National Academies Press: OpenBook

Developing an Expanded Functional Classification System for More Flexibility in Geometric Design (2018)

Chapter: Chapter 5. Proposed Functional Classification System

« Previous: Chapter 4. Alternative Classification Systems
Page 125
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 125
Page 126
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 126
Page 127
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 127
Page 128
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 128
Page 129
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 129
Page 130
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 130
Page 131
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 131
Page 132
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 132
Page 133
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 133
Page 134
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 134
Page 135
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 135
Page 136
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 136
Page 137
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 137
Page 138
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 138
Page 139
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 139
Page 140
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 140
Page 141
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 141
Page 142
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 142
Page 143
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 143
Page 144
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 144
Page 145
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 145
Page 146
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 146
Page 147
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 147
Page 148
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 148
Page 149
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 149
Page 150
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 150
Page 151
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 151
Page 152
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 152
Page 153
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 153
Page 154
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 154
Page 155
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 155
Page 156
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 156
Page 157
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 157
Page 158
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 158
Page 159
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 159
Page 160
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 160
Page 161
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 161
Page 162
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 162
Page 163
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 163
Page 164
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 164
Page 165
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 165
Page 166
Suggested Citation:"Chapter 5. Proposed Functional Classification System." National Academies of Sciences, Engineering, and Medicine. 2018. Developing an Expanded Functional Classification System for More Flexibility in Geometric Design. Washington, DC: The National Academies Press. doi: 10.17226/25178.
×
Page 166

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

125 PROPOSED FUNCTIONAL CLASSIFICATION SYSTEM This chapter summarizes the various concepts and issues of the proposed functional classification system (referred to as Expanded FCS) and its development. A full discussion of the proposed system and demonstration of its application is provided in the accompanying Expanded FCS guide (NCHRP Research Report 855). The goal for the proposed FCS is to provide a flexible framework that replaces the existing functional classification scheme; this will facilitate optimal geometric design solutions that consider context, user needs, and road functions. In this document, the term roadway is considered to include all facilities intended for travel in the right-of-way (e.g., travel lanes, shoulders, bicycle lanes, sidewalks). ALTERNATIVE CLASSIFICATION SYSTEM DEVELOPMENT The literature review, the evaluation of current alternative systems, and the findings from the WAG workshop pointed toward the development of a system that provides better definitions of context, which transcend the urban/rural dichotomy, and fully considers modal priorities. Moreover, correlating the proposed scheme with the current FCS was considered a key to integration of the proposed system. As noted in Chapter 4, the primary objectives of the proposed classification system are context definition and modal priority considerations, while the top secondary objective was ease of use. The recommended classification scheme should: 1) strive to readily define the context as easily as possible with the available data, 2) provide for modal balancing and consideration, and 3) not require overly burdensome data collection. The Expanded FCS provides a flexible framework, which can replace the existing functional classification scheme in order to facilitate optimal geometric design solutions that take into account context, road functions, and user needs. The Expanded FCS is designed to improve information for the planner/designer so that balanced designs can be achieved through documented prioritization of roadway users. The Expanded FCS delivers enhanced information better to inform the design decision process. This is achieved by providing increased resolution of the roadway’s design context to understand the role the roadway plays within the community; identifying the role of the roadway within the local, city, and regional transportation network; and identifying the multiple roadway user groups and their network needs within the design corridor. By providing this information within the expanded framework of the FCS, practitioners have a practical tool for determining appropriate design options and elements to understand better impacts of the trade-offs necessary to balance user needs, safety, and address other community

126 issues. The Expanded FCS framework determines user needs and orders user levels on a given roadway. It assumes the planner/designer can develop alternative system/network strategies for meeting all user needs (Figure 40). Once the content and roadway type are defined, the users can be identified, which in turn allows for the identification of possible design element options. The presence of any additional overlays (such as transit and freight) completes the required input and refines the purpose and need document, thus establishing 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. Figure 40 Expanded FCS framework

127 EXPANDED FCS COMPONENTS Context Five distinct contexts are identified in the Expanded FCS that have been determined to represent not only unique land use environments. It is recognized that a more diverse set of contexts may be identified within the built and natural environments. The five categories proposed provide general guidance so that they are applicable to a wide variety of states and agencies and they identify distinctions that require wholly different geometric design practices in terms of desired operating speeds, mobility/access demands, and user groups (Figure 41). The primary factors considered within each category are • Density (existence of structures and structure types); • Land uses (primarily residential, commercial, industrial, and/or agricultural); and • Building setbacks (distance of structures to adjacent roadways). These factors are easy to identify by observing the landscape adjacent to an existing or planned roadway. There are some other features that can generally suggest points on the development continuum such as topography and soil type, land value, population density, and building square footage. All of these are relative to context, but the Expanded FCS does not rely on these features. The context categories are as follows: 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. 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.

128 Figure 41 Expanded FCS context categories The continuum is not perfectly gradual for the determining factors among the five categories and therefore some degree of situational analysis, experience, and professional judgment is required. Furthermore, in real-world situations, discontinuities will exist even when the overall assessment is clear. The Expanded FCS context assessment does not rely on a quantitative analysis (neither persons per square mile nor building square footage) and can be used in states with broad comparative development differences between urban cores or rural areas. These differences are largely a matter of scale and intensity (the activity patterns vary Rural Suburban Urban Rural Town Urban Core

129 significantly). The Expanded FCS does not provide quantitative guidance for transitional areas between categories. However, this remains an important design consideration affecting safety, function, and design detail. This is an issue that needs to be addressed at the project level and associated treatments need to be considered at that level. The context category decision becomes a possible starting point that leads to geometric design choices, as they will be influenced by the road type. These two choices—context and road type—will define the modes to be considered and their interactions. A robust CSS process (involving all stakeholders) can assist the project team in understanding the various project issues and modal needs in order to develop a contextually appropriate design. The five Expanded FCS categories and their primary factors are shown in Table 36. Table 36 Expanded FCS context categories Category Density Land Use Setback Rural Lowest (few houses or other structures) Agricultural natural resource preservation and outdoor recreation uses with some isolated residential and commercial Usually large setbacks Rural Town Low to medium (single family houses and other single purpose structures) Primarily commercial uses along a main street (some adjacent single family residential) On-street parking and sidewalks with predominately small setbacks Suburban Low to medium (single and multi-family structures and multi- story commercial) Mixed residential neighborhood and commercial clusters (includes town centers, commercial corridors, big box commercial and light industrial) Varied setbacks with some sidewalks and mostly off-street parking Urban High (multi-story, low rise structures with designated off-street parking) Mixed residential and commercial uses, with some intuitional and industrial and prominent destinations On-street parking and sidewalks with mixed setbacks Urban Core Highest (multi-story and high rise structures) Mixed commercial, residential and institutional uses within and among predominately high rise structures Small setbacks with sidewalks and pedestrian plazas Additional discussion and photographic examples for each category are presented in the Expanded FCS Guide (NCHRP Research Report 855). The roadway planning and design process should take into account anticipated future context conditions that are often defined through state, regional, and local planning documents. At the state level, there are usually long-range transportation plans that include not only vehicle transportation but also have separate plans that address the future needs of other users. Some districts may develop transportation or land use studies that address future corridors, and urban areas may have street design guidelines, all of which may influence future roadway context. It

130 should be emphasized here that some areas grow faster than projected/planned while others decline faster than expected/planned. This assessment takes some reality testing with stakeholders/officials/professionals to determine the likelihood of future context change. Roadway Types Functional classification has, for decades, relied on three general thoroughfare types for classification: arterials, collectors, and locals (more recently, arterials have been further subdivided into principal and minor, resulting in four classification types currently being used). Decades of familiarity with these terms, and many Federal funding mechanisms being based in whole or in part on these four classifications, has resulted in continued use of the same labels. The roadway types used in Expanded FCS are based on their network function and the connectivity they provide among various centers of activity. Network function is defined based on the regional and local importance of the roadway as it pertains to vehicle movement. 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. It is noted that the primary difference between the Expanded FCS and the existing functional classification system is the absence of differentiation between minor and major collectors. These roadway types were combined due to the inability to distinguish sufficiently design, operating, and modal characteristics of the two classes. Therefore, existing classifications

