Road surface marking

Road surface marking is any kind of device or material that is used on a road surface to convey official information.

Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians. Uniformity of the markings is an important factor in minimizing confusion and uncertainty about their meaning. Countries and areas categorize road surface markings in different ways.

Road surface markings are either mechanical, non-mechanical, or temporary. They can be used to delineate traffic lanes, instruct motorists and pedestrians or serve as noise generators when run across a road, or attempt to wake a sleeping driver when installed in the shoulders of a road.

There is continuous effort to improve the road marking system. and technological breakthroughs include adding reflectivity, increasing longevity and lowering installation costs.

Mechanical markers

Mechanical devices can be either raised or recessed into the road surface and either reflective or non-reflective. While generally permanent, they may also be moveable.

Bot dots (low rounded white dots), sometimes called Botts' dots after the California engineer who came up with the idea, is one type of a mechanical non-reflective raised marker. Generally they are used to mark the edges of traffic lanes, frequently in conjunction with raised reflective markers.

Bot dots are also used across a travel lane to draw the drivers attention to the road. They are frequently used in this way before toll booths to get the drivers attention so they slow down or when a significant drop in speed has happened like going into a school zone. They are normally only used in warm climates since snow plows usually remove them along with the snow.

Similar to Bot dots, "rumble strips" are commonly used for the same purpose. A rumble strip is a simple trough (typically 1 cm deep and 10 cm wide) that is ground out of the asphalt or concrete in a perpendicular line across a roadway or shoulder. Usually closely grouped together, 5 or 10 of these troughs create a loud vibration when driven over that will alert a driver to various upcoming hazards. This type of rumble strip could be used to warn a driver of an approaching stop sign in a rural area. Another form of the rumble strip is continuously placed on the shoulder of a highway to wake drivers that may fall asleep while driving. Crossing the rumble strips placed on the shoulder of the road can wake the weary driver before they drive into the ditch.

Reflective markers, known as cat's eye in some countries, are used as travel lane dividers. By being reflective, they are more visible at night and in inclement weather. White and Yellow indicate their usual message while Red is used to indicate that you are traveling the wrong direction in a lane.

These markers can also be used for other purposes such as marking the locations of fire hydrants (blue) or at gates to gated communities to indicate that emergency service vehicles have a code or device that allows them to open the gate. In some countries like the United Kingdom, raised markers are also used to mark crosswalks to assist the blind in crossing streets.

In colder climates, reflective markers can be installed below ground using an elongated narrow triangle, cut into the Road surface that allows the device to be installed below the road surface. Newer technology now allows these to be placed above ground with snowploughable rails that attempt to protect the reflective components from the snowplough blade.

Non-mechanical markers

Paint

Paint, sometimes with additives like reflective glass beads, is generally used to mark travel lanes. It is also used to mark spaces in parking lots or special purpose spaces for handicap parking (blue), loading zones, or time restricted parking areas. Colors for these applications vary by locality. Paint is a low cost marking and has been in use since approximately the early 1950's.

Paint is usually applied right after the road has been paved. The road is marked commonly by a truck called a "Striper." These trucks contain hundreds of gallons of paint stored in huge drums which sit on the bed. The markings are controlled manually or automatically by the controller who sits on the bed. Paint is run through a series of hoses under air pressure and applied to the roadway surface. After application, the paint dries fairly quickly.

Painted symbols, such as turn-lane arrows or HOV lane markers, are applied manually using templates.

Plastic

Plastics were introduced in the late 1960's and early 1970's. Being more durable generally than paint, they are commonly used to mark crosswalks, stop lines and traffic guidance such as turn lanes, HOV lanes, train crossings, pedestrian crossings, taxi lanes, and bus lanes. The plastic is applied by heating and then rolling or spraying onto the road surface. Plastic is durable, but costly.

Epoxy

Epoxy has been in use since the late 1970's and has gained popularity over the 1990's as the technology has become more affordable and reliable. This material competes directly with plastic with respect to usage and cost.

Temporary Markers

Pylons are sometimes used to separate HOV lanes from regular traffic lanes. They are also used in areas where lanes are used at different times for travel in both directions. These pylons have shafts that drop into holes in the road surface. A good example of this type of use is the Golden Gate Bridge in San Francisco.

Country specific information

United States

In the U.S., the type, placement, and graphic standards of traffic signs and road surfaces are legally regulated — the Federal Highway Administration's Manual on Uniform Traffic Control Devices is the standard, although each state produces their own manual based upon the Federal manual.

Generally white lane markings indicate a separation between lanes traveling in the same direction while yellow markings indicate opposing traffic. In some areas, such as Colorado, black material is applied on the surface before a shorter white line is painted. This improves the contrast of the marking against "white" concrete.

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