Context-sensitive solutions (CSS) is a theoretical and practical approach to transportation decision-making and design that takes into consideration the communities and lands through which streets, roads, and highways pass ("the context"). The term is closely related to but distinguishable from context-sensitive design in that it asserts that all decisions in transportation planning, project development, operations, and maintenance should be responsive to the context in which these activities occur, not simply the design process. CSS seeks to balance the need to move vehicles efficiently and safely with other desirable outcomes, including historic preservation, environmental sustainability, and the creation of vital public spaces. In transit projects, CSS generally refers to context sensitive planning, design, and development around transit stations, also known as transit-oriented development.
In contrast to long-standing practices in transportation design that place primary importance on moving traffic (vehicular throughput), the CSS process emphasizes that transportation facilities should fit their physical settings and preserve scenic, aesthetic, historic and environmental resources, while maintaining safety and mobility. For instance, if a state highway that passes through a downtown main street, applying CSS principles would entail creating a street where the movement of vehicles does not impede pedestrian activity and sidewalk commerce, rather than a street that is simply widened and straightened to increase speed, capacity and mobility for vehicles as a singular transportation objective. CSS therefore includes principles for context-sensitive decision-making that place a high value on community input and consensus, and more technical principles of context sensitive design.
When CSS principles are applied to transportation projects, the process involves a much broader range of disciplines than traditional transportation design methods, which rely exclusively on the judgment of traffic engineers. CSS is a collaborative, interdisciplinary approach that involves everyone with a significant stake in the project, such as the residents, businesses and local institutions that will be affected by an intervention or a failure to address the transportation implications of development such as congestion. Rather than approaching these stakeholders at the tail end of the design process in an attempt to gain approval, CSS emphasizes the need to incorporate their feedback from the very outset of the planning and design development processes and during all subsequent stages of construction, operations and maintenance.
The following list of qualities (developed at a 1998 conference for transportation planners called "Thinking Beyond the Pavement" [1] ) describe the core goals of the CSS process.
The CSS Product: Qualities of Excellence in Transportation Design
The "Qualities that Characterize Excellence in Transportation Design" – that is, of the physical end product of the CSS process – are:
- The project satisfies the purpose and needs as agreed to by a full range of stakeholders.
- This agreement is forged in the earliest phase of the project and amended as warranted as the project develops.
- The project is a safe facility for both the user and the community.
- The project is in harmony with the community, and it preserves environmental, scenic, aesthetic, historic, and natural resource values of the area, i.e., exhibits context sensitive design.
- The project exceeds the expectations of both designers and stakeholders and achieves a level of excellence in people's minds.
- The project involves efficient and effective use of the resources (time, budget, community) of all involved parties.
- The project is designed and built with minimal disruption to the community.
- The project is seen as having added lasting value to the community.
— As agreed upon by participants of the Thinking Beyond the Pavement Conference, 1998
This outline of the core steps in the CSS process was also developed at the "Thinking Beyond the Pavement" conference.
The CSS Process: Characteristics of the Process That Yield Excellence
"The Characteristics of the Process that will Yield Excellence in Transportation Design" are:
- Communication with all stakeholders is open, honest, early, and continuous.
- A multidisciplinary team is established early, with disciplines based on the needs of the specific project, and with the inclusion of the public.
- A full range of stakeholders is involved with transportation officials in the scoping phase (the period before design is begun when the scope of the project is agreed upon). The purposes of the project are clearly defined, and consensus on the scope is forged before proceeding.
- The highway development process is tailored to meet the circumstances. This process should examine multiple alternatives that will result in a consensus of approach methods.
- A commitment to the process from top agency officials and local leaders is secured.
- The public involvement process, which includes informal meetings, is tailored to the project.
- The landscape, the community, and valued resources are understood before engineering design is started. A full range of tools for communication about project alternatives is used (e.g., visualization).
— As agreed upon by participants of the Thinking Beyond the Pavement Conference, 1998
The initial guiding principles of CSS came out of the 1998 "Thinking Beyond the Pavement" conference as a means to describe and foster transportation projects that preserve and enhance the natural and built environments along with economic and social assets for neighborhoods they pass through. In 2003, the Federal Highway Administration announced that under one of its three Vital Few Objectives (Environmental Stewardship and Streamlining) they had a target goal of achieving CSS integration within all state Departments of Transportation by September 2007.
