systems. Data from two sites on an urban Texas highway are presented. Observed concentrations of pollutants were much lower in the runoff from the PFC than from the conventional asphalt. The reduction in total suspended solids concentration was about 92%. A comparison with the discharge quality observed from media filters is also included that indicates equal or better pollutant removal on PFC highways. A comparison of water quality from various pavement mixes and shoulder types demonstrates that PFC can be effective under many different conditions.

The focus of this project is the assessment of the potential for sorption to reduce the concentration of dissolved heavy metals in runoff.One difficulty in evaluating adsorption in multi-component systems is to capture the impacts of background organic matter and other complexing ions on adsorption behavior. A compromise between using natural and synthetic storm water in this evaluation was therefore made by recognizing the importance of capturing the organic matter from natural storm water, but adding the flexibility of using laboratory chemicals to provide the inorganic constituents.To alleviate concerns associated with storing large volumes and aging of organic solutions, 1000 gallons of stormwater were collected and then concentrated by a factor of 150 using reverse osmosis. The stormwater was then freeze dried. The freeze-dried organic matter was reconstituted as needed at concentrations that mimic the initial total organic concentration of the stormwater when it was collected. A series of column experiments were then run using iron oxide, manganese oxide, Portland cement concrete, and crab shell waste as sorbents. Factors that were evaluated included organic matter concentration, competition between metal ion species (copper and zinc), pH, and ionic strength. The results of the column experiments indicate that iron oxide provides substantially better removal of dissolved metals than manganese. Portland cement concrete and crab shell waste were both found to be effective at controlling pH, which is the largest factor in determining dissolved metal removals. These experiments indicate that use of iron oxide augmented with either concrete or crab shell is potentially a cost-effective way to remove dissolved metals in highway runoff.

Low impact development (LID) is a design approach that utilizes stormwater control measures (SCMs) to maintain and restore the natural hydrologic regime of an urban watershed through infiltration, runoff treatment at the source, and minimization of impervious surfaces. This paired watershed study evaluated the impacts of LID SCMs on hydrology and water quality at a catchment scale. In February 2012, a pair of bioretention cell (BRC) bumpouts, two permeable pavement parking stalls, and a tree filter device were installed to treat residential street runoff in Wilmington, North Carolina. In the LID-retrofit catchment, SCMs treated 52% of the directly connected impervious area (DCIA) and 69% of the total drainage area for potential mitigation of peak discharge and runoff volume. For water quality improvement, 94% of the DCIA and 91% of the total drainage area was retrofitted. Underlying soils in the study area were Baymeade Urban and Leon Urban sands. Mean peak discharge significantly decreased 28% post-retrofit and lag times in the catchment remained unchanged, while mean runoff depth significantly decreased 52%. When compared with the control catchment, runoff depths in the LID-retrofit catchment were significantly less for storms with low hourly storm intensities (<2.7 mm/hr), but significantly greater for storms with high intensities (>7.4 mm/hr). Runoff thresholds in the LID-retrofit and control catchments were 5.2 mm and 3.5 mm, respectively. The LID runoff coefficient significantly decreased by 47% from 0.22 to 0.13 and is substantially less than other runoff coefficients reported for traditional residential development. Post-retrofit concentrations of TKN, TP, TSS, Cu, Pb, and Zn significantly decreased by 62%, 38%, 82%, 55%, 89%, and 76%, respectively. Concentrations of NO_2,3-N and TAN did not change. Mass exports of TKN, TAN, O-PO₄^-3, TP, TSS, Cu, Pb, and Zn significantly decreased by 78%, 61%, 55%, 73%, 91%, 53%, 88%, and 77%, respectively. NO_2,3-N load decreased by 46%, although this was not significant. Most improvements in water quality were due to dramatic decreases of particulate and particulate-bound pollutant loads. This was attributed to first flush retention of runoff by the BRC and permeable pavement that treated 52% of the DCIA and treatment by the tree filter unit that serviced 42% of the DCIA. This study has shown that a limited number of LID SCMs installed within a medium density residential street right-of-way over sandy soils can mitigate some hydrologic and water quality impacts of existing development.

