The Advance Traffic Control symbol signs (see Figure 2C-6) include the Stop Ahead (W3-1), Yield Ahead (W3-2), and Signal Ahead (W3-3) signs. These signs shall be installed on an approach to a primary traffic control device that is not visible for a sufficient distance to permit the road user to respond to the device. The visibility criteria for a traffic control signal shall be based on having a continuous view of at least two signal faces for the distance specified.
Support
Permanent obstructions causing the limited visibility might include roadway alignment or structures. Intermittent obstructions might include foliage or parked vehicles.
Guidance
Where intermittent obstructions occur, engineering judgment should determine the treatment to be implemented.
Option
An Advance Traffic Control sign may be used for additional emphasis of the primary traffic control device, even when the visibility distance to the device is satisfactory.
An advance street name plaque may be installed above or below an Advance Traffic Control sign.
A warning beacon may be used with an Advance Traffic Control sign.
