Roadway Cross-Section Reallocation: A Guide (2023)

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G-1   Access road: A road whose primary street function is to provide traffic with access to local des- tinations. On access roads, traffic can access adjacent land uses at various points along the street (intersections and driveways). Access streets are characterized by slow vehicle speeds, which allow multimodal travel to take place safely and comfortably. Access Management: The coordinated planning, regulation, and design of access between streets and adjacent land uses. Effective access management facilitates the efficient and safe move- ment of people and goods by reducing the number of conflict points on the roadway system. (https://www.fdot.gov/planning/systems/programs/sm/accman/default.shtm) Advisory bike lanes: Bicycle facilities that create shoulders for bicyclists on roadways that are too narrow to accommodate standard bike lanes. Motorists may only enter advisory bike lanes when no bicyclists are present. Advisory bike lanes are appropriate on roads with low- to-moderate motor vehicle volumes and operating speeds. Advisory bike lanes are also referred to as advisory shoulders or edge-lane roads. (https://ruraldesignguide.com/mixed-traffic) Arterial streets: Roads whose primary street function is to connect regional and local centers of activity. Arterial streets serve through traffic movements and are divided into two subcategories: principal arterials (enable longer-distance traffic movement) and minor arterials (provide connections between local areas and principal arterials). In this Guide, arterial streets typically fall within the distributor road category (see distributor streets). (NCHRP Web-Only Document 230: Developing an Expanded Functional Classification System for More Flexibility in Geometric Design) Clear corners: A safety treatment that uses striping and vertical separation (e.g., flex posts) to prevent motorists from parking within 20 feet of a crosswalk or intersection. Clear corners improve visibility for all road users at intersections, reducing the likelihood of crashes. The use of clear corners can also be referred to as daylighting. (Neighborhood Slow Streets (arcgis.com)) Collector streets: Roads whose primary street function is to connect arterial streets and local roads. In this Guide, collector streets typically fall within the distributor street category (see distributor street). (NCHRP Web-Only Document 230: Developing an Expanded Functional Classification System for More Flexibility in Geometric Design) Context classification: A street classification system that identifies the type of built environment that a roadway passes through according to the land use, development patterns, and roadway connectivity. Transportation agencies use context classification to inform the planning, design, and operation of their transportation networks. (Context Classification Guide 2022_hi-res.pdf (nflr2.com)) Glossary

G-2 Roadway Cross-Section Reallocation: A Guide Contraflow lanes: Bicycle lanes designed to allow bicyclists to ride in the opposite direction of motor vehicle traffic. Contraflow bike lanes facilitate two-way bicycle traffic on one-way streets for motor vehicles. These bicycle facilities can decrease trip distance and travel times for bicyclists by eliminating out-of-direction travel. (Contra-Flow Bike Lanes | National Association of City Transportation Officials (nacto.org)) Cross-section realm: Zones within the street cross section that serve distinct functions. The ele- ments and dimensions of cross-section realms vary based on land-use context. Four standard cross-section realms are the land-use realm, the pedestrian realm, the transition realm, and the travel way realm. Cross-section realms are also referred to as cross-section zones. Cross-section zone: See cross-section realm. Daylighting: See clear corners. Design speed: The selected speed is used to determine the geometry or physical elements of the roadway. In many communities, design speed is set in relation to the posted speed on a given street. Ideally, the design speed matches the posted speed limit to provide mobility and safety for all road users. Distributor street: A street whose primary function is to provide direct connections to other parts of the street network. On distributor streets, traffic accesses adjacent land uses at limited points along the street (primarily at intersections). Distributor streets are characterized by higher vehicular speeds than access streets and consequently provide higher separation of modes by speed. Floating bus stops: Floating bus stops are median spaces between separated bike lanes and travel lanes that serve as boarding and alighting areas for transit passengers. They typically operate with in-lane transit stops, resulting in less stop delay for transit vehicles. Floating bus stops can be constructed at different elevations to provide level boarding for standard or BRT buses. Gray road: A road with no primary street function. Gray roads serve a mix of both access road (see access road) and distributor road (see distributor street) functions. Gray roads typically try to serve high-speed traffic while providing frequent and direct access to land uses via intersec- tions and driveways. Gray roads are sometimes referred to as “stroads.” Induced demand: The concept that making motor vehicle capacity improvements to a road will result in more motorists choosing to use the road than would be the case if the road were not improved. Living streets: See shared streets. Local roads: Roads whose primary function is to provide direct access to residential and commercial properties. In this Guide, local roads typically fall within the access road category (see access road). (https://nacto.org/wp-content/uploads/2020/07/NACTO_CityLimits _Spreads.pdf) Local streets: See local roads. Location-based service (LBS) data: LBS data is aggregated from smartphones and other mobile device applications. These data represent the best location available to mobile apps at a particular point in time, which could come from GPS, Wi-Fi or Bluetooth beacons, or cell-tower signaling under limited circumstances. LBS is a form of origin-destination data. Micromobility: Transportation using lightweight vehicles such as electric bikes or electric scooters that may be borrowed as part of a self-service rental program in which people rent vehicles for short-term use within a county or city.

