Pavement markings have definite and important functions to perform in the area of traffic control. They may be used to supplement the regulations or warnings of other devices, such as the use of stop bars in conjunction with traffic signs or signals. They may be used alone to produce results that cannot be obtained by any other device, such as guidance on winding roads and around fixed objects near the highway.

The Federal Highway Administration adopted the "MANUAL ON UNIFORM TRAFFIC CONTROL DEVICES" to provide a standard for traffic control devices. This manual has been adopted by most states including Florida.

Pavement markings are generally yellow or white in color. Yellow lines delineate the separation of traffic flows in opposing directions or mark the left boundary of the travel path at locations of particular hazard. White lines delineate the separation of traffic flows in the same direction.

Solid lines are restrictive, with double lines indicating maximum restriction. Broken lines are permissive. Line width also has importance, indicating the degree of emphasis with which the local traffic authorities are placing on traffic control. Some of the more common markings are:

• A solid yellow line delineates the left edge of a travel path. It indicates a restriction against passing on the left or delineates the left edge of pavement on a divided street or highway where there is inadequate clearance to the left of the line for making emergency stops. A double line consisting of two solid yellow lines delineates the separation between travel paths in opposite directions where passing is prohibited in both directions. Crossing this marking with care is permitted only as part of a left-turn maneuver.

• A broken yellow line is used to delineate the left edge of a travel path where travel on the other side of the line is in the opposite direction. The usual application is on the center line of a two-lane, two-way roadway where overtaking and passing is permitted.

• A double line consisting of a broken yellow line and solid yellow line delineates a separation between travel paths in opposite directions where overtaking and passing is permitted for traffic adjacent to the broken line and is prohibited for traffic adjacent to the solid line. It is used on two-way, two and three-lane roadways to regulate passing.

• A broken white line is used to delineate the edge of a travel path where travel is permitted in the same direction on both sides of the line. Its most frequent application is as a lane line.

• A solid white line is used to delineate the edge of a travel sides of the line but crossing the line is discouraged. The solid white line is also used as pavement edge marking. A wide solid white line is used for emphasis where the crossing requires unusual care. It is often used as a line to delineate left or right turn lanes. A double solid white line is used to delineate a travel path where travel in the same direction is permitted on both sides of the line, but crossing the line is prohibited. It is used as a channelizing line in advance of obstructions which may be passed on either side.

On occasion, a broken line is used to delineate the extension of a line through an intersection or interchange area. It has the same color as the line it extends.

Raised Reflective Pavement Markings (RPM'S) have been found to be very effective in marking roadway centerlines and lane lines especially at night and during periods of rain. Circumstances sometimes require more unusual treatments. Reversible lanes, inbound in the morning and outbound at night, and the reservation of a left-turn only lane in the center of a highway are examples of such conditions. A double broken yellow line delineates the edge of a lane in which the direction of travel is changed from time to time. In "left turn only" lanes yellow markings are placed with solid lines on the outside and broken lines on the inside of the lane. Traffic adjacent to the solid line may cross this marking only as part of a left-turn maneuver.

Pavement markings such as shoulder markings, word and symbol markings, stop lines, crosswalk lines and parking space markings are white with the following two exceptions:

1. Transverse median markings are yellow.
2. Line, word and symbol markings visible only to traffic proceeding in the wrong direction on a one-way roadway are red. This type of marking is found on exit ramps or high speed, limited access roadways.