Municipalities in Southern California are facing an increasing amount of complexity in Municipal Separate Storm Sewer Systems (MS4) permits. Two of the more trying requirements for roadway projects that have been incorporated into permits in the region are hydromodification management (HM) and low-impact development (LID). These are being implemented as specific measurable requirements in permits and create significant challenges for municipalities. This paper analyzes the challenges that these requirements present for linear roadway projects and details the application of a stormwater model and technical feasibility analysis to identify cost-effective solutions.

Some insight into the benefits of regularly and frequently maintaining traffic signal timing within and across jurisdictional boundaries is provided. The rapidly growing Cranberry Township located at the crossroad of two interstate highways (Pennsylvania Turnpike [I-76] and I-79) in the state of Pennsylvania, 20 miles north of Pittsburgh is used as a case study. Environmental and economic costs due to the absence of monitoring and updating traffic signal timing are estimated. While traffic signal timing optimization and coordination is a cost effective strategy to reduce travel time and its consequential air emissions along corridors, implementing such timing plans is only effective at and around the time of implementation, while travel demand remains constant. As times passes, with the fluctuation of vehicular demands, especially in rapidly developing areas, timing plans need to be monitored and modified. In Cranberry Township such developments and travel demand fluctuations result in significant increase in costs of travel (time and fuel) and external environmental costs. Estimates show that timing plans that were at their optimal level at the time of implementation, if left unmodified, result in an 18% increase in the cost of fuel, a 13% increase in the cost of travel time, and an 11% increase in the external environmental costs in less than two years.

Construction activities and numbers of related work zones on urban freeways have grown significantly. The most problematic work zones occur on roads that are already fully loaded, and impacts of work zones on mobility and fuel efficiency make success of the traffic control plan vital. Full freeway closures are sometimes implemented to expedite project completion and thereby reduce the cumulative impact of construction on travelers; however, full closure can cause significant freeway congestion. Congestion costs American drivers more than $100 billion each year in wasted fuel and lost time. Reducing work zone congestion can be an effective energy conservation technique that not only saves fuel but also saves traveler time. If a work zone plan includes freeway closure, an effective diversion plan that makes drivers aware of delays and available alternate routes can help minimize congestion. Construction on the SH-71/IH-35 interchange required complete closure of all IH-35 main lanes. IH-35 is an important business corridor, conveniently connecting four large Texas cities and facilitating trade between Mexico and the United States. A parallel route, the SH-130 toll road, was made free to travelers during those closures. The purpose of this paper is to investigate driver route-switching behavior during the IH-35 closure and how that behavior reduced fuel consumption and explored options for relieving delays on IH-35 during future closures. The findings indicate that changes in traffic volume on SH-130 during the closure were statistically significant, although usage of SH-130 was less than anticipated and there was significant queuing on IH-35 at the work zone. Analysis was based on integrating data from all available sources. Traffic conditions of a nonclosure weekend were compared with the closure weekends, and fuel consumption was estimated.

Many communities have committed to reducing their greenhouse gas (GHG) emissions. Fulfilling these commitments often includes inventorying emissions, developing a local action plan, setting reduction targets, and measuring progress from plan implementation. Using the Waterloo region as a case study, a comparative analysis of estimation methodologies for community transportation emissions was conducted.The transportation sector is often a large part of many local GHG emission profiles and can be difficult to effectively measure. Three commonly used methodologies were compared and evaluated, vehicle kilometers traveled (VKT), vehicle registration methodology, and retail fuel sales.The evaluation considered accuracy of data inputs and outputs, resources' required ability to replicate for future inventories, and the ability to reflect impacts from the implementation of local actions. It was concluded that the fuel sales method is the least arduous, is reasonably accurate to replicate, and is suitable for monitoring progress.Municipalities would benefit from obtaining fuel sales data within their jurisdictional boundaries to estimate local transportation emissions for their inventory as it will also better reflect progress from implementing their reduction initiatives. Vehicle registration data can further assist with estimating potential reductions from the proposed action plan.