131 may be transferred readily from one system to the other, though special attention may be needed in addressing minor collectors. In some cases, it may be applicable to define these roadways as local roads as opposed to collector facilities. It is also noted that the major/minor collector definition currently serves as the dividing line between eligible and non-eligible roadways within rural areas for Federal-aid. Adoption of the proposed Expanded FCS will have to address this issue when providing a new definition for Federal-aid and non-Federal-aid eligible roadways. In addition to connectivity, other factors utilized in determining the roadway type may include: Efficiency of Travel. Travelers in a private vehicle will typically seek out roadways that allow them to travel to their destinations with as little delay as possible in the shortest amount of time. Therefore, higher order driver facilities should be planned within a network to connect major centers of activity. Route Spacing. Directly related to network definition is the concept of distance (or spacing) between routes. For a variety of reasons, it is not feasible to provide high-speed facilities to travel every possible trip in the most direct manner possible or in the shortest amount of time. Ideally, regular and logical spacing between routes of different classifications exists. High separation routes should be spaced at greater intervals than medium level routes, which are spaced at much greater intervals than low/no separation routes. Spacing varies considerably for different areas. In densely populated urban areas, spacing of all route types is smaller and more consistent than spacing in sparsely developed rural areas. Geographic barriers greatly influence the layout and spacing of routes. Vehicle Volumes. The amount of vehicle traffic and current and design year volumes is another indicator of the type of facility and its functional classification. The amount of vehicle traffic affects several factors, including roadway vehicular capacity, vehicular delays, and most importantly, the number of lanes required to accommodate the traffic. It is important to note that the roadway project will serve users throughout its entire design life and beyond. However, many of the design choices required to accommodate traffic under a future scenario, e.g., more lanes, may be detrimental to year of opening conditions, i.e., encouraging higher speeds and longer pedestrian crossing distances. Therefore, design recommendations should be developed with both opening year, future year, and intermediate operations in mind, while also understanding impacts on peak and off-peak operating conditions to develop the “best” or phased approach scenario for all users throughout the entire design life and not just the on peak conditions.

132 Other Networks Bicycle Networks In addition to the automobile-oriented definitions of roadway type, classifications for bicycles are also proposed to confer structure and priority for bicycle networks. Similar to automobile roadway type classifications, these facilities are categorized based on the network connectivity a facility provides. However, the network scale is modified to reflect shorter travel ranges. Three classifications of bicycle facilities are proposed. These are: • Citywide Connector (CC)—providing citywide connections, connections to major activity centers, or regional bike routes that stretch over several miles and attract a high volume of use as they serve a primary commute or recreational purpose. • Neighborhood Connector (NC)—providing neighborhood or sub-area connection, which establishes connections to higher order facilities or local activity centers such as neighborhood CCs. • Local Connector (LC)—providing local connections of short lengths, internal connections to neighborhoods, or to higher order facilities. In addition to connectivity, other factors may be used in planning a bicycle network. Each of these factors is identified and discussed below. Efficiency of Travel. Trip makers will typically seek out roadways that allow them to travel to their destinations with as little delay as possible and in the shortest amount of time. Therefore, higher order bicycle facilities should be planned within a network to connect major centers of activity by considering recreational, work/commuting, and other trip types. Mode Range. Range should also be considered, as the National Survey of Pedestrian and Bicyclist Attitudes and Behaviors Report identified an average trip length of 65 minutes, which translates to 15-20 miles (NHTSA, 2002). In establishing a bicycle network, trip lengths longer than this should factor in integration with transit facilities. Bicyclist Safety. Another issue is the vulnerability of bicyclists. Safe bicycling facilities and options should be considered. This may often require greater separation between bicyclists and traffic in order to reduce safety concerns, especially in facilities with high speeds. Route Spacing. Directly related to network definition is the concept of distance (or spacing) between routes. For a variety of reasons, it is not feasible to provide high order facilities to accommodate every possible trip in the most direct manner possible or in the shortest

133 amount of time. Ideally, regular and logical spacing between routes of different classifications exists. High separation routes should be spaced for intervals greater than medium level, which are spaced at much larger intervals than low/no separation routes. This spacing varies considerably for different areas. In densely populated urban areas, spacing of all routes types is smaller and generally more consistent than the spacing in sparsely developed rural areas. Geographic barriers greatly influence the layout and spacing of routes. Bicycle Volumes. Estimating the amount of anticipated bicycle traffic is another indicator of the type of facility and its functional classification. Future community plans to address bicycle mobility issues and options should be considered when determining the type of facility and its functional classification. The amount of bicycle traffic affects several factors, including bicycle capacity, vehicular delays, and most importantly, the level of risk associated within the bicycle and auto traffic mix. Three basic categories of bicycle volume are considered for categorization purposes: 1) low volume, including rare or occasional bicycle traffic; 2) medium volume, which sees some bicycle trips measured in bicycles per day; and 3) high volumes. Volume is measured in bicycles per hour. Each of these volumes will require a different treatment based on the context–roadway interaction. Higher order bicycle facilities with higher volumes are considered primarily for relatively dense areas for the purpose of intermodal connection, and reasonably short trips to work or shop in or between urban core, urban, and suburban areas, though rural towns may have such networks within a smaller concentration. While rural areas do not exhibit the density typically associated with successful bicycle networks, these may occur in certain circumstances. In addition, recreational users may favor longer trips and lower interruptions provided by rural roadways, and higher volumes of recreational cyclists may be found in rural areas along popular routes or near other recreational areas that attract cyclists such as rural parks. Pedestrian Networks While other modes readily lend themselves to a network planning strategy for incorporated areas, pedestrian activity accommodations may be defined by the individual context of the area. This is in part due to the relatively short range of typical pedestrian activity. Moreover, pedestrian facilities may be even more localized, such as at a storefront or at a surrounding a bus stop, and not extend throughout the entire context area. However, in denser urban areas, pedestrian activity may also cross contexts or land use boundaries, requiring the routing of pedestrian traffic through a context area to another major area

134 of activity. For example, a corridor connecting a university campus with a downtown area may require enhanced sidewalks even if the immediate context may not demand such treatment. In addition, for larger context zones, such as suburban areas, pedestrian facilities may be focused on connecting areas of potential or anticipated pedestrian activity, such as connecting a residential subdivision to another subdivision or a nearby shopping center to a transit stop. As such, it may not be necessary to continue the sidewalk or path for the entire length of the roadway but have the potential to make more meaningful connections between compatible land uses. For example, a corridor with a suburban context may not require continuous pedestrian facilities if the centers of activity with potential pedestrian traffic are discontinuous. However, where evidence of pedestrians exists or where pedestrian travel is likely expected a minimum sidewalk width should be a priority to provide improved safety for pedestrian movements outside of the high-speed traffic area. In addition to connectivity, other factors may be utilized to plan a pedestrian network including: Efficiency of Travel. Pedestrians typically seek out roadways (pathways) that let them travel to their destinations along routes they perceive as safe and interesting. Distinct from other modes, pedestrians also consider, but are less directed by, the route with the shortest travel time. Therefore, higher order pedestrian facilities should be planned within a network to connect major centers of activity and consider recreational, work/commuting, and other trip types. Mode Range. Range should also be taken into account. A typical pedestrian range of 0.25-0.50 miles is often used as an acceptable walking distance in the U.S., however, this length may increase in urban areas where walking is the preferred method of transport (NHTSA, 2002). In establishing a pedestrian network, trip lengths longer than this should factor in integration with transit and enhanced pedestrian facilities. Due to the relatively short range of pedestrian travel, the level of pedestrian activity can often be directly associated with the area’s context and land use. Pedestrian Safety. Another issue is the vulnerability of pedestrians. Safe pedestrian facilities and options should be evaluated. Providing a separation between the pedestrian facility and the traffic or expanding available sidewalk width are methods to improve safety and pedestrian comfort by reducing potential conflicts and exposure for pedestrians. This may be especially important for roadways with medium or high speeds.

