30th Highest Hourly Volume
An engineering standard used to determine the size of highways. Refers to the hourly volume of vehicle traffic that will be reached only thirty times or in a year, or, for 30 hours out of the total 8,760 hours in the “design” year. From research published in A Policy on Geometric Design of Rural Highways from the American Association of State Highway Officials (AASHO) in 1965. More information: US DOT (2018)
85th Percentile Speed
An engineering standard used to determine legal speed limits. Refers to the speed at or below which 85 percent of the drivers travel on a road segment based on observed study. More Information: Strong Towns (2018)
Accessibility
People’s ability to reach desired services and activities, which is the ultimate goal of most transport activity. Can be contrasted to mobility, which is usually more narrowly about physical movement, and transportation, which often has a connotation of being about motor vehicles, especially private passenger cars. Related, accessible design (also called universal design) can refer to
facilities that are designed to accommodate people with disabilities. More information: Litman (2022)
Active Transportation
Self-propelled, human-powered transportation. Usually means walking and bicycling. Also called Active Travel and Active Mobility. More Information: Brand et al. (2021)
Automated Vehicles
Automated vehicles are those in which information and communication technology effect safety-critical control functions (e.g., steering, throttle, or braking) without direct driver input. At the most basic level, automated vehicle technology includes driver assistance technologies like adaptive cruise control and lane-keeping assist systems. The maturity of the technology is usually described on a spectrum between levels 0 to 5, where 5 represents true independent autonomy by the vehicle anywhere in all conditions. The safety and workability of the technology beyond level 1 is still experimental, in part because a human driver needs to notice and react to at least some external events and conditions by taking over with manual operation. More information: US DOT (2023), SAE International (2022), Koopman (2021), Zipper (various).
Avoid-Shift-Improve (ASI)
An evidence-based management framework for structuring policies and investments for transportation climate action. Refers to first seeking to avoid travel such as by making communities more walkable and locating housing and destinations near one another, next shift to more efficient modes such as public transit, and finally improve vehicle equipment, especially through transportation. All elements are considered essential for deep decarbonization, they are featured in order of decarbonization potential, and they each interact with one another. The ASI is a main strategy according to the Intergovernmental Panel on Climate Change. More Information: SLOCAT Partnership on Sustainable, Low Carbon Transport (2021)
Electric Bikes (E-bikes)
E-bikes are bicycles with battery-electric motors that provide pedal-assist and/or standalone throttle power. E-bikes are usually grouped in one of three classes. Class 1 is rider assistance up to 20 MPH, Class 2 is essentially Class 1 plus a throttle for exclusive power, and Class 3 is rider assistance up to 28 MPH. E-bikes come in a variety of sizes and formats, including front-loaders (i.e., bakfiets), longtails (and midtails, or something in between a conventional frame and long tail), three-wheelers, and four-wheelers. The term “pedalec” usually refers to an e-bike that only generates power when the cyclist is pedaling. Outside of the class system, e-bikes can can also be constituted with retrofit equipment. E-bikes can be privately owned or part of public sharing systems. They can be considered both active transportation considered micromobility. More Information: People for Bikes (2023)
gCO2e/MJ
A measure of climate pollution from transportation to compare impacts in a standard way across modes. Stands for grams of carbon dioxide equivalents per megajoule. Sometimes refers to direct emissions from the transportation activity only, which involves a simple calculation using readily-available fuel economy and carbon content data, and sometimes includes those emissions plus wider lifecycle emissions (usually vehicle manufacturing, vehicle end-of-life considerations, upstream fuel production impacts, and some other impacts). California’s Low Carbon Fuel Standard, one of the nation’s most rigorous regulations for transportation climate pollution, uses the lifecycle gCo2e/MJ measure and hosts an information where the data and calculations are made available. The term can also be expressed in different units (e.g. pounds instead of grams, or kWH instead of MJ).
Greenhouse Gas (GHG) Emissions Inventory
A list of emission sources and the associated emissions quantified using standardized methods. The GHG Protocol provides most generally-accepted systems.
Micromobility
Lev nev
often implicitly refers to shared
Multimodal
Diff connoations, connectivity, presence of, whole system
Transportation Climate Action
Mobility first, resource efficient mobility options enabled by technology, especially electrification and mobility tech. People first and focus on demand management
Zero Emission Vehicle (ZEV)
and why not actually zerowarr
TO COME:
American Association of State Highway and Transportation Officials (AASHTO)
Arterials
Bicycle Infrastructure Including Bikeways and Bicycle Parking
Bus Rapid Transit (BRT)
Car Dependence
Car Sewer
Climate Resilience in Transportation
Compact Development
Complete Streets
Cost of Transportation
#CrashNotAccident
Crossing
Demand Charges
Demand-Side Management
Design and Construction Standards
Door Zone
Driver Assistance Technologies
Equity in Transportation
Farebox Ratio
Four Es
First-Mile, Last Mile (FMLM)
Frontover and backover
Gentle Density
Green Book
High Comfort
High Stress
Innovative Mobility
Infotainment
Jaywalking
Jobs-Housing Balance
Land Use
Level of Service (LOS)
Lifecycle Assessment
Microtransit
Mixed-Use Development
Mobility-as-a-Service (MaaS)
Mobility Hub
Mobility Wallet
Mode
Mode Share
Mode Shift
Manual on Uniform Traffic Control Devices (MUTCD)
Particulate Matter
Public Transportation
Science-Based Targets (SBTs)
Slip Turn
Speed Bumps and Speed Humps
Speed Reduction Mechanisms
Streetlight Data
Streets vs Roads
Supply-Side Management
Systemic Safety
Three Revolutions
Traffic Calming
Transit-Oriented Development (TOD)
Transportation Demand Management (TDM(
Transportation Network Company (TNC)
Transportation Master Plan (TMP)
Transportation Technology
Total Cost of Ownership
Traffic Calming
Transformation
Technology Readiness Level (TRL)
Turn Radius
Vision Zero
Vehicle Miles Travled (VMT)
Vertical Take-off and Landing (VTOL)
Woodlands-Urban Interface (WUI)
Warrants
Zoning
Updated February 3, 2023
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