Road surface marking
is any kind of device or
material that is used on a road
in order 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, and efforts exist to standardise
such markings across borders. However, countries and areas
categorize and specifiy road surface markings in different
Road surface markings are either mechanical, non-mechanical, or
temporary. They can be used to delineate traffic
, inform motorists
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
States, two states claim to be the first to have developed
center lines. According to the state of Michigan, painted
white center lines were developed by Edward N. Hines, the chairman of the Wayne
County, Michigan, Board of
They were first used on roads in Michigan around
1911. According to the state of California, Dr. June McCarroll
was the first to develop center lines, in 1917.
In 2002, a
portion of Interstate 10
designated and signed as "The Doctor June McCarroll Memorial
Freeway" in her honor.
White center lines were used in the United States until the 1971
edition of the Manual on Uniform
Traffic Control Devices
, which mandated yellow as the standard
color of center lines nationwide (after several decades of debate
on the issue).. Yellow was adopted because it was already the
standard color of warning signs, and because it was easy to teach
drivers to associate yellow lines with dividing opposing traffic
and white lines with dividing traffic in the same direction. In
turn, this greatly reduced head-on
and improved road
. The major downside to the MUTCD white-yellow
system is that yellow has slightly less contrast than white,
especially at night, so for maximum contrast, bright yellow (and
highly toxic) lead chromate
used to paint yellow lines through the end of the 20th century. As
a result, U.S. transportation workers must take special precautions
when disturbing or removing yellow lane markings.
England, the idea of painting a centre white line was first
experimented with in 1921 in Sutton Coldfield, Birmingham. Following complaints by residents over
reckless driving and several collisions, the Sutton Coldfield
Corporation decided to paint the line on Maney Corner in the area
In 1971, a correspondent for the Sutton Coldfield News
wrote an article
in the newspaper recalling the event.
Mechanical devices may be raised or recessed into the road surface,
and either reflective
non-reflective. Most are permanent; some are movable.
- Cat's eye ,
invented by Percy Shaw in the 1930s, Cat's eyes equip most major
routes in the British
Isles. They consist of four reflect lenses mounted
in a durable white rubber housing, two facing fore and two facing
aft. The housing is mounting within a cast iron shoe, which the
rubber housing sinks in to when driven over. This provides
protection from snow ploughing and allows the lenses to be
self-cleaning - they pass a rubber blade when depressed. The lenses
are available in a variety of different colours, mainly white,
yellow/orange, green, red and blue.
- Botts' dots (low rounded white
dots), named for the California Caltrans
engineer, Elbert Botts who
invented the epoxy that keeps them glued down, are 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.
Botts' dots are also used across a travel lane to draw the drivers
attention to the road. They are frequently used in this way to
alert drivers to toll booths, school zones or other significant reduction of
speed limit. They are normally only used in warm climates since
snow plows usually remove them along with
- Rumble strips are commonly used for
the same purpose. A rumble strip can be a series of simple troughs
(typically 1 cm deep and 10 cm wide) that is ground out of the
asphalt. Other alternatives, similar to the Botts' dots, use raised
strips, painted or glued to the surface. Uses can be across the
travel direction (to warn of hazards ahead) or along the travel
direction (to warn of hazards of not staying within a specific
lane). Their main way of function is creating a strong vibration
when driven over that will alert a driver to various upcoming
hazards both by sound and the physical vibration of his
White raised pavement marker near
"pea-structure" side-line on highway surface
- Reflective markers are used as travel lane dividers, to mark
the central reservation (median) or to mark exit slip-roads.
Incorporating a raised retro-reflective element, they are typically
more visible at night and in inclement weather than standard road
marking lines. The color of markers varies depending on the country
of use. Reflective markers are also referred to as raised pavement
markers, road studs, and sometimes (generically) in the UK and
Ireland as cat's eye, although this
name refers to one particular brand of product. These markers can
be used for other purposes such as marking the locations of
fire hydrants (blue) or at gates of
gated communities to indicate that
emergency service vehicles have a code or device that allows them
to open the gate. In the United Kingdom and elsewhere, raised markers are used to mark
crosswalks (crossings) to assist the blind in crossing
streets. In colder climates, reflective markers may 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 allows these to be placed above
ground with snowploughable rails that attempt to protect the
reflective components from the snowplough blade.