135 Block Length. The length of blocks affects pedestrian travel demand. In general, desirable block lengths range between 200 to 400 feet and should not exceed 600 feet (ITE, 2010). Long blocks tend to discourage pedestrians. Pedestrian Volumes. Estimating the amount of pedestrian traffic will help determine the type of facility and its functional classification. The amount of pedestrian traffic affects several factors, including pedestrian facility capacity, vehicular delays at signalized intersections, and most importantly, the level of risk associated from jaywalking pedestrians. Four basic categories of pedestrian volume are used for classification purposes: 1) rare or occasional volume; 2) low volume, which sees a few pedestrians measured in pedestrians per day; 3) medium volume, which sees several pedestrians, measured in pedestrians per hour; and 4) high volumes measures of pedestrians per hour and over a short time period. Each of these volumes will require a different facility based on the context-roadway interaction. Expanded FCS Matrix The correlation of context, roadway types and users results in the Expanded FCS matrix (Figure 42). 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. Figure 42 Expanded FCS framework user matrix

136 The classification of the roadway types for the driver and bicycles are considered across the entire network and their combination will provide the required coverage to address and balance their needs, based on the roadway context. Pedestrian needs are also defined based on the roadway context but there is no specific network classification for facilities to accommodate their needs. It should be noted also that a corridor may transition into different contexts over its length and this will be reflected in the design considerations and cross sections. Overlays While the corridor planning/design team often directly addresses the inclusion of auto, bicycle, and pedestrian users, other users may exist. These users, such as transit and freight, are established to meet the unique needs of the system and the network in which they operate. These users may then be applied to the corridor as overlays that add to the understanding of the total users for the roadway. When considering balancing needs of overlays, information regarding the frequency, use, and importance of the individual routes within the overlay network is essential, as discussed below. Transit Networks Transit routes are typically fixed and well defined by the local transit agency to meet the demands of transit ridership. Additional resources are available to determine the best network and routing plans for transit facilities as well as guides to aid in the design of transit facilities (AASHTO, 2014). It is imperative to incorporate transit facilities into the overall transportation network so that they can be considered in the context of the overall transportation network and not be viewed separately. Increased recent ridership trends may require a closer examination of such overlays and their potential impacts on design. A closer coordination with transit agencies, which typically are independent from DOTs, is essential to define properly transit overlays for roadways where transit either exists or is anticipated to be located. Freight Networks Freight networks typically describe where large trucks that require high-type accommodation may be concentrated on the roadway network. Studying land use to identify industrial centers, multimodal ports, manufacturing, and commercial areas may determine freight networks. Once freight-generating land uses are identified, preferred supply and delivery routes can be identified that connect the centers where activity originates with expected destinations. Heavy freight is routed typically to larger, higher classification roadways, such as major and minor arterials, where

137 increased mobility is preferred. However, in addition to evaluating the roadway types to serve freight corridors, sensitive context zones, such as urban and urban core areas, should be avoided to minimize interactions between freight and vulnerable road users. Freight networks should be characterized based upon the frequency and size of expected freight traffic. Lower classification roadways may accommodate occasional through freight vehicles, while certain roadway and land use contexts may preclude large freight traffic. On heavy freight routes, the roadway, adjacent facilities, and intersections should be designed to move traffic safely and efficiently. Moderate or occasional use facilities may marginally accommodate larger freight vehicles while being designed to provide lower speeds and shorter crossing distances for other users. Within these roadway/context combinations, impacts to operational efficiencies may be experienced as freight traffic traverses the corridor. Network Overlay Application Each modal network can be assembled to determine good network layouts for each user. Once complete, these networks may be overlaid on top of one another to develop a representation of the comprehensive transportation network and users (Figure 43). This is critical for identifying conflicts between users groups so that revisions may be made to best accommodate all users— not necessarily on all roadways but within the entire transportation network.

138 Figure 43 Networks overlay

139 Incompatibilities between user groups will likely arise throughout the network planning and project development process. When these conflicts occur, the application of an alternate network strategy can be used to identify parallel routes that meet transportation needs for other user groups on routes with more compatible uses. For example, while it may be desirable to accommodate bicyclists on an arterial, heavy vehicle volumes may present a challenging trade- off decision when considering how to accommodate significant bicycle demand. In this case, parallel roads can be used to divert the bicycle traffic and establish the required separation. While it is understood easily that all users must be accommodated within the transportation system, not all roads can be all things to all people. However, all users can be supported fully by the total network. It is therefore imperative that a designer evaluates the needs of all users, as well as understands the priority of users within the route and each of their modal networks. In establishing modal networks, the primary consideration will be identifying the generators for each mode and then providing connection between major points of trip attraction or generation. For instance, a roadway in the urban core with heavy pedestrian use in retail areas should place a high priority on pedestrian movement as it serves as the point of attraction. Roadways connecting the activity center with either residential or transit centers may also need to prioritize pedestrian movements, but may also lower priority if an alternative is identified which better accommodates the mix of users, such as establishing a pedestrian only corridor closed to automobile traffic. At a minimum, the design should accommodate intended users on the road of concern or be moved to a parallel route. Where possible, enhancements should be made beginning with the highest priority user. This application of the Expanded FCS requires expansion of the documented public transportation system to include pedestrian and bicycle networks as well as to identify future connections within these networks. Transportation agencies routinely establish roadway networks and clearly understand the role of these networks. On the other hand, bicyclist and pedestrian networks are not used widely and this may pose an initial issue for the Expanded FCS implementation. Due to the relatively limited range of pedestrian activity, it may not be necessary to identify a comprehensive pedestrian network, but rather the individual context of the area may be used to determine the level of pedestrian activity, with individual projects identifying special connections to transit and adjacent contexts. The longer range of bicycle travel, however, has the tendency to pass routinely through several context zones, increasing the need for an extended network determination of bicycle facilities. A process to identify these could be undertaken through initial consultation with the appropriate stakeholders and existing facilities can be identified at this stage. For example, cities with an inventory of sidewalks and bicycle groups often have bicycling maps developed for their members. Using such resources as a starting process will provide the

140 basis for additional discussions with these stakeholders aiming to identify the relative importance for each facility within the respective network. This process can be relied on CSS principles to define modal priorities and hence establish the network classifications for bicyclist and pedestrian facilities. An agency can follow these CSS-based approaches to establish these networks: • Identify appropriate stakeholders. • Identify centers of activity that could attract and/or generate pedestrian and bicyclist activity. • Solicit stakeholder input on route choices and priorities and collect existing maps and other data. • Develop preliminary network classifications and solicit stakeholder input. • Finalize and publish pedestrian and bicyclist networks. It is noted also that the absence of a comprehensive network does not render the application of the Expanded FCS useless. As opposed to utilizing a preexisting network, a project team in conjunction with project stakeholders and public input may identify the priority of bicycle and pedestrian facilities for a roadway. This determination is dependent upon the existing and anticipated bicycle/pedestrian volumes, adjacent facilities, traffic generators and attractions both within and outside the project area or along the route in question. Addressing bicycle and pedestrian routes in this manner will allow for advancement of modal equality, however, full network planning will be required to provide a truly cohesive system. EXPANDED FCS MODAL ACCOMMODATIONS The Expanded FCS identifies user groups, which include drivers, pedestrians, and bicyclists. It should be noted that the term “driver” refers to automobile drivers, since drivers for transit and freight are handled as an overlay. Fundamental design accommodation elements for each mode are identified also, 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 among design elements in order to develop contextually appropriate multimodal solutions.

