| A00 | Road, major and minor categories unknown |
| A01 | Road, unseparated |
| A02 | Road, unseparated, in tunnel |
| A03 | Road, unseparated, underpassing |
| A04 | Road, unseparated, with rail line in center |
| A05 | Road, separated |
| A06 | Road, separated, in tunnel |
| A07 | Road, separated, underpassing |
| A08 | Road, separated, with rail line in center |
| A1 | Primary highways with limited access |
| A10 | Primary highways with limited access, major category |
| A11 | Primary highways with limited access or interstate hwy, unseparated |
| A12 | Primary highways with limited access or interstate hwy, unseparated in tunnel |
| A13 | Primary highways with limited access or interstate hwy, unseparated underpassing |
| A14 | Primary highways with limited access or interstate hwy, unseparated rail line in center |
| A15 | Primary highways with limited access or interstate hwy, separated |
| A16 | Primary highways with limited access or interstate hwy, separated in tunnel |
| A17 | Primary highways with limited access or interstate hwy, separated underpassing |
| A18 | Primary highways with limited access or interstate hwy, separated rail line in center |
| A2 | Primary road without limited access |
| A20 | Primary road without limited access, major category |
| A21 | Primary road without limited access, unseparated |
| A22 | Primary road without limited access, unseparated in tunnel |
| A23 | Primary road without limited access, unseparated underpassing |
| A24 | Primary road without limited access, unseparated rail line in center |
| A25 | Primary road without limited access, separated |
| A26 | Primary road without limited access, separated in tunnel |
| A27 | Primary road without limited access, separated underpassing |
| A28 | Primary road without limited access, separated rail line in center |
| A3 | Secondary and connecting road |
| A30 | Secondary state and county roads, major category |
| A31 | Secondary state and county roads, unseparated |
| A32 | Secondary state and county roads, unseparated in tunnel |
| A33 | Secondary state and county roads, unseparated underpassing |
| A34 | Secondary state and county roads, unseparated rail line in center |
| A35 | Secondary state and county roads, separated |
| A36 | Secondary state and county roads, separated in tunnel |
| A37 | Secondary state and county roads, separated underpassing |
| A38 | Secondary state and county roads, separated rail line in center |
| A4 | Local, neighborhood and rural road |
| A40 | Local, neighborhood, rural road, city street, major category |
| A41 | Local, neighborhood, rural road, city street, unseparated |
| A42 | Local, neighborhood, rural road, city street, unseparated in tunnel |
| A43 | Local, neighborhood, rural road, city street, unseparated underpassing |
| A44 | Local, neighborhood, rural road, city street, unseparated rail line in center |
| A45 | Local, neighborhood, rural road, city street, separated |
| A46 | Local, neighborhood, rural road, city street, separated in tunnel |
| A47 | Local, neighborhood, rural road, city street, separated underpassing |
| A48 | Local, neighborhood, rural road, city street, separated rail line in center |
| A5 | Vehicular trail |
| A50 | Vehicular (4WD) trail, major category |
| A51 | Vehicular (4WD) trail, unseparated |
| A52 | Vehicular (4WD) trail, unseparated in tunnel |
| A53 | Vehicular (4WD) trail, unseparated underpassing |
| A6 | Roads with special characteristics |
| A60 | At-grade ramp or connecting road not associated with a limited access hwy |
| A61 | Cul-de-sac, the closed end of a road that forms a loop or turn around |
| A62 | Traffic circle, the portion of a road or intersection of roads forming a roundabout |
| A63 | Access ramp, the portion of a road that forms a cloverleaf or limited access interchange |
| A64 | Service road, provides access to businesses and rest areas |
| A65 | Ferry crossing, passenger, seasonal |
| A66 | Ferry crossing, passenger, year-round |
| A68 | Ferry crossing, passenger, vehicular, seasonal |
| A69 | Ferry crossing, passenger, vehicular, year-round |
| A7 | Road as other thoroughfare |
| A70 | Other thoroughfare major category |
| A71 | Walkway, for pedestrians, usually unnamed |
| A72 | Stairway, stepped road for pedestrians, usually unnamed |
| A73 | Alley, road for service vehicles, located at the rear of buildings |
| A74 | Driveway, usually privately owned and unnamed |
| A75 | Road, parking area |
| B00 | Railroad, major and minor categories unknown |
| B01 | Railroad track, not in tunnel or underpassing |
| B02 | Railroad track, in tunnel |
| B20 | Railroad spur track, major category |
| B30 | Railroad yard track, major category |
| B51 | Carline, a track for street cars, trolleys, and other mass transit rail systems |
| C31 | Aerial tramway, monorail, or ski lift |