Vehicular fuel consumption and emissions performance (CO₂ and CO) are examined experimentally within single-lane roundabouts with a slip lane under yield, stop, and free-flow exit control scenarios; these are compared with no slip lane using a gap acceptance-based performance experimental assessment SIDRA tool. For comparison with other types of traffic control, the same experimental roundabout is converted into a signal intersection and into an all-way stop-controlled intersection. With a free-flow slip lane exit type, overall average total roundabout fuel consumption was reduced by 26%, CO₂ emissions were reduced 27%, and CO emissions were reduced 17%, compared with an all-way stop-controlled intersection. As expected, results indicate that a roundabout with a free-flow slip lane exit type significantly reduces total average fuel consumption and pollutant emissions within a roundabout compared with all-way stop-controlled intersection.

Off-network characteristics such as land use, demographic, and socioeconomic characteristics and on-network characteristics are indicators of development and growth patterns in a study area. These factors not only have an effect on truck trips generated or truck operations in an area but also influence mobility and safety offered by a transportation network. However, the role of these off- and on-network characteristics on intracity trucks crashes has not been studied in the past. The key objectives of this research are 1) to investigate the relation between intracity truck crash occurrences and various independent variables (off- and on-network characteristics) and 2) to develop macro-level intracity truck crash estimation models. A geographic information systems (GIS) based methodology was adopted to identify intracity truck crash zones, capture spatial off-network characteristics data within 0.25-mile buffer for each selected zone, and develop intracity truck crash estimation models. The working of the methodology is illustrated using 2008 data for the city of Charlotte, North Carolina. Truck crash occurrences seem to be significantly affected by land-use characteristics such as institutional area, heavy commercial area, and 0.25 to 0.5 acre residential area. Planning and building well balanced neighborhoods and implementing improved design strategies and safety treatments in residential areas will help promote safety and enhance quality of life in these areas.

In recent years, the transportation planning sector has witnessed a steady growth in the design and implementation of policies and projects aimed at providing infrastructure not only for automobiles, but also for pedestrians and bicyclists. In the United States, multiple cities have implemented policies and design frameworks to encourage more pedestrian and bicyclist activity. Providing increased connectivity is commonly held to facilitate these modes of travel, but connectivity has a complex relationship with drivers' route choices. Because interactions with motor vehicles are a major factor in pedestrian or bicycle comfort levels, connectivity has a complex interaction with nonmotorized modes as well. This paper presents a methodology for quantifying these interactions, paying particular attention to impacts on the bicycle and pedestrian modes in addition to vehicular modes. The use of active transportation indices (ATIs) play a central role in this analysis, linking shifts in vehicular volume to suitability for nonmotorized travel. This methodology is tested on networks representing the southern part of the Austin, Texas metropolitan area, but the formulation is generic and readily transferable to other regions. Results of this application indicate that average path travel times between origins and destinations within the network and the link-congestion attributes like the volume-to-capacity ratio rise with reductions in connectivity and network-accessibility at both the South Austin regional (full-network) level and also at the local (intersection) levels where ATI indices are affected in addition to them. Additionally, improved vehicular networks have favorable effects on pedestrian and bicyclist activity, also shown in this study through the isolated attribute of traffic volumes.