141 Driver Accommodation The metrics used to define the context-roadway interaction for drivers are the target operating speed and the balance between mobility and access. Target Operating Speed Target operating speed is grouped into three categories: Low (<30 mph), Medium (30-45), and High (>45 mph). These definitions coincide, in general, with the existing high and low design speed concepts in the Policy for Geometric Design of Highways and Streets, or Green Book (AASHTO, 2011) and can form the basis for initial designs. Speed, in general, decreases along the context continuum (from rural to urban core) as well as along the roadway type (from Principal Arterials to Locals). The speed used in the Expanded FCS is the target operating speed of the roadway. The rationale for selecting operating speed in the Expanded FCS is the need to recognize the influence of driver desire and expectations. Moreover, the goal is to develop a facility where the operating speed is close to the design speed, resulting in an environment with smaller speed differences among drivers. Smaller speed differentials could improve safety, since they will eliminate discrepancies between design speed and operating speeds, creating a more uniform speed profile among drivers. These speeds need to be considered with both existing and future volumes and contexts. The limits for each category are based on established practices and extensive research. The speed of 25 mph was considered the limit for the low-speed environments based on current trends of several urban areas to facilitate a speed limit of 25 mph. Indeed, 20 mph is considered the survivability speed for pedestrians and bicyclists in the event of a collision with a vehicle. Such collisions typically result in injuries, and non-drivers have a high chance of surviving when speeds remain at or below 20 mph. As such, speeds of 20 mph or less should be considered in areas of higher pedestrian activity in the urban and urban core environments. Target speeds for urban and rural towns have been designated as Low / Medium because of the competing issues within these contexts and the varied pedestrian and roadside environment. The designer should examine the available speed range to select the operating speed most appropriate for all users given the facilities and context. The upper limit for high speeds is based on the Green Book definition of high-speed roads, which are those with speeds of 50 mph and above.

142 Access and Mobility The typical trade-off between access and mobility presented in the existing classification system is improved in the Expanded FCS to reflect the influence of roadway and context as it changes across the various matrix categories. Access is defined as the frequency of driveways or intersections and is grouped in three categories based on distance between access points: Low (>0.75 mile), Medium (0.75-0.25 mile), and High (<0.25 mile). Mobility is defined-qualitatively-as a function congestion level. There are three categories: Low (congested conditions), Medium (some congestion), and High (no congestion; free flow). It should be noted that volumes referred to here are taken to be during the peak period. The values for the access are based on current understanding of access management concepts and principles. While it is desirable for access density to decrease on higher mobility roadways, within certain contexts this rule does not hold true, as the roadway serves as the primary means of access. Mobility levels are based on generalized concepts of the level of service (LOS) for a facility and correspond to broad values of all roadways. Expanded FCS Matrix Approach For the driver, the interaction of access and mobility varies along the context spectrum where mobility decreases from rural to urban core and access increases from rural to urban core. Figure 44 shows the interactions and relationships for the drivers. The matrix indicates how driver metrics change based on the interactions of different combinations of context and roadway. For example, when focusing on Principal Arterials, one can observe that in a rural setting, the mobility is expected to be high with low congestion levels, while access may be low with few driveways or intersections along the corridor. As the context settings change with increased density and smaller building setbacks as well as increased pedestrian volumes and proximity to the traffic stream, mobility declines (i.e., more congestion is anticipated) and access increases, which provides more opportunities to access land uses (which also change from rural character to a more developed environment). The target operating speed also changes along the context continuum, with higher speeds anticipated in rural settings. This reflects the higher mobility in these locations. Reductions in operating speed are anticipated as the context transitions to developed and urban settings. Similar changes are also noted along the roadway type categories. Mobility decreases along the spectrum of roadway type categories (from principal arterials to locals), while access increases along the same direction. Mobility increases as the roadway type rises in category, reflecting the anticipated higher mobility levels of arterials compared to local roads. In a reverse manner, access levels increase as the roadway categories decrease, reflecting

143 the greater need for access of local roads. The target speed also changes among the categories, with an increasing trend from local to arterial roads. This reflects the mobility trends noted above. The changes along both axes of the matrix enable a three-dimensional interpretation of the typical access-mobility graph used in the existing FCS. Figure 44 Expanded FCS driver interaction matrix Design Considerations The primary design consideration for drivers is mobility. Roadways regularly have diverse modal traffic. In order to address their needs, the level and type of separation provided for the other users from vehicles may require attention. These considerations should be based on the volume of motorized, pedestrian, and bicycle traffic. Increased separation may be needed between high volumes of other users and motorized traffic. This can be achieved using either barriers or with separate facilities. Additional discussion on this is provided with the other modes. Another issue to be mindful of is the fact that not all routes are conducive to bicyclists and pedestrians (i.e., high speed principal arterials). In these cases, alternative routes should be identified that could satisfy the mobility needs of these users and accommodate them as needed. However, in some restricted cases speeds must be reduced or varied to accommodate specific users more safely.

144 For principal and minor arterials in rural town and urban contexts, designers can select from a wider range of speed choices (low through medium) for motorized traffic which will help accommodate pedestrians and bicyclists and provide for a safe design for all users. Bicyclist Accommodation The primary design consideration for a bicycle facility is the level of separation between motorized and bicycle traffic. Other factors that can help determine the proper treatment of bicyclists are discussed as well. Separation Bicycle facilities generally can be categorized based on the amount of separation they provide from motorized traffic. For the purposes of the Expanded FCS, they are categorized as: • High separation — provides physical separation from traffic in the form of physical barrier or lateral buffer. • Medium separation — provides a dedicated space adjacent to motorized traffic. • Low/No separation — provides shared use facilities for motorized and non-motorized traffic. The amount of separation necessary for a facility is dependent mostly on: • The amount of bicycle traffic on the facility. • The speed of motorized traffic on the adjacent roadway. • The amount of motorized traffic on the adjacent roadway. The need for variances in separation may be demonstrated by examining two extreme examples. First, consider a high-speed urban arterial that also serves as a regional bicycle connection; it has heavy volumes of bicycle traffic. In this instance, a cycle track or even independent multi-use paths may be appropriate to serve the bicycle traffic. Providing a separate facility reduces the number of conflicts between the two modes of traffic, which may be frequent considering the high traffic volumes of both modes and the potential severity due to high speeds of the motorized facility. Conversely, at a low-speed neighborhood street serving only local riders, bicycles and vehicles may share the same space due to the low probability of conflict and low speed differential between the two modes.

145 The proposed functional classification matrix identifies a proposed level of separation that may be considered for each bicycle facility category according to roadway type and context. The following section identifies potential treatments that may be included within each of these separation levels. Low/No Separation Treatments • No specific treatment, for cases with rare or occasional bicycle traffic. • Sharrows — for cases when a bicycle lane is not feasible and they can be used either with narrow lanes, ensuring that a driver can only pass a cyclist very slowly. Medium Separation Treatments • Bike lanes — for separating bicycles from vehicular traffic. High Separation Treatments • Buffered bike lane/cycle track — for cases with high bicycle volume. • Multi-use path — for cases with high bicycle and pedestrian traffic. Expanded FCS Matrix Approach The level of separation provided should be based on speed of traffic, context and roadway type, and is defined for all three levels of bicycle traffic. The separation changes along the context continuum to reflect the effects of target operating speed (Figure 45). For example, higher speeds on Principal Arterials require some balancing of the separation based on the amount of anticipated bicycle traffic and context. For Rural and Suburban contexts, high bicycle volumes require a high separation and the designer should determine the type to be used based on the discussion provided in the next section. In all other contexts with lower speeds, a Medium separation is recommended for high volume traffic. Similarly, there are interactions between bicycle separation and roadway type. For example, on local roads, the slow-moving traffic does not require any special separation for bicyclists, and for all contexts, Low separation is recommended. It should be noted here that all options are provided in order to allow the designer to determine the appropriate facility required to accommodate bicycle traffic based on the bicycle classifications that may exist. The matrix presents the minimum accommodation that should be expected form travelers for all modes. However, these levels of accommodation may be increased to address local priorities and where sufficient space exists to provide enhancements.

