Double solid white line

How to read it

In the MUTCD, a double line indicates maximum or special restrictions, and a double solid white lane line is the marking where crossing between lanes going the same way is prohibited. A double solid white line can also be a channelizing line, at freeway ramps and around islands formed only by markings. Michigan's manual describes it as a line with traffic in the same direction on both sides that may not be crossed. Oregon's manual says it is usually accompanied by a sign prohibiting lane changes for a certain distance.

Also searched as: double white line.

At carpool lanes and freeway ramps

California's handbook describes double solid white lines as a barrier between a regular lane and a preferential lane, such as a carpool (HOV) lane, and near freeway on and off ramps. It says not to cross them to enter or leave an HOV lane, but to use the designated entrances and exits, and to wait for a single broken white line before changing lanes.

Look-alikes

A double yellow line separates traffic going in opposite directions; a double white line separates traffic going the same way. A single solid white line discourages crossing without prohibiting it.