The American Association of State Highway and Transportation Organizations (AASHTO) is now (fall 2006) developing strategic goals and objectives for CSS which it describes as a "fundamental change in the way we do business." One principal element of this change is the way transportation planners and engineers address speed. Historically, the speed at which a vehicle can safely travel through the landscape has been regarded as a primary goal of transportation planning since it shortens travel time, saves money (time is money), and improves driver convenience. However, CSS recognizes that designing a facility for the maximum safe speed that is economically feasible can be detrimental to other community goals, and even to vehicle passengers themselves. CSS recognizes that the goal of transportation is social and economic exchange, which cannot occur at high speeds. Instead, CSS attempts to identify, through a community-based process, a "target speed" that promotes the optimum amount of social and economic exchange, with lowest environmental impacts, that is appropriate for the context. Thus, in cities, if higher vehicle speeds lower the amount of social exchange on a residential street (fewer friends, less street life etc.) then the street will be designed to encourage drivers to slow down so as not to reduce social exchange. In a similar manner, commercial streets will be designed to maximize commercial exchange and designed accordingly. In more rural areas where a primary goal is to move people and goods between human settlements, CSS can be compatible with much higher design speeds. Setting a target speed that is appropriate for the context, and then designing roads, highway and streets to make it difficult for drivers to exceed that target speed, is a central CSS principle and represents a fundamental shift in transportation planning practice.
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: CS1 maint: archived copy as title (link)A road is a thoroughfare for the conveyance of traffic that mostly has an improved surface for use by vehicles and pedestrians. Unlike streets, whose primary function is to serve as public spaces, the main function of roads is transportation.
Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl. It also advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood schools, complete streets, and mixed-use development with a range of housing choices. The term "smart growth" is particularly used in North America. In Europe and particularly the UK, the terms "compact city", "urban densification" or "urban intensification" have often been used to describe similar concepts, which have influenced government planning policies in the UK, the Netherlands and several other European countries.
Transportation engineering or transport engineering is the application of technology and scientific principles to the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, efficient, rapid, comfortable, convenient, economical, and environmentally compatible movement of people and goods transport.
Transportation planning is the process of defining future policies, goals, investments, and spatial planning designs to prepare for future needs to move people and goods to destinations. As practiced today, it is a collaborative process that incorporates the input of many stakeholders including various government agencies, the public and private businesses. Transportation planners apply a multi-modal and/or comprehensive approach to analyzing the wide range of alternatives and impacts on the transportation system to influence beneficial outcomes.
Highway engineering is a professional engineering discipline branching from the civil engineering subdiscipline of transportation engineering that involves the planning, design, construction, operation, and maintenance of roads, highways, streets, bridges, and tunnels to ensure safe and effective transportation of people and goods. Highway engineering became prominent towards the latter half of the 20th century after World War II. Standards of highway engineering are continuously being improved. Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, geometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance.
A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces, macadam, hoggin, cobblestone and granite setts were extensively used, but these have mostly been replaced by asphalt or concrete laid on a compacted base course. Asphalt mixtures have been used in pavement construction since the beginning of the 20th century and are of two types: metalled (hard-surfaced) and unmetalled roads. Metalled roadways are made to sustain vehicular load and so are usually made on frequently used roads. Unmetalled roads, also known as gravel roads or dirt roads, are rough and can sustain less weight. Road surfaces are frequently marked to guide traffic.
The American Public Transportation Association (APTA) is a nonprofit group of approximately 1,500 public and private sector member organizations that promotes and advocates for the interests of the public transportation industry in the United States.
A living street is a street designed with the interests of pedestrians and cyclists in mind by providing enriching and experiential spaces. Living streets also act as social spaces, allowing children to play and encouraging social interactions on a human scale, safely and legally. Living streets consider all pedestrians granting equal access to elders and those who are disabled. These roads are still available for use by motor vehicles; however, their design aims to reduce both the speed and dominance of motorized transport. The reduction of motor vehicle dominance creates more opportunities for public transportation.
Standards for Interstate Highways in the United States are defined by the American Association of State Highway and Transportation Officials (AASHTO) in the publication A Policy on Design Standards: Interstate System. For a certain highway to be considered an Interstate Highway, it must meet these construction requirements or obtain a waiver from the Federal Highway Administration.
Stopping sight distance is one of several types of sight distance used in road design. It is a near worst-case distance a vehicle driver needs to be able to see in order to have room to stop before colliding with something in the roadway, such as a pedestrian in a crosswalk, a stopped vehicle, or road debris. Insufficient sight distance can adversely affect the safety or operations of a roadway or intersection.