146 Figure 45 Expanded FCS bicyclist interaction matrix Design Considerations Sharrows with narrow lanes may be used when the narrow lane would not cause safety concerns or exceptionally delay traffic flow, including: • Small speed differential between bicycles and vehicles. • Low volume of vehicular or bicycle traffic. • Short length bicycle facilities (<.25 miles). Narrow lanes are no more than 10 feet wide and traffic speeds are low (less than 20 mph). Conversely, sharrows with wider lanes typically provide a wide travel lane of 13–14 feet with supplemental striping and/or signing. The wider lane allows for vehicular traffic to pass cautiously slower bike traffic. It may be a solution for constrained roadways with minimal speed differentials between bicycle and vehicular traffic (<30 mph). Bike lanes, while providing space exclusive from travel lanes, do not provide physical separation. Bicycle/vehicular conflicts at intersections with turning traffic and from “dooring”

147 incidents with parked vehicles are not eliminated. Narrower bike lanes (~4 foot) should only be used when right-of-way is constrained and not in the presence of on-street parking, unless an additional buffer is provided. Additionally, bike lanes should not be used for high-speed facilities and/or facilities with a combination of high vehicular and bike traffic. In the presence of higher speed traffic or high traffic volumes, wider bike lanes are warranted to create additional separation between facilities. Off-street paths (and trails) are cycle routes that are not part of the regular street network. An ancillary consideration is the separation of bicycle users from pedestrian activities. Both of these considerations should be based on the volume of autos/pedestrian traffic and bicycle traffic as well as the anticipated speed of cyclists and autos. Vehicular speed should be targeted based on the functional classification and context of the roadway. In addition, bicycle speed may fluctuate based on the FHWA designated “Design Bicyclist” Group A, B, or C (Advanced, Basic and Children Bicyclists, respectively) (FWHA, 1992). Bicycle separation is highly contingent on the speed differential between bicycles and motorized traffic. As speeds go up, as indicated in Figure 45, separation should also increase. However, if lower volumes of bicycle traffic are anticipated and more bicycle commuting traffic is anticipated, higher bicycle speeds (and possibly increased comfort riding in traffic) may be assumed, allowing reduced separation. If conflicts arise and vehicular or bicycle traffic cannot be accommodated on parallel routes, consideration should be given to lower targeted speeds and designing the roadway (e.g., narrower lanes, lowered mobility) to achieve that, in lieu of increased separation. While bicycle facilities are aligned to fit well with the overall vehicular functional classification, it is important to remember that bicycle facilities should be considered in terms of the overall bicycle network. The overall bicycle network should be planned to allow connections to recreational cycling areas for casual users (Group B or C) and provide commuting and general transportation opportunities for Group A users. While it would be beneficial to develop a formal area-wide bicycle network that can be overlaid with vehicular, pedestrian, and transit uses, it is not necessary as long as network connectivity is considered on a project-by-project basis. Bicycle facilities can be considered longitudinal treatments along the length of the roadway, and limited intersection elements may be required. However, considerations for turns for primary junctions within the bicycle network should be incorporated into the plan such as the use of bike boxes etc.

148 The AASHTO Guide for the Development of Bicycle Facilities (AASHTO, 2012) and the NACTO Urban Bikeway Design Guide (NACTO, 2011) contain guidance to address several bicycle design issues for specific intersection issues. Access density is also a consideration with bikes, especially with cycle tracks and buffered bike lanes. In areas of high access density, the separation of bicycle traffic should be avoided because it increases the number of crossing conflicts for ingress and egress traffic. Rural bicycle facilities also necessitate additional consideration in the design process. As noted previously, bicycle networks are more prevalent within urbanized areas due the increased density allowing the shorter range of cycling to be a more effective transportation solution. However, rural areas may experience high volumes in special circumstances, often arising from high demands from recreational riders. Understanding the unique and varying needs of recreational cyclists is important in understanding the final design of the facility. For instance, routes, which experience high usage, related to bicycle club ridership may be used by experienced riders comfortable riding next to or sharing lanes with higher speed traffic, while recreational facilities surrounding parks or other attractions may attract users of all abilities and necessitate higher separation facilities due to high vehicular speeds. Pedestrian Accommodation The primary design consideration of a pedestrian facility is its width. Other factors that can help determine the proper treatment of pedestrians are also discussed. Facility Width Pedestrian facilities can be generally categorized by the width of the facility to be provided. For the purposes of this document, they are categorized as: • * — facilities require site specific consideration. • Minimum width — provides for the minimum required width based on American with Disabilities Act (ADA) requirements. • Wide width — provides for wider than minimally required width for a pedestrian facility. • Enhanced width — provides for additional space than the wider width to accommodate congregating groups of pedestrians and street furniture. The first category (noted with a *) indicates that for occasional pedestrians site specific considerations are required in order to determine whether facilities may be placed based on the

149 local conditions and consistency with future plans for the area or alternative accommodations such as providing shoulders for pedestrian/bicycle usage may be considered. Separation In addition to the facility width, separation of the pedestrian facility from the travel way is also an important consideration. However, this design element is primarily dependent on the speed of the automobile facility rather than on the level of pedestrian activity on the facility. Typically, medium and high-speed facilities will require separation from the travel way whether this is in the form of a landscaped buffer, bicycle lanes, or parking areas. For low-speed facilities, the sidewalk may be attached to the curb, directly adjacent to the travel way without a need for a buffer area. The width necessary for a facility depends on many factors, but most notably: • The amount of pedestrian traffic adjacent to the facility. • The speed of motorized traffic on the adjacent roadway and required separation. • The amount of motorized traffic on the adjacent roadway. It is noted also that the absence of physical separation of a sidewalk may reduce the available functional width of the sidewalk in areas of high speed and high volume traffic causing pedestrians to shy away from the edge of the roadway. As such, the final design of the facility should ensure both proper width and separation to meet the anticipated needs of pedestrians within a corridor. The need for variances in width may be demonstrated by examining two extreme examples. First, consider a high-speed urban arterial that also serves as a connector between large centers of activity (e.g., a university campus and the downtown area) that has heavy volumes of pedestrian traffic. In this instance, a wide or enhanced width detached facility may be appropriate to serve the pedestrian traffic. Providing a separation improves pedestrians’ comfort levels and could reduce the number of conflicts between the two modes, which may be frequent given the high traffic volumes of both facilities, and the potential severity of conflicts due to the high speeds of the motorized facility. Conversely, on a low-speed local street serving only local pedestrians, a minimum or wide width attached facility may be appropriate depending on the pedestrian volumes, thus decreasing the probability of conflicts. The proposed functional classification matrix identifies a level of facility width that may be considered for each pedestrian facility category according to roadway type and context.

150 Expanded FCS Matrix Approach The width of the pedestrian facility and separation from the travel way provided must account for the speed of the motorized traffic and is defined for the anticipated or potential levels of pedestrian traffic for each context and roadway type. The width changes along the context continuum to reflect the traffic volumes anticipated for the facility (Figure 46). For example, when designing Principal Arterials in high-speed environments there is a need to consider the pedestrian traffic volumes in order to determine the appropriate width. In this case, for Rural and Suburban contexts, high pedestrian volumes require Enhanced width (which here can be viewed as a separate facility) to establish a safe pedestrian environment, while in cases where pedestrians are present rarely or occasionally, adding pedestrian facilities requires additional consideration and appropriate facilities need to be included commensurate with pedestrian volumes. Similar considerations are developed for the other contexts with lower speeds where the anticipated pedestrian volumes would indicate the width to be provided. For the roadway type, there is no interaction between pedestrian facilities and roadway, since the designed facility width will depend on the level of pedestrian traffic. However, as noted above, medium and high speed facilities do require increased separation of pedestrian ways and the traveled way of the road. The matrix presents the minimum accommodation that should be expected from travelers for all modes. However, these levels of accommodation may be increased to address local priorities and where sufficient space exists to provide enhancements.

