Alaska follows the Functional Classification (FC) system for the USA.
In Alaska we have a set minimum standard for locking roads based on segment type. Any road of a certain segment type must be locked at least to the rank (level) in the chart below. Roads may be locked higher for protection and special situations (areas with construction, tricky design, frequent mistakes, imaging inaccuracies, and the like), but should not be locked lower.
A great time to implement these locks is while bringing the road types of an area into compliance with the current US road type standards (FC and highway systems). Lock the roads based on type after they've been set to current US road type standards.
Note: Certain roads may be locked higher than the above minimums. Please do not lower locks unless approved by the RC or SM of Alaska.
Note: Before locking these roads to these standards, you must verify that the name of the road, direction of the road, and turn functionality is correct. If this information is not correct, it should not be locked unless we are having issues with editors in the area. The only exception here is Freeways due to the routing priority. Refer to Unlock Requests if you need a section of road altered or unlocked to correct an issue.
Alaska will use the following standards for road naming:
US Highways - US-###
State Highways - AK-###
These are the general guidelines for elevation in Alaska:
- Drivable and non-drivable segments are handled the same way with elevation.
- Set elevation to ground in most cases.
- Segment(s) passing over other segment(s), rivers, major waterways, and all bridges shall have higher elevation, relative to ground.
- Only elevate/lower the actual bridge/tunnel section of the road.
- Elevation of overlapping segments should be set relative to each other, with the lowest segment as Ground (unless a tunnel).
- Tunneled segments shall have lower elevation, relative to ground.
- Only segments that "cannot see the sky" should have negative elevation (i.e. tunnels).
- Only set elevation as low/high as necessary.
- If you use the Bridge tool to join segments, be aware that it raises the elevation of the joined segment. Lower the joined segment as appropriate.
- "Seagull" guidelines apply to elevation in Alaska.
- Bridges should be cut at the start/end of the bridge.
- Tunnels should be cut at least 15m/50ft before and after the tunnel, to allow time for the GPS to regain signal.
- Do not cut segments for elevation purposes if the bridge/tunnel starts/stops within 60m/200ft of an existing junction.