Meridian lines, in addition to marking lanes, provide necessary guidelines, instructions, and restrictions on roads. Yellow and white are the most common ones. There is no difference in the roads marked by yellow or white lines as such, but only the instructions given by them are different. Their relative occurrence varies from country to country.

Soild white line: a solid white line along the curb or between two lanes means that switching lanes and overtaking is disallowed until the line changes.

Broken white line: a broken white line is found between two lanes or in the middle of the road. It means that switching lanes or overtaking is allowed and safe.

Solid yellow line: a solid yellow line between two lanes means essentially the same thing as a solid white line. A solid yellow line along the curb means that parking at the side of the road is disallowed.

Double solid yellow line: a double solid yellow line down the middle or between two lanes means that overtaking or switching lanes is dangerous and is not advisable although not disallowed. A double solid yellow line along the curb means that a specific waiting time by the side of the road is allowed, but parking and leaving is not allowed.

Double yellow solid and broken line: This is a kind of double meridian line found in the middle between two lanes with one line solid and one broken. It means that drivers on the side of the solid line are disallowed from changing lanes or overtaking, but drivers on the side of the broken line are allowed switching lanes and overtaking.