| | Primary categories | Subcategory | Elements |
| | Physical infrastructure | Roadway type | Divided highways, undivided highways, high-occupancy vehicle lanes, on/off ramps, one-way roads, turn-only lanes, private roads, reversible lanes, and intersections | | Roadway surface | Asphalt, concrete, grating, dirt, gravel, potholes, and grass | | Roadway edge | Line markers, temporary line markers, paved or gravel shoulder, grass shoulder, grating, rails, curb, cone, and concrete barriers | | Roadway geometry | Straightways, curves, lateral crests, corners, negative obstacles, and lane width |
| | Operational constraints | Speed limit | Minimum and maximum speed limits (absolute, relative to the speed limit, and relative to surrounding traffic) | | Traffic condition | Minimal traffic and normal traffic |
| | Objects | Signage | Signs, traffic signals, crosswalks, railroad crossing, stopped buses, construction signage, first responder signals, distress signals, roadway user signals, and hand signals | | Roadway user | Vehicle types, stopped vehicles, moving vehicles (manual and autonomous), pedestrians, and cyclists | | Nonroadway user obstacle/object | Animals (e.g., dogs and deer), shopping carts, debris (e.g., pieces of tire, trash, and ladders), construction equipment, pedestrians, and cyclists |
| | Environmental conditions | Weather | Wind, rain, snow, sleet, and temperature | | Weather-induced roadway condition | Standing water, flooded roadways, icy roads, and snow on roads | | Particulate matter | Fog, smoke, smog, dust/dirt, and mud | | Illumination | Day, night, and twilight |
| | Connectivity | Vehicle | V2V communications (e.g., DSRC and Wi-Fi) and emergency vehicles | | Traffic density information | Crowdsourced data (e.g., Waze) and V2I | | Remote fleet management system | A vehicle may be supported by an operation center capable of performing remote operation | | Infrastructure sensor and communication | Work zone alerts, vulnerable road users, routing and incident management, GPS, 3D high-definition maps, pothole locations, weather data, and data on the cloud |
| | Zones | Geofencing | Central business districts, school campuses, and retirement communities | | Traffic management zone | Temporary lane closures, dynamic traffic signs, variable speed limits, temporary or nonexistent lane markings, human-directed traffic, and loading/unloading zones | | School/construction zone | Dynamic speed limits, erratic pedestrians, and vehicular behaviors | | Regions/states | Any legal, regulatory, enforcement, tort, or other considerations | | Interference zones | Tunnels, parking garages, dense foliage, limited GPS owing to tall buildings, and atmospheric conditions |
|
|
