Asphalt Paving and Sealcoat  Blog

Pavement Markings and Striping Issues

Pavement Markings Issues
Pavement marking effectiveness is based mostly on the durability and the visibility of the markings. Durability is
usually tracked by the simple amount of material remaining on the pavement surface over time, but can be more
scientifically tracked by measuring the bond strength of the material to the surface. Visibility related mostly to the
brightness and reflective nature of the material. Glass beads mixed into the pavement marking traffic grade paint
can add to the visibility by greatly increasing the material's retro-reflection characteristics.

Fading
Faded pavement markings and parking stall lines make these important traffic control devices invisible to
customers, tenants and other motorists, leading to potentially dangerous outcomes. Arrows, stop bars, and other
traffic control markings ensure the proper flow of traffic and optimize customer flow in and out of parking lots. Fire
lanes, curbing and no parking zones ensure that vehicles will not be parked in important areas and potentially
block emergency response vehicles. Furthermore, faded parking lines lead to insufficient use of parking lot space
and leading to less customer and tenant parking than the parking lot space will allow, including accessible parking
spaces.

Pavement Markings on Fresh Sealcoat
Although thermoplastic paint are the ideal type of pavement marking on sealcoated surfaces, water-based or
latex-based paints are far more economically feasible relative to their durability and visibility. Water-based or
latex-based traffic grade paints must be applied, however, after the sealcoat has properly cured; this curing can
take as little as a few hours depending on sun exposure, humidity, traffic conditions and other variables. If
sufficient curing time is not allowed for the sealcoat, traffic grade paint will being to "bleed" and discolored.
Furthermore, excess traffic on fresh sealcoat will also "scar" the pavement markings with tacky sealcoat that has
come onto vehicle tires and is tracked onto fresh pavement markings. All of these potential issues can be
avoided by allowing sealcoat proper dry times before applying pavement markings.

 

Pavement Marking Lines pt.2

Crosswalks
On roads where traffic is not controlled by signals or
stop signs, crosswalk markings warn the motorist of a
pedestrian crossing point. On controlled intersections,
crosswalk markings primarily guide pedestrians in the
proper paths. Do not use crosswalk markings indiscriminately.
Only an engineering study should recommend
installing crosswalks where there are no traffic signals
or stop signs.

Crosswalk lines are two parallel solid white lines
normally spaced 6' (minimum) apart. They shall be a
minimum of 6" and maximum of 24" in width. Wider
lines may be considered when, for example:
• Traffic speeds are above 35 MPH.
• There is no advance stop line.
• Drivers don't expect crosswalks.

Colored pavements alone are not considered a traffic
control device. Crosswalk lines must outline them.
For added visibility, mark the area inside the crosswalk
with white diagonal lines at a 45-degree angle.
These lines should be about 12"-24" wide and spaced
12"-60" apart. Use these diagonal lines on crosswalks at
unexpected areas, where many pedestrians are crossing
without any other traffic control device, and where
physical conditions make added visibility desirable.
Pedestrian crossing signs are also useful. Zebra stripes
(lines longitudinal to traffic flow) provide added visibility
and target value especially at roundabouts. See the
roundabout photo on page 6, for an example.

Railroad crossings
Special pavement markings are required before railroad
crossings with signals or automatic gates and at all
crossings where the prevailing speed of highway traffic
is 40 MPH or higher. Railroad
crossing pavement markings may be omitted in special
situations such as:
highway speed limit or prevailing speed is 35 MPH or
less and there are no active RR warning devices, or
• track is a minor spur where trains operate at 15 MPH
or less, or
• approach distance is less than 250' rural or 100' urban.
Pavement markings before a grade crossing are an
"X" with an "RR" behind them. A wide line is placed
above and below the "X". Identical markings must be
placed on each approach lane. All markings should be
white and reflectorized. Stop bars must extend from the
centerline to the edge of the pavement at 90 degrees to
the direction of travel. Place the W10-1 round RR warning
sign at the first cross line. A stop bar at railroad
tracks should be no closer than 25' from the nearest rail.

 

Pavement Marking Lines pt.1

Edgelines
Pavement edgeline markings give drivers a guide to the
edge of the pavement and also enhance safety. A study
of rural highways in Kansas showed that edgelines will
yield benefits exceeding their costs if an average of one
non-intersection crash occurs annually every 15.5 miles
of roadway. Edgelines are a particularly valuable visual
reference during bad weather and poor visibility, especially
along curves. They can also be used to mark the
pavement edge to reduce driving on paved or unpaved
shoulders. Break edgelines for intersections, major
driveways or interchanges. Continue edgelines through
minor driveways unless a full width turn lane has been
provided. Wide solid edgeline markings may be used
for greater emphasis.

Required (shall)
• Rural arterials 20' or more in width and 6000 vehicles
per day or more.
• Freeways and expressways.

Recommended (should)
• Rural arterials and collectors 20' or more in width
and 3000 vehicles per day or more.

Optional (may)
• Other paved streets based on engineering study.

Channelizing lines
Channelizing lines can be used to form channelizing
islands where traffic is going in the same direction on
either side of the island. They shall be a wide or double
wide solid white line. White diagonals or chevron marking
can be placed between the channelizing lines for
greater emphasis.

Yield lines
Yield lines are white and shall
consist of a row of solid white
isosceles triangles pointing
toward approaching traffic.
They are not required, but
may be helpful at roundabouts,
mid-block crosswalks, or other
locations with yield signs.

