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177 CONCLUSIONS AND FUTURE RESEARCH CONCLUSIONS The primary outcome of this research effort is the development of a flexible framework to replace the existing functional classification scheme. This new framework will facilitate optimal geometric design solutions that take into account context, user needs, and functions. The Expanded FCS is designed to provide improved information to the designer so that balanced designs can be achieved through documented prioritization of roadway users and community needs. The new system is simple yet dynamic so that its straightforward application will be well received by all stakeholders. A remarkable amount of thought has already gone into possible alternatives to the FCS. This has yielded an extensive array of alternatives that address a range of perceived shortcomings. The recommended alternative Expanded FCS proposed by the research team takes advantage of the available forethought and provides a complete innovative framework that brings together context, road type, and user needs to establish multimodal design guidance and considerations to achieve context sensitive, enhanced solutions. The Expanded FCS is an advanced alternative that can fit a variety of situations and can be used for individual projects or adopted for jurisdiction use on all project development. Over the past decades, substantial efforts were undertaken to not only modernize current practices in highway design but to also address the publicâs concerns regarding potential adverse effects for the roadway designs developed. This new environment required that state DOTs reconsider how projects were developed and deliver designs that were in harmony with the surrounding context of the roadway. Major efforts were undertaken to shift the traditional project development approach to a more responsive process. This started with addressing concerns for the physical and cultural environments and continued with the encouragement of developing multidisciplinary design teams and involving all project-affected stakeholders. These concepts were expanded later to include the entire project development and delivery process from planning to operations and maintenance, providing for a comprehensive approach resulting in the practice of CSS. Recent economic constraints that several state DOTs are facing have created a new emphasis on financial issues as they relate to project development generating the concept of Practical Design. Finally, the most recent development of Performance-Based Practical Design can assist in delivering optimum solutions through flexible design approaches while alleviating fears regarding liability and safety concerns though the use of analysis tools to evaluate the ultimate operational and safety performance of a geometric design.
178 The existing functional classification originally was developed to provide a means for selecting roads for federal funding as well as for defining statewide systems that included roads beyond those on the nationally recognized system. Over the years, functional classification has come to assume additional significance beyond its purpose as a framework for identifying the role of a roadway in moving motor vehicles through a network of highways. Functional classification carries with it expectations about roadway design, including its speed, capacity, design controls and criteria, and relationship to existing and future land use development. Federal legislation continues to use functional classification to determine eligibility for funding under the Federal-aid program. Transportation agencies describe roadway system performance, benchmarks, and targets using functional classifications. The universal application of the FCS has enabled its integration into many facets of local operations. Uses include local access management and traffic calming eligibility, grouping for operational and safety performances, and directing built form through local land use plans and/or zoning ordinances, subdivision regulations, and site development standards. The funding component of FCS almost ensures that it will be used locally, especially in jurisdictions that lack the wherewithal to develop their own system. An issue of concern regarding the impacts of the existing FCS on design has been its linkage to geometric design standards. Highway agencies have used this linkage as their default position, where deviations and variations from the Green Book values are often achieved though administrative waivers and design exceptions. State transportation agencies now depend on defined design guidelines as design standards as a means of avoiding agency liability because of the status given to the AASHTO Green Book and state design manuals. With these standards often closely linked to functional classification, it has fostered a degree of inflexibility in roadway designâespecially in urban streetsâthat limits an agencyâs inclination to explore flexible designs for a project that are necessitated by CSS and PBPD. Another primary issue of concern with the FCS is the singular focus on automobile-centric travel. With recent refocusing on public spaces, including streets, as an activity center as well as the recent growth in pedestrian, bicycle, and transit usage for mobility, this limited understanding of roadways is insufficient to provide guidance to planners and designers. CSS and Complete Streets have brought up the issue of multimodal transportation facilities and it has emphasized the need for considering roadways as facilities that move more than vehicles. One notable consequence of this continued reliance on the FHWA classification system is that a large share of highway funding resources have continued to be concentrated on mobility-oriented corridors, even when planning at a metropolitan or local level. Additionally, the absence of the documented
179 importance of pedestrian, bicycle, or transit oriented corridors often leads to designs that identify these uses as secondary to auto oriented travel. Two issues relative to context definition in the existing FCS are the lack of recognition of rural towns and distinctions in urban networks. The urban/rural classification is essential in assigning jurisdictional roles, operational needs, and funding allocation; however, it does not provide the perspective required to guide contextual design. Frequently, roadways pass through small towns with population less than the minimum required thresholds to be classified as urban. This results in designs that are not appropriate for the roadway context. In such cases, the surrounding land use, prevailing speeds, and transportation functions are more like urban or suburban than typical rural areas and designers need to recognize such situations and apply common sense judgments in interpreting design criteria and developing appropriate solutions or design approaches. Similarly, within urban networks one can traverse along corridors with varied user and modal needs and the current FCS does not allow for the complexity of built environments or the continuity of development from rural forests and farmlands to the urban core. While the current process may accommodate these areas through the design exception process, this effort attempts to identify harmonious design as the rule, as opposed to the exception. The Expanded FCS was developed to address these issues and provide a framework that could assist in delivering appropriately contextual designs. The classification was based on a review of globally available classification systems and on responses from a nationwide survey of transportation agencies. These reviews identified the need for the existing system to have expanded context in order to recognize the lack of suburban and rural community (Main Street) contexts and the lack of balancing modal needs. Correcting both needs encourage generalized design solutions. The proposed classification balances the simplicity of the dual context with the need for expanded context sensitivity by identifying five specific categories. These categories are based on density, land use, and building setbacks. The five categories are: 1. RURAL: areas with lowest density, few houses or structures (widely dispersed or no residential, commercial and industrial uses) and usually large setbacks. 2. RURAL TOWN: areas with low to medium density but diverse land uses with commercial main street character, potential for on-street parking and sidewalks, and small setbacks.
