Roadway Cross-Section Reallocation: A Guide (2023)

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3-1   C H A P T E R 3 Define Your Limits A street should always provide facilities with at least minimum safe dimensions for all users. Areas heavily used by people on foot, on bicycles, or using mobility devices should have even wider facilities. Many streets are not designed with multimodal users in mind, which can lead to unsafe conditions and poor community outcomes (e.g., reduced access to resources for younger and older residents). Finding opportunities to make changes may seem daunting, but many cross-section reallocation projects can be completed as part of other efforts. Capital redesign projects, maintenance or resurfacing projects, planning studies, new develop- ment, and the passage of new policies such as Vision Zero and Complete Streets all offer oppor- tunities to rethink how roadway space is allocated. Policies like Vision Zero and Complete Streets create momentum to redesign streets. Practitioners can build on this momentum to take a closer look at how their streets operate today, how they might be changed to better meet community needs, and whether there are opportunities to incorporate those changes into future projects. This chapter explores how to evaluate a cross section and determine what (if any) changes would be most appropriate to create minimum safe facilities for all users. Determine Your Project Type When an opportunity develops for an agency to change a street’s cross section, it is important to align the reallocation with agency and community priorities. Whether the primary aim is to better serve the people living near the street, to align the street design with its land-use context, to increase the street’s effectiveness within the broader transportation network, or to address known safety issues, different priorities may benefit from different treatments. An initial evaluation of the street’s physical characteristics, such as the number of travel lanes, lane widths, and curbside widths and uses, will help the agency determine which of the common roadway reallocation project types are most appropriate for the street’s context. Common project types include roadway reconfigurations (e.g., road diets), lane-width adjustments, repurposing curbside space, and two-way-to-one-way conversions. An important consideration is whether it is economically feasible to move the curbs. Projects that widen the street or leave curbs in place and build improvements behind them techni- cally reallocate existing right-of-way to other uses. Although these reallocations are not the focus of this Guide, they can be informed by the decision-making framework presented in Chapter 2. This Guide focuses on reallocation projects, which include reconstruction projects and projects on existing roads. NCHRP Web-Only Document 320: Aligning Geometric Design with Roadway Opportunities to Change a Cross Section Key Term Minimum safe dimension Each cross-section element has a minimum width to operate safely, and designing any narrower would create risks for users. Chapter 7 discusses this concept in detail.

3-2 Roadway Cross-Section Reallocation: A Guide Context identifies three main project types: new construction, reconstruction, and projects on existing roads. The principles presented herein can help inform decisions and tradeoffs for new construction projects. Confining a roadway reallocation project to the existing curb-to-curb space significantly decreases right-of-way effects (e.g., utility conflicts), environmental impacts, construction costs, and implementation timelines. Rolling roadway reallocation into a planned resurfacing project decreases construction costs still further. Projects that use the existing curb-to-curb space can be built more quickly and inexpensively, typically using lower-cost materials like pavement markings and flexible delineator posts. Conversely, more significant treatments, like moving or building curbs, installing landscaping, or shifting roadway drainage, slow down project timelines and increase costs significantly. A short-term installation using lower-cost materials can temporarily address issues and later be upgraded with more permanent materials. The following sections summarize the common types of street reallocation projects and pre- sent example project catalysts that can alert practitioners to the possible need for cross-section reallocation. Roadway Reconfigurations Roadway reconfigurations typically involve converting an existing four-lane, undivided street segment to a three-lane segment with two through lanes and a center two-way left-turn lane (see Figure 3-1). The space freed by removing one of the traffic lanes can be used for bus lanes, pedestrian refuge islands, bike lanes, sidewalks, bus shelters, parking, landscaping, or a combina- tion of these. Table 3-1 presents potential project catalysts and typical project construction types (without and with moving curbs). Readers should note that projects without moving curbs are likely to be completed more quickly and at lower cost. Reducing Lane Widths Reducing lane widths by applying pavement markings or adding a raised median is a low-cost treatment that frees space for sidewalks, landscaped areas, bicycle lanes, bus lanes, and so forth. 4 LANE 3 LANE Figure 3-1. Conversion of an existing four-lane, undivided street segment to a three-lane segment with two through lanes and a center two-way left-turn lane.