151 Figure 46 Expanded FCS pedestrian interaction matrix Design Considerations The primary design consideration of pedestrian facilities is the width of the sidewalk or pathway that can comfortably accommodate the demand in a given context. Pedestrian facility widths are defined as minimum per ADA requirements. This width has the ability to accommodate a high demand of pedestrians, allowing for passing single file two-way traffic. In higher density areas, pedestrians may walk several across or in larger queues, which requires wider sidewalks to accommodate high volumes of pedestrian traffic. In the most active pedestrian centers, sidewalks can serve not only as walking routes, but also as places where people congregate. In these contexts, enhanced and wider sidewalks are necessary for pedestrian groups, but also provide for activity areas and street furniture, such as waiting areas, benches, or even outdoor seating, depending upon the adjacent land use. An ancillary design consideration for pedestrian ways is deciding whether to increase separation from motorized (and bike) traffic when medium or high speeds or volumes could

152 expose pedestrians to risk or deter them from walking because they may feel uncomfortable or unsafe. In these instances, a buffer between the traffic and the pedestrians is desirable. Buffer widths vary depending on the land uses and different types can be used to create an inviting pedestrian environment. On-street parking or bicycle lanes can also act as buffer. Desirable widths vary from 2-4 feet for local and collector roadways to 5-6 feet for arterials (AASHTO, 2004b). Increased tree lawns, shielding or physical separations could be used as buffers, and in extreme cases, off-roadway pathways may provide the best pedestrian experience. In this case, one needs to be mindful of the reductions of the effective facility width due to presence of separation (e.g. trees, shrubs or grass) based on the approach and values outlined in the Highway Capacity Manual when determining the pedestrian LOS (TRB, 2010). Intersections are of particular concern to pedestrians. As such, nodal treatments and provision of appropriate pedestrian crossing treatments is critical. Where possible, for high pedestrian movements narrow crossing widths should be used. These treatments may conflict with vehicular demands, which prioritize mobility (i.e., need more lanes) or transit and freight routes, which may require wider turning radii. Consideration may be given to alternate guidance for auxiliary turning lanes, in the presence of bicycle and pedestrian traffic. Design should take into account the increased exposure and risk of other modes when auxiliary lanes, which increase crossing distance and encourage bike conflicts in light of any decrease in safety provided by the exclusion of auxiliary turn lanes. It is imperative that the designer evaluate the needs of all users, as well as understand the priority of users within the route and each of their modal networks. Transit Rider Accommodation as an Overlay Transit routes are typically fixed and well defined by the local transit agency to meet the demands of the transit ridership. As such, there are no specific considerations to be provided as in the other modes. Close coordination and cooperation with local agencies is imperative in establishing the transit overlays in order to ensure proper accommodation of transit needs. Design Considerations Transit routes may not require significant additional facilities beyond those provided for vehicular traffic, if mobility and speeds of the vehicular routes align with transit goals. However, curbside lanes should be designed to accommodate the width of the design transit vehicle — typically lane widths of 11–12 feet. Additional width may be necessary if bicycles share the curb lane with on- street low separation facilities. Nodal treatment considerations should ensure wide turning radii to accommodate transit vehicles. While low-order transit routes and infrequent turns may not require

153 special accommodation, higher priority routes for transit should have smooth turning radii to minimize unnecessary delays at turns. In addition, for high priority or express routes special controlled lanes should be considered for either bus rapid transit or light rail to designate lanes and/or areas for transit service within the right-of-way. Moreover, special operational parameters such as bus transit priority at signals may be contemplated, recognizing that this may affect the delay and travel time of other modes. Cooperation with local transit agencies will allow identifying future transit facilities and routes in order to define future needs and land uses. On bike, priority routes, which call for lower vehicle speeds, wider lanes used to accommodate transit may encourage higher speeds. When this occurs, increased separation of bike facilities may be an option to mitigate this increase in speed as well as to improve potential safety concerns due to the vulnerability of bicyclists. Nodal considerations include bus stop locations and potential bus pullouts. Pullout locations should be placed and designed based on an examination of the safe operation and specific needs of the transit provider and its users. As noted above with respect to pedestrian treatments, enhanced pedestrian facilities and connections to adjacent activity centers (such as shopping/business, transit stops or even parking in park and ride areas) should be provided. In addition, some separation of the pedestrian facilities form the roadway may be considered in order to address possible safety concerns. Freight Accommodation as an Overlay Freight routes may not require significant additional facilities beyond those provided for vehicular traffic, if mobility and speeds of vehicular routes are consistent with freight movement. However, curbside lanes should be designed to accommodate the width of the design freight vehicle — typically lane widths of 11–12 feet. Additional width may be necessary if bicycles share the curb lane with on-street low separation facilities. Nodal treatments should ensure wide turning radii to accommodate trucks. While low-order freight routes and infrequent turns may not require special accommodation, higher priority routes for freight should have smooth turning radii to minimize unnecessary delays and possibility of crashes at turns. On bike priority routes, which call for lower speeds of vehicular traffic, wider lanes used to accommodate freight may encourage higher speeds. When this occurs, increased separation of bike facilities may be imperative to avoid conflict and improve bicyclist safety.

154 EXPANDED FCS MATRIX The preceding sections identified the specific user-related issues and design considerations that need to be addressed when balancing their needs to deliver a contextually appropriate multimodal design. Figure 47 shows the complete Expanded FCS matrix, which presents the treatment options for each user (driver, bicyclist, and pedestrian) and identifies the interactions along the context and roadway type continuums. Figure 47 Expanded FCS multimodal matrix by context and roadway type Proper contextual roadway designs require an understanding of how the roadway functions in its context and the needs of the potential roadway users. The Expanded FCS matrix

155 can be used to identify preliminary requirements that should be given due consideration when assessing current and future roadway context and user needs. In a general project development approach, this process can assist with providing input and refining the purpose and need document, which establishes the framework for the design to be developed. EXPANDED FCS APPLICATION When approaching a corridor design, the design team 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, often with competing needs or spatial demands, are identified. To assist in prioritizing and balancing these needs, the importance of the project within the individual network of each road user is also highlighted. A concept that needs to be clarified from the outset is that accommodating all the users at all the times on all roadways is impossible. This approach assumes that the Expanded FCS will be initially applied to all state- maintained roadways and replace the existing functional classification system. It is anticipated that periodic reviews and revisions will be conducted (consistent with current practices) that will review the context and roadway types for each roadway and adjust them as needed to accommodate change. It is also possible that a transportation agency will elect to implement Expanded FCS in a staged approach where the changes are considered at a project level. Once a project is started, the professional will have to review the context and roadway type designations and determine whether these are applicable or require any adjustments. Once this determination is made, the team can proceed with validating each component of the classification process, including context, roadway type, and users and proceed in developing a contextual design utilizing CSS to balance project needs and community values. This process encourages the project team to be diligent in determining the complexities of the context, both current and future, as well as all other subtleties associated with the social and natural environment surrounding the project. This implies that once the appropriate matrix cell that addresses the context–roadway environment is defined, the project team could start developing the preliminary designs, considering community comprehensive plans including the future land use plan, and any other pertinent information (including zoning ordinances) in order to develop an evolving design that could address potential changes in the roadway context. The need for a robust CSS process (involving all stakeholders) is integral to the successful implementation of the Expanded FCS and development of contextually appropriate designs.

156 Each matrix cell provides a range of design options based on defined context zone and roadway type (Figure 47). Once the roadway type/context cell is identified, the modal needs and volumes need to be considered to narrow further the range of design options. During this step, the needs of the driver, bicyclist, and pedestrian, should be determined and examined. Lists with potential accommodations based on the concepts defined for each user in the previous section should be developed. Any special overlays that need to be considered, such as transit or freight routes, should be identified next. Once individual user needs are defined, they should be synthesized to identify what design trade-offs will be necessary to best accommodate all users. Alternative designs should be developed and evaluated in order to deliver context-appropriate design. However, the project may extend beyond a single context, which should be addressed through the use of transition zones. NCHRP Report 737 (Torbic et al., 2012) provides additional guidance on proper transition considerations and design. Special attention needs to be paid when speeds transition from high to low and when considering context with changes to modal accommodations. The project team needs to also consider potential future changes in the context of contemplating community needs and goals, land use plans, and other items that could have an impact on the design. Once all these individual components are selected, the cross section may be assembled and the designer needs to determine how each component can be best fitted within the available right-of-way. Available tools for evaluating different options can be used to determine the advantages and disadvantages of each alternative. For example, Highway Capacity Manual (TRB, 2010) and Highway Safety Manual (AASHTO, 2010) procedures can be employed to determine the operation and safety effects of each choice, simulation can be used to determine the impacts of integration of vehicle and bicycle facilities, Highway Capacity Manual procedures can be used to determine the operational efficiency of pedestrian and bicycle facilities. Performance Based Design concepts and principles can be implemented to evaluate safety and operational performance of alternatives. The designer needs to establish the metrics to use for these comparisons and develop a systematic process to evaluate each alternative and compare their impacts as they relate to the purpose and need goals and specific objectives. The accompanying guide developed for the Expanded FCS provides detail on how to determine: 1. Appropriate context category; 2. Appropriate roadway type; 3. Levels of accommodation needed for different modal users (priority and balance);