180 3. SUBURBAN: areas with low to medium density, mixed land uses within and among structures (including mixed-use town centers, commercial corridors and residential areas) and with varied setbacks. 4. URBAN: areas with high density, mixed land uses and prominent destinations, potential for some on-street parking and sidewalks, and mixed setbacks. 5. URBAN CORE: areas with highest density and mixed land uses within and among predominately high-rise structures, and with small setbacks. The Expanded FCS defines roadway types based on their network function and the connectivity they provide among various areas. The existing names of the categories were utilized to allow for an easier transition to the proposed system as well as to retain consistency with existing funding mechanisms and other uses of the functional classification. The network function is defined based on the national, regional, and local importance of the roadway. The connectivity identifies the types of activity centers and locales that are connected with the particular roadway. The proposed roadway types are as follows: 1. INTERSTATES/FREEWAYS/EXPRESSWAYS: Corridors of national importance connecting large centers of activity over long distances. 2. PRINCIPAL ARTERIALS: Corridors of regional importance connecting large centers of activity. 3. MINOR ARTERIALS: Corridors of regional or local importance connecting centers of activity. 4. COLLECTORS: Roadways of lower local importance providing connections between arterials and local roads. 5. LOCALS: Roads with no regional or local importance; for local circulation and access only. It should be noted that the Expanded FCS will not address context types for Interstates, Freeways, and Expressways, since designs for these facilities are based on federally developed standards with little flexibility. The Expanded FCS identifies user groups, which include drivers, pedestrians, and bicyclists. Fundamental design elements for each mode also are identified, and design ranges for each are provided based on the overall roadway network type. Various user needs should be identified from the outset and considered when balancing and making the necessary trade-offs
181 among design elements in order to develop contextually appropriate multimodal solutions. The correlation of context, roadway types, and users results in the Expanded FCS matrix. This allows for the development of a multimodal, context-based design with some degree of flexibility. Each matrix cell defines the various users (drivers, bicyclists, and pedestrians) and identifies which characteristics are to be balanced. Design teams can utilize the Expanded FCS to understand the role the roadway will play in both the environment in which it will be constructed and the role it plays within the network. Various user groups that must be accommodated within the roadway are also identified, so that their competing needs and spatial demands may be considered. To assist in balancing these needs, the importance of the roadway within the individual network of each road user is also identified. Balancing modal needs is central to Expanded FCS. It is understood that there is the possibility that the designer will not be able to provide the best facilities for all the users at all times and at the same location in all roadways. There will be instances where the mobility needs for some groups require adjustments and/or consideration of alternative routes as well as the use of revised system overlays. On high-speed arterials, for example, bicycles and pedestrians may need to be accommodated on a parallel roadway with lower speeds. Likewise, a corridor with high bicycle demand and mobility needs may require the presence of bicycle facilities that would lower speeds and possibly reduce the number of available vehicle lanes if there is limited right-of-way. Design considerations of how to achieve this are presented in the guide (NCHRP Research Report 855). Proper contextual roadway designs require an understanding of the function of the roadway within its current and expected future context and the needs of the potential roadway users. The Expanded FCS and associated design matrix can assist in identifying the preliminary requirements for proper consideration of roadway context and user needs. This approach provides the framework for determining user needs and ordering user levels on a given roadway. It assumes the planner/designer can develop alternative system/network strategies for meeting all user needs. This process can assist in providing input and refinement to the purpose and need document which establishes the framework for the design to be developed. In the end the final balancing of facilities to accommodate user needs becomes part of the process of following project development principles for achieving CSS.
182 FUTURE RESEARCH The work completed here also identified areas where additional research is needed to provide answers to the questions that were posed but not addressed due to resource limitations. The following areas of future research are recommended: 1. Case studies can be undertaken where the implementation of the Expanded FCS could be applied. This would require areawide planning to identify contexts and user networks and be carried through to identify projects in their initial stages to allow for Expanded FCS influence on designs. The development of the process and establishment of additional implementation guidance would allow for a systematic evaluation of the proposed classification. This could be accomplished either at the state level or at MPO level. 2. Another effort could explore further the guidance used to define the contexts and to determine possible ranges of values for their stratification. The Expanded FCS does not provide any metrics for the quantification of the contexts and this could be addressed in the future to allow for a more complete implementation. 3. A third effort could focus on further incorporating procedures and methods of the Highway Safety Manual (AASHTO, 2010) in estimating risk and benefits of alternative modal accommodations. This would allow a more detailed evaluation of the trade-offs required when developing design options and comparing alternatives.