Opportunities to Change a Cross Section 3-3   Project catalyst Typical projects (without moving curbs) Typical projects (with moving curbs) • Daily vehicle volumes below capacity for existing cross section • History of left-turn and rear-end crashes • Restripe lanes • Repurpose lanes • Install flexible delineator posts along separated • Restripe lanes • Install raised center median • Install raised median for separated bicycle facilities bicycle facilities and painted curb extensions and/or install sidewalk- level bicycle facilities • Widen sidewalks • Install raised curb extensions with green infrastructure Table 3-1. Roadway reconfigurations—example project catalysts along with potential responses. Project catalyst Typical applications without moving curbs Typical applications with moving curbs • Lanes are wider than necessary for the land-use context and road type • Presence of painted center median/gore space • Restripe, including newly painted center median • Install flexible delineator posts along separated bicycle facilities and painted curb extensions • Restripe lanes • Install raised center median • Widen sidewalks • Install raised curb extensions with green infrastructure Table 3-2. Reducing lane widths—example project catalysts along with potential responses. Although current research is not conclusive, some studies have shown that lane-width adjust- ments reduce vehicle speeds (Parsons Transportation Group 2003). Table 3-2 presents potential project catalysts and typical applications (with and without moving curbs). Repurposing Curbside Space Curbside space dedicated to parking or other uses is repurposed for bus lanes, bike lanes, sidewalks, landscaping, or a combination of these. Table 3-3 presents potential project catalysts and typical applications (with and without moving curbs). One-Way Conversion Two-lane, two-way streets can be converted to one-lane, one-way streets to reduce the space needed for driving. The space freed by removing a lane can be allocated to bus lanes, pedestrian refuge islands, bicycle lanes, sidewalks, bus shelters, parking, landscaping, or a combination of these. Table 3-4 presents potential project catalysts and typical applications (with and without moving curbs). Additional Considerations In many cases, easy adjustments to a cross section may not be an option or may not be enough to ensure that a street adequately serves the surrounding community. It may be necessary to gather additional and more specialized information on how best to serve the area. The follow- ing sections present other considerations that offer additional opportunities to determine how a street’s cross section might be changed to provide minimum safe facilities to all roadway users.

3-4 Roadway Cross-Section Reallocation: A Guide Who Lives in the Area Effective planners and engineers consider the people who live near a street when deciding whether to change its cross section. Demographic information (e.g., age, income, race, disability, car ownership, and travel mode to work) provides insights into a community’s transportation needs. Such information can shed light on which areas have greater demand for public transportation, where people are more likely to walk or bike, and which areas have the highest concentrations of vulnerable populations. Insights from demographic data can also provide a strong foundation for community engagement, which is a vital component of any street redesign project. An analysis of a community’s demographics must also assess the effect of the previous transpor- tation decisions made there. For example, in the mid-twentieth century, many areas with higher concentrations of marginalized and lower-income households were demolished to make way for Project catalyst Typical applications without moving curbs Typical applications with moving curbs • The street is part of a network with parallel route options • Restripe lanes to provide one-way travel • Install flexible delineator posts along separated bicycle facilities and painted curb extensions • Restripe lanes to provide one-way travel • Install raised median for separated bicycle facilities and/or install sidewalk-level bicycle facilities • Widen sidewalks • Install raised curb extensions with green infrastructure Table 3-4. One-way conversion—example project catalysts along with potential responses. Project catalyst Typical applications without moving curbs Typical applications with moving curbs • Underused on-street parking • Off-street parking options available nearby • Presence of shoulders • Restripe lanes to remove parking or shoulders • Provide colored pavement markings to delineate bike lanes, transit-only lanes, and transit loading areas • Restripe lanes to remove parking or shoulders • Install raised center median • Install raised median for separated bicycle facilities • Install temporary parklets or “streateries” in curbside spaces • Install loading zone or pickup/dropoff zone signs • Install multimodal parking corrals • Install modular boarding platforms that allow buses to stop in the travel lane and do not interfere with street drainage • Install flexible delineator posts along separated bicycle facilities and painted curb extensions and/or install sidewalk-level bicycle facilities • Widen sidewalks • Install raised curb extensions for additional sidewalk plaza space or bus shelters • Construct floating bus stops Table 3-3. Repurposing curbside space—example project catalysts along with potential responses.