157 4. Use of network overlays such as transit and freight; and 5. Design considerations that may assist in balancing design needs and accommodation of competing needs on a corridor. Examples of such guidance are provided here and the reader is encouraged to review the NCHRP Research Report 855 for additional examples. The guide also presents two case studies that demonstrate the application of the Expanded FCS matrix in projects and provides guidance for the identification of possible design options to address the competing needs of the drivers, bicyclist, pedestrians, transit users, and freight. A summary of each case is also included in the following. Application Examples Single Context Example: Suburban Minor Arterial This cell defines the suburban context for a principal arterial. In this case, a roadway provides for medium speed for the driver, translating into medium mobility and medium levels of access. The appropriate facility to be provided for the bicyclists is based upon the type of bicycle facility and its use. The facility for pedestrians is based on the amount of anticipated traffic. Finally, design considerations for transit and freight will be based on the existing overlays and their presence will have an impact on the selection of design element values. In a typical suburban minor arterial, pedestrian activity may be concentrated around specific locations, and there may be a need for targeted accommodation at these locations. Possibly, areas with high pedestrian traffic will exist in the vicinity of certain land uses (e.g., commercial, educational, office, etc.) that may require appropriate facility width commensurate with the level of pedestrian traffic. High traffic will require wide sidewalks and possibly street furniture to accommodate higher volumes. The pedestrian facility should be detached and appropriate buffer placed between the traffic and the pedestrians. If on-street parking is allowed or a bicycle lane is included, then the buffer could be eliminated. The bicycle network classification will also dictate the separation of the bicyclist from the traffic. As the network changes from local to citywide connector, bicycle volumes are expected to increase, establishing a need for greater

158 separation. For local connectors, sharrows may be appropriate due to the medium vehicular speeds. Similarly, for a neighborhood connector, a bike lane may be appropriate, and for citywide connectors a buffered lane may be considered. In the event that there is not adequate space to accommodate a bicycle citywide connector, a wide bike lane may be considered as an alternative or the target operating speed for drivers may be revisited and adjusted (e.g. 5 mph lower) for the benefit of bicycle traffic and to provide a safer facility. In this case looking at accommodating bicyclists on parallel routes could be evaluated to determine its feasibility. The presence of any transit may require lane widths to accommodate the buses that use the facility if they are larger than the design vehicle selected. The same is needed if there is a freight overlay, requiring design consideration of the typical truck that uses the facility. The presence of trucks may also have implications for shoulder width and grades. Corridor Example There are frequently cases where roadways may traverse a variety of contexts and the Expanded FCS can assist in these cases as well for developing appropriately contextual designs (Figure 48). Additional consideration should be given to the context transitions and the various design features to be used. Figure 48 Corridor example Expanded FCS application

159 An issue that also merits attention is balancing modal needs and priorities along a corridor, since these may vary along the corridor. These issues are also presented here, and they form the basis for trade-offs among the often-competing needs of each user in order to develop and deliver sound contextually appropriate multimodal solutions. The example addresses a principal arterial transitioning from rural to a rural town to rural context. The issues of concern here extend beyond the accommodation of the users within each segment as discussed above. The additional concern is providing users with the appropriate clues about changes in the roadway context and accommodate them while moving through one context to the next. For the rural to rural town change, the operating target speed changes from high to low and this should be communicated to the drivers in a manner that is more expansive than signage displaying speed limit changes. Attention should be paid to transition them toward lower speeds using design features that would gradually change from the rural cross section to the rural town cross section. This may involve gradual elimination or narrowing of the shoulder, narrowing of the travel lanes, use of pavement markings, addition of gateways or roundabouts or central island medians (Torbic et al., 2012). Accommodating users in the transition zone is critical. For drivers, attention needs to be placed in providing visual clues and guidance for the required speed reduction and this should be accomplished over a transition zone with positive guidance. For bicyclists, the first step is determining whether different bicycle separation (i.e., facilities) are in place in each zone, requiring a different level of separation. In the event that there is an agreement, then the separation type could be carried forward into the transition zone and rural town context. In this case, local connectors requiring low separation could be addressed through the use of sharrows. For neighborhood and citywide connectors, a review of the separation level in the rural and rural town contexts should be undertaken to identify whether there are any differences. For example, if sharrows are used in the rural setting and bike lanes in the rural town context, transitioning to a bike lane in the transition zone is appropriate. Obviously, similar facilities in the context areas will not require additional special consideration, but they should ensure continuity in the separation level. For arterials, there is also a change in the separation level from high in the rural to medium in rural town context. This transition requires additional considerations especially when changing from a separate multi-use path to an on-street facility. Accommodating pedestrians also follows the same considerations in the rural to rural town transition. Pedestrian facilities present in the rural town may need to be extended through the transition zone and be connected with the rural context facilities. This is more significant when the

160 enhanced facility in the rural context is an off-road facility, since attention should be given for the transition to a sidewalk. Transitioning from the rural town to rural context could follow a reverse order and complement the rural to rural town transition. Case Studies Multi-Context Application This case study roadway is a principal arterial (urban-rural) that extends 10.5 miles. Figure 49 presents the two ends of corridor, urban core to rural town. It traverses the five context categories of the Expanded FCS. The analysis included aerial photography, visual survey, review of the state’s functional classification, review of city transit information and review of city/county bike information. The roadway functional type is designated principal arterial (urban/rural) by the state’s highway department. The study provides an analysis of context using the Expanded FCS methodology. Design considerations are established using the appropriate cell of Expanded FCS matrix providing ranges to accommodate drivers, bicyclists, and pedestrians. Additionally, consideration is given to any transit or freight route information as an overlay. These matrix cell ranges for each context are then translated into a cross section alternative for illustration purposes. Figure 49 Aerial views of corridor ends The roadway context starts as urban core (0.0-0.7 miles) and then transitions to urban (07- 2.5 miles) followed by a suburban area with mixed commercial and residential development (2.5- 4.4 miles) and another suburban area with primarily residential uses (4.4-6.4 miles). The rural section (6.1-10.0 miles) is interrupted from a commercial development in the vicinity of an interchange (82.-9.1 miles). The last section of the roadway is in a rural town (10.0-10.5 miles).

161 For each section of the roadway, a discussion of the driver, bicyclist, pedestrian, transit user and freight is provided that leads to considerations for the designs to be developed. As an example, the discussion for the urban core section is presented here. The complete discussion for all sections is part of the guide in NCHRP Research Report 855. Urban Core This is the urban core of the second-largest city in Kentucky that is consolidated with Fayette County; the city's 2014 population was 310,797, anchoring a metropolitan city-county area of 489,435 people and a combined two-county statistical area of 708,677 people. This Expanded FCS matrix cell defines the design considerations for the Urban Core Principal Arterial section of the corridor. The roadway context is urban core due to the small setbacks, the mixed land use (residential, commercial and institutional), and high density of buildings. Most of the buildings are high-rise, multistory, there are enhanced sidewalks with street furniture and pedestrian accommodation facilities (benches) and plazas, and there is on-street parking along most of the section. The roadway type is a principal arterial, since it provides regional network connectivity to traffic through the town and on to access the area centers of activity. The roadway operates as a one- way pair. Driver Accommodation: According to the definitions for an Urban Core Principal Arterial, the roadway should provide low operating speeds (<25 mph). Due to the Principal Arterial designation, the upper range of speeds is considered appropriate at 25 mph. This translates into medium mobility and medium levels of access. Bicyclist Accommodation: The roadway is considered a Citywide Connector as it draws ridership from all areas within the city and accesses downtown Lexington. This designation requires a medium separation treatment; a 6.5-foot bicycle lane is considered appropriate in this section of the corridor due to the lower speeds, but provides additional width for interactions with transit vehicles and parking. Pedestrian Accommodation: The land use indicates high pedestrian activity with several destinations in the area and therefore an enhanced width sidewalk is recommended. Street furniture and pedestrian plazas may be considered to accommodate aggregating pedestrians in this section.

