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? Read More+
Thermoplastic is the most commonly-used material in US cities and is typically used for spot treatments, such as in bike boxes, conflict areas, or intersection crossing markings. Cities selected thermoplastic based on conversations with other peer cities, proven durability in conflict areas, relatively minimal traffic impacts during installation, availability of material, ease of installation, and ability to spot repair. The key point of criticism against thermoplastic was the increased difficulty of installation on concrete or older asphalt (requiring a primer) and the relatively high material cost. Materials that were less frequently used include MMA, epoxy, and water-based paint. Peer cities reported mixed results on the use of paint, due in part to climate and motor vehicle related wear. Both San Francisco, CA and Missoula, Mt MT reported use of paint on cycle tracks, both at conflict points and throughout the length of the corridor. San Francisco reported longevity of about 15 months for the corridor and 12 to 20 months at conflict points, based on ADT. Missoula reported significant paint deterioration at conflict points, but a longer lifetime outside of conflict areas. Minneapolis reported significant wear of less than one winter along shared motor vehicle/bicycle lanes when treated with standard latex paint.
(City of Minneapolis Department of Public Works Traffic and Parking Services Division. (2011). Hennepin Avenue Green Shared Lane Study.)
The use of epoxy and MMA-based materials were reported less frequently. Seattle, and Columbia, reported use of MMA-based materials while New York, Philadelphia and Boston, reported using epoxy-based products. Seattle and Columbia reported while the MMA product is more expensive, it has superior longevity at conflict points with high ADT (e.g., freeway entrance ramps) and remains highly visible, which is consistent with the spot vs. corridor application.
What are the challenges of application on asphalt vs. concrete? Read More+
Installation on concrete requires the additional step of applying a primer or sealant and introduces the increased possibility of improper installation and subsequent deterioration. Several peer cities including New York and Salt Lake City reported that applying colored pavement to concrete in poor condition will result in a treatment with a much shorter lifespan . Salt Lake City estimated a lifetime of six months on existing concrete vs. 4-5 years on new asphalt. Regardless of the concrete’s current state of repair, the presence of roadway grease, particulate, dust, dirt and other debris on either an asphalt or concrete roadway resulted in a poor quality installation (reported by Austin and Los Angeles). Several cities, including Chicago, New York and Los Angeles reported grinding or blasting concrete or asphalt roadways to increase the application’s longevity as part of surface preparation. (STV Incorporated, Penn State University and NYC Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
What contributed to your decision to use a specific material? Read More+
Factors contributing to a decision to use of specific materials typically include:
- Recommendations from peer cities that have previous experimentation history. Several cities reported getting advice from cities with a longer history of using colored applications Portland, and St. Petersburg, or reviewing available studies documenting the experience of peer cities like New York and Minneapolis. (City of Minneapolis Department of Public Works Traffic and Parking Services Division. (2011). Hennepin Avenue Green Shared Lane Study. STV Incorporated, Penn State University and NYC Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
- Considerations of city crew experience and available equipment.
- Current city policy on colored pavement in bikeways. Vendor demonstrations in several cities, like Washington D.C. and Los Angeles led to the adoption of a specific material.
- Cost led several cities, like San Francisco and Long Beach to express alternatives that may provide a cheaper long-term solution like colored pavement. (Mark Christoffels. (2010). Second Street Sharrows and Green Lane in the City of Long Beach, California.)
- Installation difficulty and traffic impacts led several cities, like Seattle to steer away from materials with longer dry time such as epoxy. Cities like New York, that don’t install epoxy in conflict areas did not report traffic related concerns.
What impact does weather make on colored pavement?
Read More+
Weather makes an impact on material selection, especially in cities with cold and snowy climates where salt, sand, and snowplows are frequently used. In cold climates, paint has a shorter than average life span, but correct installation of materials (such as recessed thermoplastic) can increase the material lifespan even in cold climates.
Peer cities like New York, Chicago and Ottawa recommended against the use of water-based paints and indicated that more durable pavement markings like thermoplastic, MMA or epoxy will provide better service over the treatment’s lifetime. (Green Shared Lane Study. STV Incorporated, Penn State University and NYC Department of Transportation. (2012). Red Bus Lane Treatment Evaluation.)
What are the benefits of installation by a contractor vs. city crew? Read More+
Many cities interviewed preferred installation by a city crew to keep costs low. Portland, reported using a contractor when colored pavement was installed as part of a larger capital project, but required maintenance is invariably performed by city crews. In several cities, like Philadelphia, agencies allowed the contractor to spec the material used to apply color, which could result in the use of multiple materials within a single roadway or bikeway network that have different installation and maintenance requirements.
Smaller agencies or agencies that lack experience with thermoplastic or other durable pavement marking installations almost always relied on a contractor for several reasons, including the initial expense of acquiring the necessary equipment for installation, uncertainty about the degree to which bikeways were likely to be colored in the future, or the expense of staff training. This was also the case in cities like Seattle, where the product in use requires personnel to wear specialized safety gear during installation.
What has led to successful installation? Read More+
Successful installation typically derives from staff training and expertise as well as careful design of the treatment. Where pavement quality was good, most cases of failed installation reported by peer cities were based on poor surface preparation and/or desire to proceed with the installation despite adverse climatic conditions, like excessive moisture. Many vendors are willing to provide training and guidance during initial product installation, which can reduce the changes of improper installation.
The color green used also plays a role in user satisfaction. Several cities, including Seattle, San Francisco, New York and Minneapolis, received feedback that early installations were too dark to provide optimal visibility. Planners these cities have reported anecdotally that bicyclists seem happier with the brighter colors that retain better visibility over time.
Do you plan to maintain or expand your colored treatments? Read More+
Most peer cities interviewed reported a commitment to maintaining colored bikeway applications. Cities like Phoenix, that have recently started testing colored pavement or that face budget constraints were less confident about their ability to expand their colored bikeway system. Experimentation with longer corridor treatments in Salt Lake City have led to a desire to change the approach to pavement coloration and mark conflict zones rather than corridors based on material durability and cost. All peer cities interviewed expressed a desire to maintaining their existing system before considering expansion.
Have you thought about long-term maintenance? Read More+
Many cities are considering long-term maintenance of colored pavement as part of the overall system cost, though peer cities with a single demonstration installation were less likely to consider these costs. Cities such as Austin, TX have experienced early deterioration of thermoplastic installation in some locations due to improper installation, poor pavement quality or preexisting oil and debris on the asphalt . (The City of Austin Bicycle Team. (2010). Effects of Colored Lane Markings on Bicyclist and Motorist Behavior at Conflict Areas.) The City plans to consider installing new asphalt prior to new colored thermoplastic installations.
Several cities, like Missoula recommended that the cost for colored pavement be taken into account at all stages of the bikeway network development process, from master planning through implementation and development of public works budgeting (if this process is not already in place).