Opportunities to Change a Cross Section 3-5   highways and roads. These urban renewal projects devastated local communities and began cycles of disinvestment that continue to this day. When authorities prioritize motor vehicles over other modes and make an insufficient economic investment in an area, the result can be unsafe conditions for vulnerable road users (e.g., high-speed streets that cut off resident access to nearby resources). A review of current and past demographics can provide valuable information on priority areas where additional care is needed to integrate different travel modes within a street’s cross section. These priority areas, particularly those with a historical lack of investment and serving persistently disadvantaged communities, should be used as a starting point for reevaluating the cross-section design to better meet everyone’s needs. The Surrounding Land Use The surrounding land-use context should heavily influence the design of a street, including the number of lanes, lane widths, intersection and midblock crossing spacing, crossing distances, and design speed. Everyone, especially people walking and biking, should be able to travel safely in all land-use contexts. The connection between land use and vehicle speeds is critical because the design speed affects the amount of street space needed. Streets should be designed differently in dense, mixed- use urban areas than in low-density, single-use rural and suburban areas (Figure 3-2). NCHRP Research Report 1022: Context Classification Application: A Guide and NCHRP Web-Only Docu- ment 320: Aligning Geometric Design with Roadway Context provide additional detail on identify- ing AASHTO context classifications and aligning geometric design with roadway context. Many national and local resources can be used to identify land-use context, or context clas- sification, for a street. For example, AASHTO includes land-use contexts in the seventh edition of its Policy on Geometric Design of Highways and Streets manual—commonly referred to as the “Green Book”—to supplement the use of functional classification in roadway design. The context categories used in the Green Book were first presented in NCHRP Research Report 855: An Expanded Functional Classification System for Highways and Streets (Figure 3-3). State DOTs, such as the Florida Department of Transportation (FDOT), have developed tailored context classification frameworks based on land use. These context classification systems describe the general characteristics of land use, develop- ment patterns, and connectivity along a street, thereby providing cues to the types of users and the intensity of use expected along the street. Rural contexts tend to have more freight and vehicle users while urban contexts have more bicycle, pedestrian, and transit users in addition to motorists. Once the land-use context and potential users are identified, the existing roadway should be evaluated to determine whether it is appropriately integrating those users. Key Terms Design speed A selected speed used to determine the various geometric design features of the roadway. Operating speed The speed at which drivers are observed operating their vehicles during free-flow conditions. Context classification Context classification identifies the type of built environment that a roadway passes through according to the land use, development patterns, and roadway connectivity. The Importance of Integrating Bicyclists and Pedestrians in All Contexts People walk and bike in all land-use contexts. Everyone is a pedestrian because every trip begins and ends on foot or wheels (i.e., pedestrians or people using mobility devices). However, bicyclists and pedestrians are also the street users most vulnerable to severe injury and death from crashes. Practitioners should proactively acknowledge and work to address the lack of safe multimodal facilities for vulnerable road users.