162 Overlays: There is heavy transit demand along the corridor and the lanes need to be designed to accommodate transit buses. There is also some freight demand, mainly small delivery trucks, and this needs to be considered during the final cross section design. Recommended Cross Section The cross section in Figure 50 was developed using the matrix cell guidance provided by Expanded FCS. It features a 25 mph speed limit with a reduced number of narrow 10-foot lanes (an outside 11-foot lane to accommodate transit vehicles). Turn lanes are eliminated within the urban core to calm travel speeds and minimize pedestrian crossing distances. A wider 6.5-foot bike lane is used to increase separation from parking and transit. The cross section shows the typical little to no building setback of an urban core. Enhanced sidewalks with occasional “parklets” to facilitate pedestrian are in use. On-street parking is provided as well as transit stops. Other cross section alternatives may be reasonable and warranted. The one-way pairs culminating on the right are clearly visible in the aerial photograph below. The shadows are indicative of the high-rise and multi-story structures of the urban core. Figure 50 Cross section, urban core Single-Context Application This case study roadway is a principal arterial (urban) that extends 0.73 miles. It traverses a single context category of the Expanded FCS (Figure 51). The analysis included aerial photography, visual survey, review of the state’s functional classification, review of city transit information and review of city/county bike information. The roadway functional type is designated principal arterial (urban) by the state’s highway department. The study provides an analysis of context using the Expanded FCS methodology. Design considerations are established using the appropriate cell of

163 the Expanded FCS matrix providing ranges to accommodate drivers, bicyclists, and pedestrians. Additionally, consideration is given to any transit or freight route information as an overlay. These matrix cell ranges for each context are then translated into a cross section alternative for illustration purposes. An evaluation of alternative cross sections based on operational and safety analysis is also included. The roadway context here is urban core with commercial, institutional and residential uses. Figure 51 Aerial corridor view Urban Core This is the urban core of the largest city in Kentucky; the city's 2014 population was 741,096, anchoring a metropolitan city-county area of 1,338,433 people. This Expanded FCS matrix cell defines the design considerations for the Urban Core Principal Arterial section of the corridor. The roadway context is urban core due to the small setbacks, the mixed land use (residential, commercial and institutional), and high density of buildings. Most of the buildings are high-rise, multistory, there are enhanced sidewalks with street furniture and pedestrian accommodation facilities (benches) and plazas, and there is on-street parking along most of the section. The roadway type is a principal arterial, since it provides regional network connectivity to traffic through the town on to the area centers of activity.

164 Driver Accommodation: According to the definitions for an Urban Core Principal Arterial, the roadway should provide low operating speeds (<25 mph). Due to the Principal Arterial designation, the upper range of speeds is considered appropriate at 25 mph. This translates into medium mobility and medium levels of access. Bicyclist Accommodation: The roadway is considered a Citywide Connector as it draws ridership from all areas within the city and accesses downtown Lexington. This designation requires a medium separation treatment; a 6.5-foot bicycle lane is considered appropriate in this section of the corridor due to the lower speeds, but provides additional width for interactions with transit vehicles and parking. Pedestrian Accommodation: The land use indicates high pedestrian activity with serval destinations in the area and therefore an enhanced width sidewalk is recommended. Street furniture and pedestrian plazas may be considered to accommodate aggregating pedestrians in this section. Overlays: There is heavy transit demand along the corridor and the lanes need to be designed to accommodate transit buses. There is also some freight demand, including small delivery trucks and large WB-53 Trucks, and this needs to be considered during the final cross section design. Cross Section The existing cross section on Broadway Street has two primary drivers: 1) automobile access providing a primary east-west route across Louisville with access to the interstates (64, 65, and 264 and 2) and east west pedestrian movements as evidenced by the wide (25 foot) sidewalks. In order to serve automobile traffic, seven 10-foot travel lanes are provided, though the outside lanes provide for time of day-restricted parking. No turn lanes are present with four lanes eastbound and three lanes westbound. Broadway is also a heavily traveled transit route serving lines Express Route 23, Frequent Service Routes 2 & 31 and Local Routes 31, 49, 53, 64, 61, 66, 67, 68, & 78. The ZeroBus, a free fare downtown route, also traverses Broadway between 4th and 3rd Streets. While the 25-foot sidewalks provide ample mobility for pedestrians along the corridor, the wide street makes pedestrian crossings difficult due to longer cycle lengths required to accommodate longer pedestrian crossing times; increasing delay to drivers and pedestrians. No bike accommodations are present on the corridor. Evaluating the operations of major intersections within this section demonstrates that all intersections maintain a high LOS (LOS A or B) with minimal vehicular delay.

165 Evaluating the Pedestrian Crosswalk Score as computed by the Highway Capacity Manual a LOS of C was rated for all approaches. This LOS is based on pedestrian compliance (a function of delay, and width of crossing). The proposed cross section (Figure 52) will reduce the number of lanes from seven to five, including a center two-way left turn lane, allowing dedicated left turns at major intersections. Parking is removed except in localized areas that experience high drop-off/pick-up locations such as the Brown Theatre and ample off-street parking opportunities exist within the corridor. Outside lanes are proposed as 13 feet to better accommodate the needs of transit. Additionally, the outside lane is striped as a shared bike lane, to allow riders comfortable riding with traffic to use the facility. It is also proposed that parallel streets on W. Chestnut Street and Breckenridge be signed and striped as higher order bike routes with separate facilities due to lower volumes of vehicular traffic on these routes; rear access to all building fronting Broadway is available from these routes. It is also proposed that an expanded and improved tree lawn be provided along the sidewalk to increase separation from the vehicular traffic, as the existing sidewalk width is more than adequate to accommodate pedestrian demands. While the total pavement width is not reduced in this scenario, the opportunity exists to create curb extensions at major intersections or pedestrian crossing points to reduce crossing width and allow the use of shorter traffic signal cycle lengths, as shown in the figure below. Right turn lanes are not provided to eliminate bike–vehicle interactions when entering right-turn lanes. Figure 52 Proposed cross section

166 Vehicle LOS for the proposed alternative does degrade, with increased delays leading to a LOS C/D, but all intersections are still shown to operate within capacity during the AM and PM peak hours. Pedestrian Crosswalk LOS is improved from LOS C to LOS B due to the reduced crossing times and delays. Safety Evaluation Application of the Highway Safety Manual procedures is not possible as there is no base model available for prediction of crashes for 7-lane sections. However, individual design elements and their effect on Crash Modification Factors or the base crash model for other conditions may be evaluated to identify potential trade-offs in the design. These are summarized in Table 37. Table 37 Safety evaluation summary Each of these features can affect safety and discussions on how each can affect design alternatives are presented in the guide (NCHRP Research Report 855). Design Elements Existing Cross Section Existing CMF Proposed Cross Section Proposed CMF Notes Proportion of curb length with on-street parking 0.8 1.57 0.25 1.14 CMF Median Width 0 23.5 10 13.2 Not a direct measure of median width, but rather change in segment crashes resulting from undivided to divided Offset to roadside fixed objects 3 1.03 16 1 CMF Number of Lanes Crossed by Pedestrian 7 0.042 5 0.039 Impacts the base conditions for pedestrian involvement Number of Left Turn Lanes 2 0.81 4 0.66 CMF

Next: Chapter 6. Expanded FCS Implementation »
Developing an Expanded Functional Classification System for More Flexibility in Geometric Design Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB's National Cooperative Highway Research Program (NCHRP) Web-Only Document 230: Developing an Expanded Functional Classification System for More Flexibility in Geometric Design, which documents the methodology of NCHRP Research Report 855: An Expanded Functional Classification System for Highways and Streets builds upon preliminary engineering of a design project, including developing the purpose and need.

In particular, NCHRP Web-Only Document 230 provides additional contexts beyond urban and rural, facilitates accommodation of modes other than personal vehicles and adds overlays for transit and freight.

Two case studies illustrating an application of the expanded system to actual projects are included.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!