Colored Pavement Material Guidance

Description

Colored pavement can be utilized either as a corridor treatment along the length of a bike lane or cycle track, or in limited locations as a spot treatment, such as a bike box, conflict area, or intersection crossing marking. Colored pavement for use within bikeways treatments may take the form of an overlay, when the colored material is placed on top of the pavement or embedded, when the colored material is mixed into the pavement.

Overlay:

Paint, sometimes with additives such as reflective glass beads for retro reflectivity and sand for skid resistance, is the most widely used method to mark road surfaces. Paint is considered a non-durable pavement marking, is easily worn by vehicle tires and the elements in snowy winter climates, and often requires annual reapplication. Paint is the least expensive of the overlay materials.

Durable Liquid Pavement Markings (DLPM) include epoxy and Methyl Methacrylate (MMA). Epoxies are adhesive, waterborne acrylics that are typically applied as a paint or spray. MMA are 2-part liquids comprised of a resin and activator. While both coatings can be skid resistant, retro reflective and can adhere to concrete or asphalt surfaces, epoxies are sensitive to moisture and temperature and may require long dry times. MMA may be installed at any temperature, is durable and dries quickly, but is more expensive than epoxy.

Thermoplastic, another type of durable pavement marking, is a type of plastic made from polymer resins that becomes a homogenized liquid when heated and hard when cooled. Thermoplastic can be pre-formed in specific shapes, such as tiles that can be assembled like a puzzle to color bicycle facilities. Thermoplastic can also be used for bicycle lane symbols, arrows, pavement legends and shared lane markings.

Thermoplastic tends to last longer than epoxy and is easier to apply then MMA. Retro reflective and anti-skid materials can be applied or mixed throughout the plastic.

Embedded:

Colored asphalt is composed of the same material as standard asphalt, but has a colored pigment added. The colored asphalt may be installed as a thin layer over conventional asphalt to reduce cost. One well-known use of colored asphalt is Bend, Oregon’s red bike lanes, which utilize a localized red pigment in the colored asphalt. The tinted asphalt was applied over fresh black asphalt before the year 2000 and has worn well with regular street sweeping and maintenance, but has faded over time. Green pigment options are available.

Previous Experimentation and the History of Color Application in North America

Cities in North America have been experimenting with the application of colored pavement, primarily to highlight bicycle motor vehicle conflict areas since the mid 1990’s, the application of color to an entire corridor is a more recent practice. Between 1997 and 1999, the City of Portland, with support from the Federal Highway Administration (FHWA), conducted an experiment in which 10 conflict areas were marked with blue paint or thermoplastic and accompanying signing. (City of Portland Office of Transportation. (1999). Portland’s Blue Bike Lanes., US Department of Transportation. (2000). Evaluation of Blue Bike Lane Treatment used in Bicycle-Motor Vehicle Conflict Areas in Portland, Oregon.)

The study results demonstrated that thermoplastic was more durable than paint, which disappeared after the first winter season. The experiment reported positive results for decreased cyclist and motor vehicle driver conflicts at the ten study sites, but the treatments applied were less visible than desired in low light conditions.
Subsequent to Portland’s blue bike lane experiment, the FHWA approved interim experiments utilizing green colored pavement in communities across the US including Chicago (IL), New York (NY), St. Petersburg (FL), San Francisco (CA), Columbia (MO), Long Beach (CA), Austin (TX), Nashville (TN), Missoula (MT), Golden (CO), the Minnesota Department of Transportation (for Minneapolis), and the Pennsylvania Department of Transportation. (University of North Carolina Highway Safety Research Center. (2008). Evaluation of a Green Bike Lane Weaving Area in St. Petersburg, Florida.)

Green was selected over blue or red because in the US blue roadway markings are reserved to designate accessibility parking while red markers are sometimes used to alert motorists of wrong way driving. Interim approval for the optional use of green pavement for bike lanes was granted on April 15, 2011.

Treatment Application Summary

Material Type Pros Cons
Paint
Recommended for temporary, pilot, or experimental spot treatments.
Easy application and moderate dry time. Proven to wear quickly in areas with moderate to heavy motor vehicle traffic.
DLPM
MMA is more appropriate for spot treatments than epoxy.
Material is durable if installed according to manufacturer specifications.
MMA has quick dry times and good durability.
Epoxy can have long dry times, causing increased disruption to roadway traffic.
Requires special installation equipment.
Thermoplastic
Recommended for spot treatments.
Ideal for intersection treatments and other high-traffic conflict areas.
Quick cure time minimizes traffic impact.
Relatively low-cost equipment investment.
Easy spot maintenance.
Shown to wear well in conflict areas.
May be cost-prohibitive for large scale applications.
Colored Asphalt
Recommended for Corridor treatments.
Not recommended due to complexity of paving operations. Spot maintenance is difficult and may result of color loss when trenching occurs.
Requires equipment and expertise to install.
What has led to successful installation?
Staff training and expertise as well as careful design of the treatment have resulted in successful installations in North America cities abroad. Where pavement quality was good, most cases of failed installation reported were due to poor surface preparation and/or a desire to expedite the installation. (New York City Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
Material Type Pros Cons
Paint
Recommended for corridor treatments. Ideal for protected bicycle facilities like cycle tracks.
Cost-effective along corridors with low or no motor vehicle traffic impacts. Can be slick when wet. Not durable in high wear locations.
DLPM
Recommended for corridor treatment.
Materials are long-lasting and can be cheaper than thermoplastic. Requires special installation equipment
Thermoplastic
Not recommended for long corridors due to cost.
Material is known to have long life and good performance qualities in the US and Europe. Cost-prohibitive in corridor applications.
Colored Asphalt
Recommended for corridor treatments.
Long lasting treatment.
Should be coupled with initial construction or repaving for cost savings.
Has same lifespan of standard asphalt.
Proven long-term use as an effective treatment in Europe.
Requires little maintenance.
Requires cleaning of machinery or maintenance of special machinery for colored applications. 

