U-Turns
U-turns are generally permitted in Missouri except where prohibited by state, local municipal law, or posted signage. U-turns are specifically prohibited at intersections controlled by a traffic signal. See MO Statute 304.341(2) for complete legal restrictions.
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 also meet the following criteria:
- The u-turn is explicitly allowed by signage or is otherwise legal and safe according to MO Statute 304.341(2).
- The turn can be completed in one continuous movement. This is not a specific legal requirement in Missouri, however would be good practice for safer navigation.
- There is at least 15 meters (49 feet) from the left edge of the legal departure lane to the right edge of the "destination" curb. This can include any median that may exist to the left of the departure lane.
- 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:
- Divided roads with box and partial-box intersections where the median segment is 15 m (49 feet) or longer.
- Divided roads with explicitly-mapped inside turn lanes unless the turn arrow in the u-turn direction is disabled.