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, loading zones, or time restricted
parking areas. Colors for these applications vary by locality.
Paint is a low-cost marking and has been in widespread use since
approximately the early 1950s.
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 along with the application of reflective glass beads. After
application, the paint dries fairly quickly.
Painted symbols, such as turn-lane arrows or HOV
lane markers, are applied manually using templates.
One of the most common types of road marking based on its balance
between cost and performance longevity, thermoplastic binder
systems are generally based on one of three core chemistries:
, rosin esters or maleic
modified rosin esters (MMRE). Thermoplastic coatings are generally
homogeneous dry mixes of binder resins, plasticizers, glass beads
(or other optics), pigments and fillers. Their usage has increased
over paints mainly due to the performance benefits of increased
durability, retro-reflectivity and a lack of VOC solvents.
Thermoplastic markings are applied using specially designed
vehicles. The thermoplastic mix is heated the trucks to about 200°C
before being fed to the application apparatus. This is often a
screed box or ribbon gun. Immediately after the thermoplastic has
been applied, glass beads are laid onto the hot material so that
they embed before the plastic hardens. These beads provide initial
retro-reflection. As the marking wears during use and the initial
beads are lost, the beads mixed with the binder are uncovered,
providing long term reflectivity. Most thermoplastic is produced in
white and yellow colors, but other colors such as red can also be
were introduced in the late 1960s and early 1970s. Commonly
referred to as "tape" or "cold plastic," this product is
heavy-grade material with reflective beads embedded in the plastic.
It is commonly used to mark crosswalks
and traffic guidances such as
, HOV lanes
, train crossing
, pedestrian crossings
, taxi lanes
, bus lanes
. There are three ways to apply
- Overlay - The application being laid over the surface of the
pavement. Using industrial-grade rubber cement, once the tape is
combined with the pavement, it should last three years. Major
obstacles to estimated life are snow-plows, salt, and
- Inlay - The tape physically becomes part of the asphalt. Using
the heat generated in the paving process, road workers lay special
tape on the asphalt in the hardening process, and rollers compress
the two together.
- Hot Tape - This is the oldest method and is widely
disappearing. During the process, the road worker lays out
pre-manufactured shapes in the design required. Once in place, a
torch is used to melt the plastic on the surface of the road. This
is a slower process and more prone to a dull, burnt color of the
Epoxy has been in use since the late 1970s and has gained
popularity over the 1990s as the technology has become more
affordable and reliable. This material competes directly with
plastic with respect to usage and cost.
Pylons are sometimes used to separate HOV
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.
example of this type of use is the Golden Gate Bridge in San Francisco.
Country specific information
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 its 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 on the other side of the line. 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.
In California, Botts' dots are commonly used to mark lanes on most
freeways. A large number of California cities also use Botts' dots
on some (or all) major arterials.
notable exception is the City of Los Angeles, which cannot afford to maintain any raised lane
markers due to its fiscal problems, and uses only
California and Nevada, the
reflectors when present are usually the lines, and no
paint is used for additional markings. Exceptions include:
freeways built from white concrete where painted stripes are added
to make the lanes more visible through sun glare, freeways built so
wide that the risk of drifting is minimal (e.g., Interstate 5 in the Central
Valley), and freeways in areas where it snows in the
winter (since the snowplows would scrape off the Botts'
In general, single broken lines mean passing is allowed, single
solid lines mean pass only to avoid a hazard, and double solid
lines mean it is prohibited, as it often is in tunnels
. On two-lane roads, a single broken
centerline means that passing is allowed in either direction, a
double solid centerline means passing is prohibited in both
directions, and the combination of a solid line with a broken line
means that passing is allowed only from the side with the broken
line and prohibited from the side with the solid line.
Crosswalks are indicated at a minimum by a pair of white lines. On
major boulevards, crosswalks are further highlighted by zebra
stripes, which are large white rectangles in the crosswalk
perpendicular to traffic. In order to maximize the longevity of
zebra crossing stripes, they are usually applied to correspond with
the portions of the lane on which the wheels of a car are not
usually traveling, thereby reducing wear on the markings
Generally speaking, Canadian pavement marking standards are
consistent with those used throughout the United States.
