MUTCD W12-2: Low Clearance Signs

The W12-2 sign is covered in Section 2C.25 of the Manual on Uniform Traffic Control Devices, 11th Edition. Below are the provisions from that section that describe when the sign is used and how it is placed.

What it means and when it is used

• Standard · Required (shall)
  The Low Clearance Advance (W12-2) sign (see Figure 2C-6 ) shall be used to warn road users of vertical clearances less than 14 feet 6 inches, or vertical clearances less than 12 inches above the statutory maximum vehicle height, whichever is greater.
• Guidance · Recommended (should)
  The actual clearance should be displayed on the Low Clearance (W12-2, W12-2a, and W12-2b) sign to the nearest 1 inch not exceeding the actual clearance. However, in areas that experience changes in temperature causing frost action, a reduction, not exceeding 3 inches, should be used for this condition.

Placement and mounting

• Guidance · Recommended (should)
  Clearances should be evaluated periodically to determine if additional low clearance signing is necessary, particularly when resurfacing operations have occurred, on routes onto which over-height vehicles are normally directed under the permit process, and structures that are susceptible to catastrophic failure when struck by over-height vehicles.
• Guidance · Recommended (should)
  The W12-2 sign with a supplemental distance plaque should also be placed at the nearest intersecting road or wide point in the road at which a vehicle can detour or turn around.
• Option · Permitted (may)
  The Low Clearance Overhead (W12-2a or W12-2b) sign (see Figure 2C-6 ) may be installed on the structure to supplement the advance warning sign.

Where to read the rest

• Full text: MUTCD Section 2C.25: Low Clearance Signs
• Minimum sign sizes by roadway type are in the size section for this chapter: Section 2C.03
• Mounting height, lateral offset and retroreflectivity for any sign: MUTCD sign placement guide

Related signs in Section 2C.25