Roll Up Incident Warning Signs

Section 2C.36 Advance Traffic Control Signs

Standard

• 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.

Source: 2009 MUTCD

When to Use 36″ and 48″ Temporary Warning Signs

According to the MUTCD:

Transportation engineers may find this answer acceptable since they have a deeper understanding of the MUTCD than most, but not everyone has this knowledge. Luckily, definitions of these terms are provided to help make some sense of what they are trying to convey. Here’s how the MUTCD defines each of those types of roadways:

• "Conventional Road" is a "street or highway other than a low-volume road, expressway, or freeway."
• "Low-Volume Road" is a facility lying outside of developed areas of cities, towns, and communities, which serves fewer than 400 vehicles per day on average. A low-volume road shall not be a freeway, an expressway, an interchange ramp, a freeway service road, a road on a designated State highway system, or a residential street in a neighborhood.
• "Expressway" is a divided highway with partial control of access.
• "Freeway" is a divided highway with full control of access.

Still confused? It's not just you. Generally speaking, if the road is a divided highway with a concrete barrier or median, a 48 × 48″ sign will be required. A 36 × 36″ sign can be used on all other types of roadways.