Complete streets is a transportation policy and design approach that requires streets to be planned, designed, operated and maintained to enable safe, convenient and comfortable travel and access for users of all ages and abilities regardless of their mode of transportation. Complete Streets allow for safe travel by those walking, cycling, driving automobiles, riding public transportation, or delivering goods.
The Green Highways Partnership (GHP) is a voluntary, public/private initiative that aims to encourage the building of green highways and to encourage environmental stewardship through integrated planning, regulatory flexibility, and market-based rewards.
The National Transportation Communications for Intelligent Transportation System Protocol (NTCIP) is a family of standards designed to achieve interoperability and interchangeability between computers and electronic traffic control equipment from different manufacturers.
The Transportation Expansion (T-REX) Project was a $1.67 billion project aimed at improving transportation options for commuters in the Denver metro area within the areas of Interstate 25 and 225, which was recognized as the 14th busiest intersection in the United States at the time. The T-REX effort widened major interstates to up to 5 mainline lanes in each direction and added 19 miles (31 km) of double-track light rail throughout the metropolitan area. The T-REX project finished 3.2% under its $1.67 billion budget and 22 months ahead of schedule in 2006.
The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage. Geometric design also affects an emerging fifth objective called "livability", which is defined as designing roads to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage.
Value sensitive design (VSD) is a theoretically grounded approach to the design of technology that accounts for human values in a principled and comprehensive manner. VSD originated within the field of information systems design and human-computer interaction to address design issues within the fields by emphasizing the ethical values of direct and indirect stakeholders. It was developed by Batya Friedman and Peter Kahn at the University of Washington starting in the late 1980s and early 1990s. Later, in 2019, Batya Friedman and David Hendry wrote a book on this topic called "Value Sensitive Design: Shaping Technology with Moral Imagination". Value Sensitive Design takes human values into account in a well-defined matter throughout the whole process. Designs are developed using an investigation consisting of three phases: conceptual, empirical and technological. These investigations are intended to be iterative, allowing the designer to modify the design continuously.
LEED for Neighborhood Development (LEED-ND), where "LEED" stands for Leadership in Energy and Environmental Design, is a United States-based rating system that integrates the principles of smart growth, urbanism, and green building into a national system for neighborhood design. LEED certification provides independent, third-party verification that a development's location and design meet accepted high levels of environmentally responsible, sustainable development.
Sustainable urbanism is both the study of cities and the practices to build them (urbanism), that focuses on promoting their long term viability by reducing consumption, waste and harmful impacts on people and place while enhancing the overall well-being of both people and place. Well-being includes the physical, ecological, economic, social, health and equity factors, among others, that comprise cities and their populations. In the context of contemporary urbanism, the term cities refers to several scales of human settlements from towns to cities, metropolises and mega-city regions that includes their peripheries / suburbs / exurbs. Sustainability is a key component to professional practice in urban planning and urban design along with its related disciplines landscape architecture, architecture, and civil and environmental engineering. Green urbanism and ecological urbanism are other common terms that are similar to sustainable urbanism, however they can be construed as focusing more on the natural environment and ecosystems and less on economic and social aspects. Also related to sustainable urbanism are the practices of land development called Sustainable development, which is the process of physically constructing sustainable buildings, as well as the practices of urban planning called smart growth or growth management, which denote the processes of planning, designing, and building urban settlements that are more sustainable than if they were not planned according to sustainability criteria and principles.
Urban freight distribution is the system and process by which goods are collected, transported, and distributed within urban environments. The urban freight system can include seaports, airports, manufacturing facilities, and warehouse/distribution centers that are connected by a network of railroads, rail yards, pipelines, highways, and roadways that enable goods to get to their destinations.
Pavement performance modeling or pavement deterioration modeling is the study of pavement deterioration throughout its life-cycle. The health of pavement is assessed using different performance indicators. Some of the most well-known performance indicators are Pavement Condition Index (PCI), International Roughness Index (IRI) and Present Serviceability Index (PSI), but sometimes a single distress such as rutting or the extent of crack is used. Among the most frequently used methods for pavement performance modeling are mechanistic models, mechanistic-empirical models, survival curves and Markov models. Recently, machine learning algorithms have been used for this purpose as well. Most studies on pavement performance modeling are based on IRI.