Using the Public Transit Greenhouse Gas (GHG) Emissions Management Calculator (hereafter the Calculator), this paper presents a case study of transit bus GHG emissions using Atlanta, GA, data. The Calculator, developed by Georgia Tech researchers, is the first load-based life cycle emissions model for transit buses. The modal modeling approach of the Calculator estimates emissions as an indirect function of engine load, which in turn is a function of transit services parameters such as driving cycle (idling and speed-acceleration profile), road grade, and passenger loading. Direct emissions are calculated based on the scaled tractive power (STP) operating mode bins employed in the Motor Vehicle Emissions Simulator (MOVES) model, and life cycle emissions are calculated using the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The case study compares life cycle greenhouse gas emissions of five vehicle technologies, conventional compression ignition, parallel hybrid electric, series hybrid electric, battery electric, and fuel-cell electric, in combination with three fuel types, conventional diesel, compressed natural gas (CNG), and 20% biodiesel. The comparisons are carried out for two public transit route types, e.g. an urban transit route vs. an express bus route. The Atlanta case study showcases the practice-ready capabilities of the GHG emissions calculator in assessing the differences in technology and fuel performances under different operating conditions. The results illustrate that the decision as to which bus technology-fuel combination produces the least greenhouse gas emissions is a function of location and route characteristics. The Calculator will support transit agencies in evaluating bus technologies for GHG emissions within the context of local conditions.

Foam stabilized base (FSB) is a cold asphalt recycled mix, which uses 100% reclaimed asphalt pavement (RAP) or a combination of RAP and crushed concrete pavement with 2 to 2.5% of foamed asphalt binder. The production process involves injecting 1 to 2% water into hot asphalt binder in a patented foaming chamber to develop foams that are 10 to 15 times the original volume of the asphalt cement. In additional to its cost advantage, foam stabilized base is more environmentally friendly than traditional bitumen stabilizers due to a reduction in natural resources, energy consumption during production and construction, and emissions of greenhouse gases (GHG). The application of FSB could help asset owners to meet their sustainability objectives and comply with relative regulatory requirements. This paper presents a life cycle analysis (LCA) of GHG emissions from FSB production and construction. The analysis assesses the environmental impacts of FSB compared with other alternative designs over the entire life cycle of pavement assets, including site preparation, raw material extraction and transportation, installation and construction, operations and maintenance, and asset demolition. Based on the analysis of a set of design alternatives and project cases, it is shown that FSB could reduce GHG emissions by up to 69.5% from project construction. This presentation is useful for 1) those who wish to understand the FSB material, pavement design, and construction; 2) designers and contractors who want to benchmark their design and construction options; 3) state and local agencies, which are increasingly mandated to improve their environmentally friendly engineering practices; and 4) researchers who wish to identify ways of improving construction designs and processes that reduce long-term GHG emissions.

This paper describes an approach to estimate life cycle costs and greenhouse gas emissions for residential brownfield and greenfield developments. The approach has been implemented in a spreadsheet estimation model that can be used to estimate the comparative life cycle costs and greenhouse gas emissions of major elements of residential brownfield redevelopments. The spreadsheet is available for download at http://www.cmu.edu/steinbrenner/brownfields/index.html. The estimation model includes default values and ranges based on a sample of U.S. residential brownfield and greenfield developments and other literature sources. Model users can enter information about their own developments and compare life cycle costs and emissions with the sample for individual characteristics. Five major characteristics are included for the life cycle assessment of brownfields compared with greenfields, including brownfield remediation, residential building construction, infrastructure costs, residential building utilities and maintenance, and resident travel. Based upon the sample of brownfield and greenfield developments included, the brownfield developments tend to have lower average overall impacts due to lower travel costs associated with infill development closer to city centers despite costs associated with remediation. These averages show that a brownfield development can save each person $150 annually, compared with a greenfield development. Greenhouse gas emissions savings are an average of $1,200 kgCO_2e per year per person. However, design decisions with respect to building type and density have large effects on overall development impacts for either brownfields or greenfields.

