Regulatory Road Sign (R4-3)
Slower Traffic Keep Right Sign Meaning & Driving Rules
Directs slower-moving vehicles to drive in the right-hand lane to allow faster traffic to pass on the left.
Required Driver Action & Right-of-Way Protocol
Drive in the right lane unless actively overtaking another vehicle. Move right if a trailing vehicle approaches.
Detailed Overview & Purpose
The Slower Traffic Keep Right sign (R4-3) enforces the fundamental highway lane principle: the left lane is for passing, and slower traffic belongs in the right lane.
Driving slowly in the left lane blocks traffic flow and creates dangerous road rage and weaving conditions.
Key Standard & Origin: Over 30 states have enacted 'Left Lane Laws' that make cruising in the left lane illegal regardless of your speed.
Where You'll Find This Sign
Multi-lane highways, mountain grade climbing lanes, and rural expressways.
Common Driver Mistakes to Avoid
Cruising in the left lane at the exact speed limit and refusing to move over for trailing traffic.
How This Sign Appears on the DMV Knowledge & Road Test
High-frequency question on highway lane etiquette and left-lane passing rules.
Legal Penalties and Moving Violations
Blocking the left lane carries moving violation citations under state Left Lane laws.
When you encounter the official Slower Traffic Keep Right (R4-3) on a roadway, what is your legal duty?
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