Glossary G-3   Minimum safe dimension: The recommended width of a roadway cross-section element that provides safe travel space for the users of the cross-section element. The minimum safe dimen- sion for each cross-section element depends primarily on traffic volumes and speeds, and sec- ondarily on land-use context. The minimum safe dimensions presented in this Guide are recommendations based on state-of-the-practice research and guidance. See Chapter 7 for a detailed discussion. Neighborhood streets: Streets whose primary street function is to provide direct access to resi- dential properties. In this Guide, neighborhood streets typically fall within the local road and access road categories (see local roads and access roads). Operating speed: The speed at which drivers are observed operating their vehicles during free- flow conditions. Ideally, roadway operating speed matches the roadway design speed and posted speed limit to provide mobility and safety for all road users. Parklets: Parklets are public seating platforms that convert curbside space into vibrant com- munity space. Also known as street seats or curbside seating, parklets are often the product of a partnership between the city and local businesses, residents, or neighborhood associations. Most parklets have a distinctive design that incorporates seating, greenery, and/or bicycle racks. Parklets can help fill unmet demand for public space on busy neighborhood retail streets or commercial areas. Quick-build projects: Transportation design projects where agencies transform streets quickly using tactical materials like cones, spray chalk, and tape. Quick-build projects enable cities to try out new street designs and let neighbors experience these changes firsthand. Raising the floor: Advancing the practice in cross section decision-making to ensure streets are designed for safety for all road users as a first step. Reduced demand: The concept is that reducing motor vehicle capacity on a road will result in fewer motorists choosing to use the road. Motorists will travel by different modes, or at different times, or eliminate the trip altogether. A similar term is “traffic evaporation.” Road diet: A roadway reconfiguration that converts travel lanes to other uses, such as tran- sit lanes or bicycle lanes. Road diets have been shown to improve safety, reduce motor vehicle speeds, and increase mobility and access for all road users. Safe System Approach: An FHWA approach that aims to eliminate fatal and serious injuries for all road users. The “Safe System Approach” makes safety an ethical imperative for the designers and owners of the transportation system. The Safe System Approach has been embraced by USDOT and other leading agencies as a default for the idea of putting safety first. Other approaches and names with shared intent and values include “Safe System,” “Vision Zero,” and “Sustainable Safety.” Safe System: The idea of putting safety first. Similar terms include “Vision Zero,” “Sustainable Safety,” and “Safe System Approach” (see Safe System Approach). Shared streets: A street that is raised to sidewalk level to define a shared space for people walk- ing, biking, and driving. Textured pavement and street furniture, including bollards, help slow speeds and reinforce the shared nature of the street. Sharrow: A shared-lane marking or “sharrow” is a street marking that helps convey to motor- ists and bicyclists that they must share the roads on which they operate. Sharrows clarify where bicyclists are expected to ride and notify motorists to expect bicyclists on the road. Streatery: Curbside lanes repurposed as a restaurant and/or communal seating area.

G-4 Roadway Cross-Section Reallocation: A Guide Stroad: See gray road. Sustainable Safety: The idea of putting safety first. Similar terms include “Vision Zero,” “Safe System,” and “Safe System Approach” (see safe system approach). Systemic approach: An approach to safety that evaluates and addresses crash risk across an entire roadway system. The approach implements countermeasures across the transportation net- work based on high-risk roadway features correlated with specific fatal and severe-injury crash types. 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. Tactical materials: Materials like cones, spray chalk, and tape that can be used to quickly trans- form streets (see quick-build projects). The multiple minimums problem: The concept that the combined use of minimum dimensions for multiple cross-section elements will create safety concerns that would not otherwise exist. For example, a minimally narrow travel lane next to a minimally narrow parking lane puts motor vehicles too close to parked cars, which could result in crashes. Through road: A road whose primary street function is to facilitate the high-speed movement of through traffic. On through roads, traffic accesses trip origins and destinations via limited access points (e.g., at on- and off-ramps). Through streets are characterized by high vehicular speeds and consequently provide multimodal access via separate parallel facilities. Traffic evaporation: The concept that reducing motor vehicle capacity on a road will result in fewer motorists choosing to use the road. Motorists will travel by different modes, or at different times, or eliminate the trip altogether. A similar term is “reduced demand” (see reduced demand). Vision Zero: Safe System: The idea of putting safety first. Similar terms include “Safe System,” “Sustainable Safety,” and “Safe System Approach” (see safe system approach). Woonerf: A Dutch street design concept for a low-speed, low-volume street shared among pedes- trians, bicyclists, and motor vehicles. In a woonerf, pedestrians have priority over cars. The street is designed without a clear distinction between pedestrian and automobile space (i.e., no continuous curb) to encourage motorists to drive slowly and with caution.