To prepare and protect societies, economies, and the environment from the potential impacts of climate change, adaptation is required. Specifically, transportation organizations throughout the country, including state Department of Transportation agencies and Metropolitan Planning Organizations (MPOs), should not only be reducing climate change impacts through mitigation but also supporting adaptation practices. This paper evaluates agencies' behavior in terms of their integration of adaptation practices with the transportation planning process. Eighteen MPOs within the Mid-Atlantic region are surveyed based on a series of questions to assess the agency's progress in adaptation such as vulnerability assessments, infrastructure design/construction, and practices that support mitigation. The results are used to compare progress across jurisdictions and identify areas for improvement. By providing guidance and methods for integrating adaptation practices, agencies can begin to protect and prepare transportation networks and facilities from the potential impacts of climate change.

Over the past 10 years, there has been a proliferation of methodologies and tools for rating the sustainability of transportation-related projects both in the United States and internationally. These tools provide the ability to evaluate the sustainability of alternative transportation and land development policies, plans, and projects. The tools therefore facilitate the process of making transportation and land development decisions that contribute to community sustainability in practice. This study reviews and assesses approaches to rating the sustainability of transportation systems and neighborhood developments by highlighting the state of the practice, outlining similarities and differences in the existing approaches, and determining which tools are more appropriate for various contexts and when it is valuable to combine different tools. The study also identifies opportunities for improving the existing practice.

As legislation continues to focus on greenhouse gas (GHG) and carbon dioxide (CO2) emissions and reductions, the terrestrial biome offers an attractive possibility to sequester carbon. Currently, the terrestrial pool is regarded as a CO2 sink, but scientists are unsure to what extent this trend will continue. Urbanization modifies the existing landscape, and little study has focused on the carbon (C) dynamics of specific urban land uses. In this research, the roadway environment, specifically the grassed right of way (ROW), was studied for carbon sequestration potential, an important ecosystem service. Transportation corridors exist worldwide, and the vegetated filter strip and swale (VFS/VS), two common stormwater control measures (SCMs), often constitute the grassed right of way adjacent to roadways. Carbon pools within roadway VFS/VS soils of North Carolina were specifically examined in this study. This research was conducted in two North Carolina physiographic regions: the Piedmont (characterized by clay-influenced soils) and the Coastal Plain (predominantly sandy soils). Approximately 700 soil samples were collected in VFS/VSs and wetland swales alongside major highways and analyzed for percent total soil C (% total C) and bulk density, which aided in obtaining the C density. Mean soil C densities were 2.55 ± 0.13 kg C m-2 (mean ± standard error, n=160, 0.2 m depth) in the Piedmont and 4.14 ± 0.15 kg C m-2 (n=160, 0.2 m depth) in Coastal Plain highway VFS/VSs. Because grasslands were reported to have similar carbon density values, they could be used as a surrogate land use for roadway VFS/VSs if no specific roadside data were available. Using a 37-year soil chronosequence, the carbon sequestration rate using a simple linear regression within Piedmont VFS/VSs was calculated at 0.053 kg C m-2 yr-1. Utilizing segmented linear regression models, the sequestration rate was calculated to be 0.155 kg C m-2 yr-1 for 15 years and 0.099 kg C m-2 yr-1 for the remaining 21.5 years. The roadside grass sequestration rate assumed by the Federal Highway Administration Carbon Sequestration Pilot Program (0.17 kg C m-2 yr-1) overestimates carbon accumulation by a factor of 3 in the linear model, and by a factor of 1.1 to 1.7 with the segmented linear models. Carbon density did not differ between dry and wetland swales, although % total C was significantly greater in wetland swales. Because C density and % total C in swales were not well defined by age, it appeared more appropriate to assess wetland swales and dry swales using a range of carbon values, rather than a rate of carbon sequestration. The mean VS C density was 3.05 ± 0.13 kg C m-2 (n=40, 0.2 m depth), while that for wetland swales was 5.04 ± 0.73 kg C m-2 (n=44, 0.2 m depth). If promoting C sequestration becomes a factor in ROW management, wetland swales would be more desirable than dry swales. While the VFS/VS sequestration rate is comparable to other grassed systems, the estimated 320-480 tons C per lane-mile expelled during roadway construction (Cass and Mukherjee 2011) is marginally offset through terrestrial sequestration in roadside VFS/VSs. Per kilometer of roadway constructed, Piedmont VFS/VSs would offset between 4% and 7% of C emitted during construction, depending on predictive model of C sequestration rate was used.