Stop lines
Stop lines are solid white lines and should be 12"-24"
wide. Stop lines emphasize the stop condition and
indicate where to stop. They are not required, but are
helpful in many situations. For example, visibility may
be better at a point closer to the intersection than the
stop sign can be placed. The stop line can be used to
show this to drivers. Stop lines should be a minimum of
4' in advance of a marked crosswalk. Do not use stop
lines with yield signs. Place no closer than 4' from the
nearest edge of the intersecting travel way and no more
than 30'.

Pavement Markings General Principles

General principles
Pavement markings should conform to the following general principles:

Color
Pavement markings must be yellow or white. Red and
blue are used in special cases:
• Yellow longitudinal lines separate traffic flowing
in opposite directions, or mark the left edge of the
pavement on one-way roadways.
• White longitudinal lines separate traffic flowing in
the same direction, or mark the right edge of the
pavement.
• Contrasting black marking placed next to a white
marking may be used to make the white line stand
out on light-colored pavements.
• Words and symbols, crosswalk and stop lines are
white.
• Red and blue are used in special cases. Blue is for
parking spaces for persons with disabilities; red for
raised pavement markings for roadways that shall not
be entered such as one-way streets or alleys.

Width
• Line width indicates the degree of emphasis. Normal
centerlines and edgelines are 4"-6" wide. A wide line
is at least twice the width of a normal line.

Number
• Double lines-two normal width lines separated by
a discernible space-indicate maximum restriction:
driving across them is prohibited.

Solid vs. broken
• Solid lines discourage crossing and should not be
crossed. Broken lines may be crossed.
• A broken line is formed of segments and gaps, usually
in the ratio of 1:3. For example, on rural roads a 10'
segment would be followed by a 30' gap.
• Dotted lines provide guidance and are generally
used as line extensions. They have noticeably shorter
segments: for example, a 2' line and a 2' to 6' gap.
A dotted line where a lane is dropped or added may
consist of a 3' line and a 9' or 12' gap. The marking
shall be the same color and width as the line it
extends. A normal-width line may be used to extend
a wide line through an intersection.

Pavement Markings Materials

Many materials can be used for pavement marking. The choice depends on cost, durability, retroreflectivity, pavement surface, and drying time.

Paint Water-based paint, applied either cold or hot, is the most commonly used pavement marking. It is low cost with a short drying time, but its visibility on wet nights is just moderate. Traffic and snow plowing wear it away in about a year. Oil-based (alkyd) paint, when used, must meet environmental air quality restrictions
on volatile organic compound (VOC) emissions.

Thermoplastics These pavement-marking materials are made of thermoplastic heated to about 400° F and spread onto the pavement surface. Glass beads to increase reflections can be spread on top, mixed in, or both. Thermoplastics have a long service life, good visibility, and good retroreflectivity. The no-track time is short, and cost is mid-range. Special application equipment is required.

Epoxy Also applied as a liquid with special equipment, epoxy has good visibility and retroreflectivity, and cost is moderate. No-track time is 5-20 minutes. Markings last 3 to 4 years.

Tapes Pre-formed tape can be either inlaid as part of new construction, or overlaid. It has excellent visibility and retroreflectivity and lasts 7-8 years, but is higher cost. Wet reflective tape has excellent wet night retroreflectivity with about a 4-year life. Cost is medium and durability is poor. Modifications are being made to produce a tape with both durability and wet night
retroreflective quality.

Markings that must be visible at night shall be retroreflective. In general this applies to all pavement markings except parking lines and curb markings. For paint, glass beads are mixed in or dropped on the markings while still wet. Durable products are made with reflecting materials. In pedestrian areas, marking materials should not create slipping or tripping hazards.

Raised pavement markers can be useful to supplement pavement marking, but cost is a factor, and they must be correctly installed. Wet reflective tape is another supplement option.

Pavement Markings

Pavement markings have important functions in providing guidance and information to drivers. In some cases they supplement
regulations or warnings given by other devices. In other cases they are used alone and produce results that cannot be obtained by any other device.

Pavement markings can also enhance safety. Centerlines have been shown to cut crash frequency by 29% compared to roads
without them. Marking types include not only pavement and curb marking but also object markers, delineators, colored pavements,
barricades, channelizing devices, and islands.

Pavement markings have limitations. They are obliterated by snow, may not be clearly visible when wet, and may not be very durable under heavy traffic. It may be necessary to refresh them every year or more often. Despite these limitations, pavement markings are still used because of their unique advantage: they convey information to drivers without diverting their attention from the road.

 

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Striping Parking Lot

How to square a parking lot before layout:

All of your measurements should relate to one line - your base line. Choose the placement of this line carefully. Maybe if you have a long straight curb, you can use this as your base line. If the parking lot serves a building, make sure that the parking spaces will be square and parallel to the building. Once you have a base line, you need to turn a line at 90 degrees to this line. Here's how we do it:

Once you have your base line, go ahead and lay out the ends of the parking spaces. In this case they are all at 9 foot intervals. Select a mark to use as your center mark, count an equal number of marks on either side, and use your long tape to draw an arc roughly at right angles to your base line. Snap a line from your center mark through the point where the arcs intersect. This line will be at 90 degrees from the base line. The longer the lines used, the more accurate the right angle will be.