3-6 Roadway Cross-Section Reallocation: A Guide Figure 3-3. Land-use contexts from NCHRP Research Report 855. Although a need for additional multimodal facilities may be apparent in most contexts, lim- ited funding and resources make widespread street reconstruction infeasible. Project prioritiza- tion processes help focus multimodal improvements in areas where they are most needed, such as neighborhoods where the highest number of people walk and the fewest people have access to personal vehicles. Other examples of high-priority projects include those that can fill a critical gap in the multimodal network or serve the most potential multimodal users or activity centers. Figure 3-2. Suburban street with missing cross-section components.

Opportunities to Change a Cross Section 3-7   Activity centers serve as local and regional destinations in communities and can include the following types of resources: • Parks, open spaces, trails, and recreation centers; • Commercial districts, downtowns, grocery stores, and shopping malls; • Community centers, schools, libraries, and senior centers; • Hospitals; • Universities and commercial and institutional campuses; • Sports and performance venues; • High-density housing; • Transit stops; and • Places of business. Activity centers along or surrounding a roadway can be identified and evaluated for how well multimodal networks (e.g., sidewalks and roadway crossings, bicycle facilities, and public transit) provide access to them. Such evaluation can clarify how easily bicyclists, pedestrians, and transit riders can get to their destinations by answering such questions as the following: • Are there safe crossing and travel facilities? • Are crossing facilities appropriately spaced and aligned with user desire lines to minimize travel routes? • Are transit stops ADA-accessible and aligned with adjacent activity centers? When safe crossings and travel facilities are missing or disconnected, people are discouraged from walking, bicycling, or using transit. Those who have no choice but to walk must contend with increased travel times and potential conflict with motor vehicles. Figure 3-4 illustrates a typical walking path in an area where the street primarily serves motor- ists. The distance actually walked from housing to a nearby grocery store is nearly 50% longer Figure 3-4. Illustration of common multimodal network gap impacts.

3-8 Roadway Cross-Section Reallocation: A Guide than the most direct walking route. Not only does a lack of reasonably distanced crosswalks increase pedestrian travel time, but this lack can contribute to unprotected midblock cross- ings and fatal or severe-injury pedestrian crashes. In general, streets with poor multimodal access to nearby activity centers should be prioritized for space reallocation to better integrate potential users. Traffic Contexts Traffic contexts, such as primary function, volumes for all modes, and safety characteristics, should be considered to determine whether there are mismatches between a street’s cross section and its multimodal travel and safety needs. The street function typically falls into three main categories: 1. Access streets. These provide access to destinations. Access for local traffic (entering and leaving) occurs at all points along the street to serve adjacent land uses; slow vehicular speeds allow multimodal access to take place safely and comfortably. 2. Distributor streets. These link districts and regions. Providing direct connections to other parts of the network, access occurs primarily at intersections; vehicular speeds are higher than for access roads; these have the highest separation of modes by speed. 3. Through streets. These facilitate high-speed movement of through traffic. These streets have limited access points and the highest vehicular speeds. In practice, many streets in urban and suburban areas attempt to serve both the access and dis- tributor functions. These streets, sometimes referred to as “gray” roads or “stroads,” try to serve high-speed traffic while providing frequent and direct access to land uses. (Chapter 5 provides more information about street functions and gray roads.) The street function, posted speed, and general land-use context directly correlate to the types of active transportation facilities that should be provided, as described in Figure 3-5. The trans- portation industry is moving toward greater integration of land use and street design. As noted previously, the latest edition of the AASHTO Green Book introduces five land-use contexts and corresponding design recommendations. This Guide, however, simplifies land use into two overarching contexts (rural and urban/suburban) to emphasize that safe, multimodal facilities are necessary along all urban and suburban streets, regardless of street function, posted speed, and land-use context. Agencies that have developed design standards based on transportation and land-use context should determine whether those standards provide safe bicycle and pedestrian facilities on all roads in urban and suburban areas. (Chapter 6 presents strategies for providing minimally safe multimodal facilities in constrained environments. Chapter 7 details recommended widths and components, such as buffer types, for these urban and suburban active transportation facilities.) Traffic volumes should also be considered for all travel modes. Vehicle annual average daily traffic (AADT) is often used as the main driver of street cross-section allocation decisions, with higher AADT roadways getting more vehicular travel lanes. However, the presence of certain land uses and destinations or the number of transit users, pedestrians, and bicyclists along a corridor may indicate that more road space should be given to dedicated bicycle or transit lanes, wider sidewalks, areas for landscaping and/or tree cover, and enhanced transit stops. This ensures the needs of all street users, and not just motorists, are being integrated into the street cross section. In cases where active transportation volume data is not available, or where existing volumes are low due to the lack of multimodal facilities or poor connections, methods that estimate