While transportation management plans (TMPs) are commonly developed to address work-zone safety and mobility needs of the traveling public during construction of highway projects, TMPs have yet to be firmly ingrained in the transit planning process. Coordinating and streamlining TMP strategies for both types of transportation projects is increasingly critical given the overlapping needs to maintain the operations of existing transportation systems during construction activities and the growing trend toward sustainability in transportation, including reducing traffic congestion and related air quality impacts. Beyond their traditional application, TMPs can serve as a means for accommodating the construction of transportation improvements while supporting the shift to more sustainable travel patterns once a project is in operation. This paper discusses the process for developing TMPs, while integrating strong sustainability principles. Topics that are addressed include 1) current national and regional TMP guidelines; 2) harnessing the use of the Internet, social media, and mobile-based applications as part of the overall approach to informing the traveling public of construction-related transportation impacts and alternative means of travel; and 3) balancing cost-effective TMP strategies with promoting alternative transportation modes during construction and after a project opens. Proposed recommendations include how to integrate sustainability elements into TMP strategies, how to leverage TMPs to engage the public in minimizing transportation impacts during construction, and how to approach developing TMPs, especially for transit projects.

This paper describes the Envision Sustainable Infrastructure Rating System, recently published by the Institute of Sustainable Infrastructure (ISI), and how the sustainable practices outlined by the rating system were applied to the East Rosedale Street Improvement project in Fort Worth, Texas. The design team at Freese and Nichols, Inc. (FNI) and the City of Fort Worth (City) used collaborative efforts to look at the project as a whole and evaluate how the project affects the community, the environment, and the economics of the area. While looking through the lenses of the Envision Sustainable Infrastructure Rating System, the engineering team at FNI, along with the team at the City, collaborated to develop a roadway that would improve pedestrian and vehicular safety and efficiency, incorporate the priorities of the local community, improve the local environment, and showcase the rich history of the region. The Envision Sustainable Infrastructure Rating System proved to be a beneficial guide for decision making by providing a framework for meeting sustainability goals. Through the use of the Envision Sustainable Infrastructure Rating System, FNI and the City designed the East Rosedale Street Roadway Improvement project in a manner that will be beneficial to the surrounding community now and for years to come.

Community livability is increasingly being examined and promoted as exemplary practice. This is due in part to the recognition of environmental, infrastructure, and land use variables contributing to sustainable, vibrant, and healthy places for people to live and work. The impact of freight on an urban community is significant, yet few efforts in the United States have been devoted to creating policies and practices that support livability while also recognizing the critical importance of freight transport to economic vitality. This paper summarizes an approach to understanding freight impacts on neighborhoods, defining what constitutes a freight-centric community, and identifying the livability priorities of residents. The methodology for the current study is presented, outlining stakeholder survey instruments and recruitment approaches. The livability priorities identified through the stakeholder surveys will be used to develop strategies or plans for improvement that include private sector-led operational changes, infrastructure improvements, public-sector policies, and placemaking. This research also tests the effectiveness of the term "livability" among stakeholder groups. While this work is based on Lamar Avenue, a high-volume, heavily congested freight corridor in Memphis, TN, this research will also benefit other freight-centric communities across the country.

