MUTCD W3-5a: Reduced Speed Limit Ahead and Speed Zone Signs

The W3-5a sign is covered in Section 2C.40 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

• Guidance · Recommended (should)
  A Reduced Speed Limit Ahead (W3-5 or W3-5a) or Truck Speed Zone Ahead (W3-5c) sign (see Figure 2C-9 ) should be used to inform road users of a reduced speed zone where the speed limit is being reduced by more than 10 mph, or where engineering judgment indicates the need for advance notice to comply with the posted speed limit ahead.
• Guidance · Recommended (should)
  A VARIABLE SPEED ZONE AHEAD (W3-5b) sign (see Figure 2C-9 ) should be used to inform road users of a zone where the speed limit is varied by time of day or as conditions change.

Placement and mounting

• Standard · Required (shall)
  If used, Reduced Speed Limit, Variable Speed Zone, or Truck Speed Zone Ahead signs shall be followed by a Speed Limit (R2-1) sign (see Figure 2B-3), with the Trucks (R2-2P) plaque (see Figure 2B-3) if applicable, installed at the beginning of the zone where the speed limit applies.

Where to read the rest

• Full text: MUTCD Section 2C.40: Reduced Speed Limit Ahead and Speed Zone 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.40