Functional classification is a system by which roads are classified using a set of criteria selected by the Federal Highway Administration (FHWA). These criteria include not only the physical attributes of the road but also efficiency of travel, number of access points, speed limits, route spacing, actual usage, and continuity. This can lead to quite different classifications for roads that appear similar. For example, a six-lane divided road in an urbanized area may be a Collector (Primary Street); a two-lane road through the middle of a town may be a principal arterial (Major Highway).
In Waze, functional classification is used to determine road type in the United States.
Functional classification is a national standard, but functional classification maps are published by state departments of transportation. Links to functional classification maps for each state can be found in the table below.
Functional classification maps by state
| State | Interactive map | Static maps | Notes |
|---|---|---|---|
| Alabama | ALDOT | ||
| Alaska | Alaska DOT | ||
| Arizona | ADOT | ||
| Arkansas | Arkansas.gov | ||
| California | Caltrans Earth | Caltrans | |
| Colorado | CDOT MapView | ||
| Connecticut | Connecticut DOT | ||
| Delaware | DelDOT | ||
| District of Columbia | DDOT | ||
| Florida | FDOT I-Map | Only available 6am-9pm M-F, 7am-7pm Sat, unavailable Sun (Eastern time). Individual counties on Southeast wiki. | |
| Georgia | Atlanta Metro (proposed) | Statewide FC maps under review by DOT; not available online until Sep 2014(?). See forum for details. | |
| Hawaii | Hawaii DOT | ||
| Idaho | Idaho Transportation Department | ||
| Illinois | Getting Around Illinois | Illinois DOT | |
| Indiana | INDOT | ||
| Iowa | IowaDOT | ||
| Kansas | KDOT | ||
| Kentucky | Kentucky Transportation Cabinet | ||
| Louisiana | LaDOTD Interactive Online Map | LaDOTD | |
| Maine | MaineDOT | ||
| Maryland | MD SHA via nzahn1 | MD SHA | Interactive Maps transformed from MD SHA data to Google Earth(.kml) by nzahn1 |
| Massachusetts | massDOT | ||
| Michigan | MDOT PR Finder | MDOT | |
| Minnesota | MnDOT | ||
| Mississippi | MDOT | ||
| Missouri | MoDOT | ||
| Montana | MDT | ||
| Nebraska | Nebraska Department of Roads | ||
| Nevada | Nevada DOT | ||
| New Hampshire | New Hampshire DOT | ||
| New Jersey | NJDOT | ||
| New Mexico | NMDOT | ||
| New York | NY State DOT | ||
| North Carolina | NCDOT | ||
| North Dakota | NDDOT | ||
| Ohio | Ohio DOT | ||
| Oklahoma | ODOT | ||
| Oregon | ODOT TransGIS | ODOT | |
| Pennsylvania | PennDOT | ||
| Rhode Island | RI Division of Planning | ||
| South Carolina | SCDOT GIS/Mapping | ||
| South Dakota | SDDOT | ||
| Tennessee | TDOT | ||
| Texas | TxDOT Statewide Planning Map | ||
| Utah | UDOT | ||
| Vermont | VTrans | ||
| Virginia | VDOT | ||
| Washington | WSDOT | ||
| West Virginia | WV DOT | ||
| Wisconsin | WisDOT | ||
| Wyoming | Not found |