Yellow lines are used to separate traffic moving in opposite
directions, and white lines are used to separate traffic moving in
the same direction, and on the shoulders of paved roads. On
one-directional roads, a yellow line appears on the left shoulder,
and a white line on the right shoulder. Passing rules are denoted
by dashed lines as in the United States. Orange painted lines are
used when the direction of the road is altered temporarily for
Broken lines that are wider and closer together than regular broken
lines are called continuity lines. When you see continuity lines on
your left side, it generally means the lane you are in is ending or
exiting and that you must change lanes if you want to continue in
your current direction. Continuity lines on your right mean your
lane will continue unaffected.
In some areas, reflective markers recessed into the pavement are
used, especially approaching curves in the road.
Ontario has several pavement marking test areas located in various
parts of the province. Perhaps the most well known location is the
eastbound lanes of Highway 401 near Belleville. Other test sites
are located on Highway 60, West of Renfrew, Highway 28 east of
Bancroft, and on Highway 37, South of Tweed. Pavement marking
manufacturers from around the world supply a variety of materials
for these sites to have their products evaluated and approved for
use on provincial highways.
Several Western European
reserve white for routine lane markings of any kind, except bus
stops and similar things. However, for example Norway has yellow
markings separating traffic directions. Many countries use yellow,
orange or red to indicate when lanes are being shifted temporarily
to make room for construction projects.
Netherlands, Germany, Sweden, and the
"naked roads" have been trialled, whereby all visible road
markings, kerbs, traffic lights, and signs are removed.
was tested in Seend, a village
in the UK county of Wiltshire, the county council
reported that accidents fell by a third, with motorists' speed
falling by an average of 5%.
It has been suggested that
naked roads force drivers to make eye contact with other road
users, and that it is this nonverbal communication
responsible for the reduction of accidents. Other have suggested
that road markings, especially with middle marker, make the road
look like a main road, triggering faster and more relaxed driving,
while no marking makes the road look like a lower quality
U.K., a broken
white line in the direction of travel, where the gaps are longer
than the painted lines, indicates the centre of the road and that
there are no hazards specific to the design and layout of the road,
ie no turnings, sharp bends ahead etc. A broken white line in which
the gaps are shorter than the painted lines indicates an upcoming
hazard, the proportion of white to black indicates the degree of
hazard ie more white means more hazard.
A double solid white line indicates that the line may not be
crossed, overtaking is permitted if it can be performed safely
without crossing the line. Solid lines can be crossed in certain
specific conditions (turn right, overtake a vehicle with a design
speed of less than 10mph or when directed to do so by a police
officer). A solid white line with a broken white line parallel to
it indicates that crossing the line is allowed for traffic in one
direction (the side closest to the broken line) and not the
Solid white lines are also used to mark the outer edges of a
A double yellow line (commonly known as just a "Double Yellow")
next to the kerb means that no parking is allowed at any time,
whilst a single yellow line is used in conjunction with signs to
denote that parking is restricted at certain times. Double and
single red lines mean that stopping is not allowed at any time or
between certain times respectively.
On many roads in the UK, reflective devices known as cat's eyes are
placed in the road. These devices reflect the light from a car's
headlights back towards the driver in order to highlight features
of the road in poor visibility or at night. The colour of cat's
eyes differs according to their location. Those defining the
division between lanes are white, red cat's eyes are placed along
the hard shoulder of a motorway or sometimes dual carriageways and
orange cat's eyes are placed along the edge of the central
reservation (median). Green cat's eyes denote joining or leaving
slip roads at junctions.
See the highwaycode
for a complete description of
UK road markings.
lines are painted on the street
either side of a pedestrian
. Motorists should not overtake, wait or park in the
, white lines are generally
used both to separate traffic flowing in the same direction and
traffic flowing in opposite directions. Yellow lines are used to
designate tram fairways, with dashed yellow lines indicating that
vehicles may drive on the tram tracks but should not delay trams,
and solid yellow lines indicating that vehicles may not drive on
the tracks. If a tram turns through an intersection, a yellow line
is used to show how far the tram hangs out to remind other drivers
not to overtake it on the inside.
Zealand follows the convention of a solid yellow line to
indicate no passing on roads with two-way traffic, it uses long
dashed white lines to indicate when passing against opposing
traffic is allowed on two-lane roads and shorter ones to
separate lanes going in the same direction.