Colored asphalt is not retroreflective by itself; in the Netherlands a white thermoplastic stripe is used for visibility. (Peter Furth. (2012). Red Asphalt Pavement.)

Can require special attention at joints between colored and standard asphalt.

What has led to successful installation?
Many cities prefer to have a city crew install coloration to reduce cost when possible though a contractor may be cheaper when installation requires special equipment. Some cities used a contractor when colored pavement was installed as part of a larger capital project, when city staff do not have the training, or when liability may be a concern.

 

Material Attributes

Paint
Composition Pigment and binder, glass beads and/or a fine aggregate can be added for retroreflectivity and skid resistance.
Surface Preparation Pavement should be free of dirt, dust and moisture.
Installation Temperature Pavement and air temperature should be at least 40 degrees Fahrenheit.(Wisconsin Department of Transportation. (2011). Construction and Materials Manual.)
Installation Considerations Most paints can be applied immediately to new asphalt or concrete.
Primer is not required on concrete roadways.
Paint dry time depends on ambient temperature. (Iowa State University Institute for Transportation. (2001). Iowa Traffic Control Devices and Pavement Markings: A Manual for Cities and Counties.)
Maintenance Considerations Spot maintenance requires a simple reapplication of paint.
Material Cost 

(Costs vary depending on size of application, and whether city crews or contractors perform)

$0.6 Sq. Ft. for raw materials, $1.20 – $1.60 Sq. Ft. installed.
Longevity Six months to two years based on weather, motor vehicle traffic and snow removal operations (if applicable).
Availability Widely available in North America.
Skid Resistance and Retroreflectivity Glass beads may be added to paint for retroreflectivity and sand added for skid resistance.
Peer City Experience Several cities have reported satisfactory performance in corridors without motor vehicle wear.
Durable Liquid Pavement Markings (Epoxy and MMA)
Composition Epoxy – epoxy/resin.
MMA – acrylic-based resin.
Surface Preparation Pavement should be free of dirt, old pavement markings, dust, and moisture. Poor asphalt quality can significantly shorten the lifetime of a treatment. Presence of oil may result in failure to bond to roadway surface. Installation of MMA on concrete requires shot blasting and priming. (New York City Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
Installation Temperature Most epoxies require air and substrate temperatures of at least 40 degrees Fahrenheit. MMAs may be installed at almost any temperature. (Flint Trading. (2010). Ride-A-Way TM. Specification Colorized Coatings.)
Installation Considerations Installation generally requires special equipment.
Epoxy dry time increases as temperature decreases. Dry time is measured in hours. (Flint Trading. (2010). Ride-A-Way TM. Specification Colorized Coatings.)
MMA dries in about one hour. (Stirling Lloyd. (2008). Safe Track SC Application Guidelines.)
Maintenance Considerations Some cities have reported that epoxy color intensity fades over time due to color instability under ultraviolet lighting (sunlight) exposure. Pooling water can reduce material longevity. (New York City Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
Material Cost 

(Costs vary depending on size of application, and whether city crews or contractors perform)

Epoxy: $1 – $3 Sq. Ft. for raw materials. $8-11 Sq. Ft. installed.
MMA: $3 – 4 Sq. Ft. for raw materials. $8-11 Sq. Ft. installed.
Longevity Similar to thermoplastic. Poor pavement quality impacts treatment longevity.
Availability Epoxy currently has wider US availability than MMA.
Skid Resistance and Retroreflectivity Material can be skid resistant and retro reflective.
Peer City Experience Epoxy paint used in peer cities has proven skid resistance and longevity of 3 – 5 years. MMA may last as long as 3-6 years.
Thermoplastic
Composition Polymer resin, pigment, glass beads, and filler.
Surface Preparation Pavement should be free of dirt, dust, and moisture. Typical preparation consists of street sweeping and then brushing.
Installation Temperature Some (but not all) thermoplastic requires that pavement and air temperature be 50 to 55 degrees Fahrenheit for most materials to bond properly. (Washington State Department of Transportation. (2007) Maintenance Manual.) Most thermoplastics should be heated to 400 – 450 degrees Fahrenheit.
Installation Considerations Many thermoplastics can be applied immediately to new asphalt, but new concrete must cure at least 30 or longer days prior to installation. (Texas Transportation Institute. (2003). Effective Pavement Marking Materials and Applications for Portland Cement Concrete Roadways.) Primer is typically required for application to concrete roadways and may assist with adherence on older asphalt surfaces. Cure time is measured in minutes.
Maintenance Considerations Spot fixes are simple: a small piece of plastic is torched into place.
Thermoplastic can be recessed to make edge flush with pavement or tamped down to form a seal with the roadway to reduce likelihood of snow plow impact.
Material Cost 