Opportunities to Change a Cross Section 3-9   active transportation demand may be used, such as the one described in NCHRP Report 770: Estimating Bicycling and Walking for Planning and Project Development. Low multimodal volume data, both collected and estimated, should not be used as a reason not to make multimodal improvements, because these numbers are heavily influenced by decades of vehicle-oriented street decisions. Prioritize Safety Street safety data—measured either by crash data or risk assessments—can also indicate the need to change a street’s cross section. High numbers of crashes involving bicyclists and pedestri- ans suggest the current street configuration is not meeting all users’ needs and that more robust active transportation facilities that separate users from vehicular traffic are needed. Practitioners should pay special attention when investigating midblock crashes because such crashes typically involve vehicles traveling at higher speeds, which leads to more severe injuries and fatalities. These types of crashes indicate that substantial changes to the street design are needed and that street cross-section reallocation can be part of that change. In many cases, prioritizing improvements in areas where crashes have occurred is not enough to prevent future crashes, because crash locations tend to move around a system. Because bicycle and pedestrian crashes and near misses are underreported, historical crash data can present a biased understanding of risk prevalence. In addition, the absence of crash data does not neces- sarily indicate a safe street—only that crashes have not yet occurred or were not recorded. In many cases, crash rates are low simply because bicyclists and pedestrians avoid using the street because of safety concerns. Instead of a reactive approach that does not address safety until after crashes occur, a systemic approach should be taken to improve safety across the network before crashes occur. Figure 3-5. Active transportation facilities by street function and land use. Sources: www.pedbikeimages.org / Alyson West; Alta Planning + Design; Western Transportation Institute; Kittelson & Associates, Inc. Key Term Systemic approach An approach to safety that implements countermeasures across the transportation network based on high-risk roadway features correlated with specific fatal and severe- injury crashes. For example, an agency could implement rectangular rapid-flashing beacons (RRFBs) at midblock crossings along wide, high- speed arterials to address pedestrian crashes and crash risk.

3-10 Roadway Cross-Section Reallocation: A Guide As part of this systemic approach, a street is evaluated for characteristics shown to pose a higher risk for multimodal users, including the following: • Multiple traffic lanes, • High vehicle traffic volumes, and • High vehicle speeds. Where high-risk areas coincide with indicators that vulnerable street users are likely present (e.g., areas with high bicycle and pedestrian demand, the presence of crosswalks and transit stops, and higher concentrations of vulnerable populations), additional care around street safety is needed. These indicators should be evaluated as part of a systemic analysis to identify roadway risk factors; the presence of risk factors can indicate the need for a change to improve safety. In the absence of locally identified risk factors, national guidance, including NCHRP Research Report 893: Systemic Pedestrian Safety Analysis and National Association of City Transportation Officials’ (NACTO’s) City Limits, can be used. Evaluating a street’s traffic context often reveals competing needs related to vehicular access, mobility for other roadway users, and necessary safety improvements. Although research has shown which changes reliably make streets safer for all users, these insights are often neglected in favor of prioritizing efficient vehicular travel. The decision-making framework (as was presented in Chapter 2) helps prioritize safety by includ- ing performance metrics that are more abstract or difficult to quantify, like equitable modal access and the safety effects of geometric design decisions.