Single solid yellow line

How to read it

The MUTCD uses a solid yellow line as the left edge line on divided highways, one-way streets and ramps, and states that a single solid yellow line shall not be used as a centre line on a two-way roadway. Both the 2009 and 2023 editions say so. The driver manuals of Pennsylvania, Florida, Oregon and Michigan describe the same use, a solid yellow line along the left edge of a divided highway or one-way road. On a two-way road, a solid yellow line on the driver's side of the centre is half of a no-passing marking: Michigan's manual says not to cross it to pass.

Also searched as: solid yellow line, solid yellow line meaning.

Where California's handbook differs

California's driver handbook describes a single solid yellow line as marking the centre of a road with two-way traffic, where a driver with one lane in their direction and the solid line on their side does not pass. Caltrans' own California MUTCD (2026 edition) keeps the federal rule that a single solid yellow line is not used as a centre line on a two-way roadway.

This describes the national standard and the named states' manuals. It isn't legal advice: the law of the state where the road is decides.

Look-alikes

On the left edge of a road, the solid yellow line is an Edge line; the right edge is white. At the centre of a two-way road, the solid yellow line comes as a pair: beside a broken line (Solid yellow line beside a broken yellow line) or beside another solid one (Double solid yellow line).