(Costs vary depending on size of application, and whether city crews or contractors perform)

$3 – $6 Sq. Ft. for raw materials, $10 – $14 Sq. Ft installed.
Longevity Average of 5 years, or 3 times the lifetime of paint under the same conditions. Many installations have lasted significantly longer. Poor initial pavement quality shortens lifespan. (New York City Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
Availability Widely available in the U.S. Vendors are willing to provide training on installation.
Skid Resistance and Retroreflectivity Material can be skid resistant and retroreflective. Most effective materials will mix corundum and beads throughout materials rather than top coating material.
Peer City Experience Most common material used for colored bikeways in North America. Many treatments are too new to report long-term results. Cities with a longer history of use (such as Portland) report positively on durability, skid resistance, and maintenance.
Colored Pavement
Composition Bituminous pitch, sand/gravel, and pigment.
Surface Preparation Preparation for installation is the same for colored and standard asphalt. A base course is placed on an aggregate base heated to insure adhesion between layers.(Minnesota Asphalt Pavement Association. (Undated). Asphalt Paving Design Guide.)
Installation Temperature Standard paving considerations apply.
Installation Considerations Standard paving considerations apply.
Maintenance Considerations It is expected that colored asphalt at least 1 cm thick will last for the life of the pavement.
Material Cost 

(Costs vary depending on size of application, and whether city crews or contractors perform)

More expensive than standard asphalt installation based on cost of pigment. When applied as a thin top layer within new construction, pigmented asphalt costs between 30 and 50 percent more than a non-colored structural asphalt section. For thin overlay applications, the difference in cost will be greater. (Peter Furth. (2012). Red Asphalt Pavement.)
Longevity Based on motor vehicle traffic, but typically similar to conventional asphalt.
Availability Available in the US.
Skid Resistance and Retroreflectivity Skid resistance equal to uncolored asphalt. Asphalt is not retroreflective.
Peer City Experience Embedded colored pavement is used in few North American cities but many have expressed interest for longer corridor installations.

 

The European Experience

Many European countries commonly use color in bikeways, but the color chosen and the material used varies widely. European countries with the most extensive bikeway color tradition are the Netherlands and Denmark. In the Netherlands, colored asphalt or colored concrete pavers are used for most applications. Colored asphalt is an economical treatment that provides permanent color, durability, skid resistance and is well-suited to the Dutch practice of coloring bikeways along their entire length. It should be noted that the Dutch choice of red for bikeways lends itself to the use of colored asphalt for two reasons: 1) the coloring agent can be successfully applied to either black bitumen or clear bitumen (as opposed to other colors, which can only be implemented with the more expensive clear bitumen), and 2) naturally red-colored rock can be used for the aggregate agent. In Denmark, France, Luxembourg and Germany, bikeway coloring strategies vary, but are generally applied as spot treatments (as opposed to coloring the entire facility). Thermoplastic and epoxy (also known as cold plastic in Europe) are the preferred medium for applying intersection spot treatment bikeway color in many European countries.

Peer City Experience

21 North American peer cities where colored pavement is in use, or where installations are planned for the near future, were interviewed to determine the state of the practice. Interviewees represented a range of regions, climates, sizes, and levels of experiences with colored pavement. The interviews resulted in several common themes, including:

  • Generally positive response to colored pavement from both bicyclists and motor vehicle drivers.
  • There is a need to further improve technical expertise for installing and maintaining colored pavement.
  • Thermoplastic is the most commonly used material and spot applications are the most frequent type of installation.
  • Green will be brighter at installation and material should be allowed to settle and wear prior to judging color satisfaction.

Frequently Asked Questions

The experience applying colored bicycle facilities in the United States is evolving rapidly. Experiences with material selection, application techniques, and the impact of climatic factors are being collected in many of the US cities that have been experimenting with colored pavement. This experience in many cases has not been easily accessible by agencies looking to develop colored bicycle facilities. Twenty-one US Cities were interviewed to improve the accessibility of information regarding the range of experience with the application of colored bicycle facilities. The following frequently asked questions address many of the common questions agencies have when considering the development of colored bicycle facilities.

What material is most commonly used?

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What are the challenges of application on asphalt vs. concrete?

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What contributed to your decision to use a specific material?

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What impact does weather make on colored pavement?

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What are the benefits of installation by a contractor vs. city crew?

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What has led to successful installation?

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Do you plan to maintain or expand your colored treatments?

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Have you thought about long-term maintenance?

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