District 11 of the California Department of Transportation (Caltrans) has been a leader in instituting sustainability practices to minimize transportation project impacts and enhance communities through which its facilities cross. Many of Caltrans' practices exceeded typical environmental mitigation commitments, but had not been gathered collectively into one set of sustainability practices or evaluated against industry standards. Parsons Brinckerhoff led an analysis for Caltrans District 11 to inventory sustainable practices implemented as part of the widening and realignment of State Route (SR) 76 in San Diego County. The team assessed the project against two leading national green infrastructure rating systems (FHWA and Greenroads) to help inventory the project's performance, developed a preliminary project "score," and gathered associated supporting documentation. The overall intent of this project was to help Caltrans raise the bar on its sustainability practices by identifying tangible steps that could be taken during both design and construction. This analysis found that the SR 76 would achieve most of the credits under the Environment and Water and Access and Equity categories, but not under Pavement Technologies. Assuming the Greenroads project requirements were met, the project would likely receive a Silver rating. Under the extended scorecard from the INVEST beta version rating system, the project would likely score a Gold rating. Enhancing pavement technology applications would help boost the rating under both systems. The analysis also confirmed that selection of a sustainability rating system would depend greatly on the needs and goals of an agency or project considering utilizing such a system.

The objective of this paper is to compute pedestrian and bicycle level of service (LOS) for 578 signalized interactions, examine spatial variations in the computed LOS, and compare them with pedestrian and bicycle crash locations. Data for Charlotte, North Carolina, were used to compute LOS; examine spatial variations in LOS and crashes; assess walkability, bikeability, and their effect on livability; and present the outcomes from the research. Data and analysis showed 37.17% of the selected signalized intersections have a pedestrian LOS of D or worse while 85.39% of the signalized intersections have a bicycle LOS of D or worse. The computed LOS (indicators of walkability and bikeability) for the selected signalized intersections was observed to vary by area type. As expected, the LOS was observed to decrease with an increase in the distance from the downtown/uptown area. While the LOS at the selected signalized intersections is good in downtown/uptown areas, it is relatively low at the selected signalized intersections in other areas. However, pedestrian and bicycle crashes tend to be relatively higher in number and distributed throughout the core urban area while they are lower in number in the suburban area. Integrating the computed pedestrian and bicycle LOS for the signalized intersections with activity levels or surrogate data such as land use, demographic, and socioeconomic data along with pedestrian and bicycle crash locations would help identify critical locations and assist in efficient allocation of resources based on the actual need.

Egypt is a country of contrast. Although it is the world's 30th largest country, with an area of approximately one million square kilometers, 97% of its population is concentrated along the Nile valley and delta, leaving approximately 96% of the country's area unpopulated. This has led to a concentration of business opportunities and services in and around major cities. Ultimately, migration has increased to these areas, limiting opportunities to develop other areas. The population is no longer able to grow and prosper within the old valley and needs to expand to more population centers in a way that is sustainable. This need has motivated efforts toward developing new cities that have the potential to house and accommodate sustainable communities. This paper is a brief description of a planning effort to identify areas suitable for sustainable alternatives in different parts of Egypt. It also presents the basis for a national transportation network to support these sustainable developments. As part of this planning effort, college students, researchers, and young professionals from a variety of disciplines are asked to submit their ideas for sustainable developments as part of a design competition. The competition, entitled "Sustainable Exit from the Valley," attracted more than 120 competitors and 42 different submissions. A panel of experts was used to evaluate and rank these proposed developments according to their sustainable economic potential and to develop a national transportation network that supports the proposed alternatives.

Traditional civil engineering practice methods are focused on publishing analog construction documents to support project delivery. Even with most internal processes being fully digital, most of the time and energy spent in engineering is consumed by the preparation of analog plans and specifications instead of the design itself. These documents then have to be reverse-engineered by digital-capable contractors for estimating, bidding, layout, and construction. A 2004 NIST report estimates that 40-60% of all engineering effort is consumed managing nointeroperable analog information. To produce a truly sustainable built environment, engineers need to be able to simulate multiple design options within traditional budgets. This will require eliminating the cost of producing traditional analog documents and delivering the digital design information directly to contractors and other stakeholders. This paper will focus on the need for, and recent prototyping of, new practice philosophies that support engineering management and project delivery in a fully digital world.