MERGE Sign Requirements

1. When a MERGE Sign Is Used

Uses a symbol to warn that two lanes of traffic are merging into one, alerting drivers in both lanes to yield and merge safely.

• Contraflow and crossover merge points
• Two-to-one tapers where both lanes carry traffic
• Lane drop approaches in active construction

2. How and Where It Applies

In the field, W4-1 Merge is typically positioned at the advance warning area, ahead of the work. Common deployments include contraflow and crossover merge points; two-to-one tapers where both lanes carry traffic; lane drop approaches in active construction. Always confirm its size, retroreflective sheeting, spacing, and placement against the CA MUTCD 2026 and the reviewing agency before finalizing the traffic control plan.

3. Placement and Application Notes

Position W4-1 advance warning area, ahead of the work.

• Place the sign where drivers have a clear, unobstructed view on approach.
• Mount at the standard height and setback from the edge of the traveled way.
• Do not mount with other signs on the same post unless space constraints require it.

4. Standard Sizes and Visibility Considerations

Typical minimum: 48" × 48" on conventional roads; 60" × 60" on expressways and freeways.

• Choose size based on roadway speed, sight distance, and mounting location.
• Maintain high retroreflectivity for maximum night and adverse-weather visibility.

5. California Notes

Used in California work zones at points where two moving lanes of traffic converge — such as a contraflow merge point, a temporary crossover merge, or a two-to-one taper where both lanes are live.

6. Common Field or Planning Mistakes

• Sign not shown at the correct advance distance for the posted speed.
• Advance warning sign missing or out of sequence on the TCP.
• Wrong size specified for the roadway classification (conventional vs. expressway).
• Sign sheeting / retroreflectivity class not noted on the plan.