Colorado/Major roads/Main

State Highway Naming

Colorado follows the state highway general guidelines, but for consistency throughout the state, Colorado uses State Highway (SH-xxx).

The approved format for State Highway naming in Colorado is: SH-##

Locking Standard

In Colorado 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.

Colorado Minimum Locking Rank Standard

Segment Type	Default locks
Freeway	5
Ramp	Highest Rank of Connected Segment
Major Highway	4
Minor Highway	3
Primary Street	2
Street	1
• • • • Ferry • • • •	5
|-|-|-|-|-|-|-|-|-| Railroad |-|-|-|-|-|-|-|-|-|	2

Functional Classification

See Colorado/Major roads for Colorado Functional Classification guidelines.

U-turns

U-turns are generally permitted in Colorado except where prohibited by posted No U-Turn signage. Left turn only signage does not prohibit U-Turns. Here is the relevant CO Revised Statute.

C.R.S. 42-4-902. Limitations on turning around

1. No vehicle shall be turned so as to proceed in the opposite direction upon any curve or upon the approach to or near the crest of a grade where such vehicle cannot be seen by the driver of any other vehicle approaching from either direction within such distance as is necessary to avoid interfering with or endangering approaching traffic.
2. The driver of any vehicle shall not turn such vehicle at an intersection or any other location so as to proceed in the opposite direction unless such movement can be made in safety and without interfering with or endangering other traffic.
3. Local and state authorities, within their respective jurisdictions, subject to the provisions of section 43-2-135 (1)(g), C.R.S., in the case of streets which are state highways, may erect “U-turn” prohibition or restriction signs at intersections or other locations where such movements are deemed to be hazardous, and, whenever official signs are so erected, no driver of a vehicle shall disobey the instructions thereof.

For Waze routing, U-turns should ONLY be enabled where they provide the potential for improved routing, which includes recovering from missed turns. A common example is a median-divided primary street that has homes/businesses with their driveways/entrances directly on it, where reaching them would otherwise require lengthy, multi-turn deviations through side roads in order to end up on the correct side of the median. The U-turn must meet the following criteria:

1. The turn can be completed in one continuous movement. This is not a specific legal requirement in Colorado, however it would be good practice for safer navigation.
2. There is at least 15 meters (49 feet) from the right edge of the legal departure lane to the right edge of the "destination" lane curb (49 foot diameter turning circle).
3. There is no sign prohibiting a U-turn.

Note that when editing, a functional U-turn can arise from more than just the U-turn flag on a road segment, such as with these common scenarios:

1. Divided roads with box (#) and partial-box (H) intersections.
2. Divided roads with explicitly-mapped inside turn lanes (interior AGC) unless the turn arrow in the U-turn direction is disabled.

To control U-turns in these scenarios, a Junction Box (JB) must be used.