It’s Time to Ditch Thermoplastic

The use of color in bike lanes in Portland has been a welcome addition to our bike network, but you don’t have to ride very far before you see the problem with using a layer of colored plastic (otherwise known as thermoplast or thermo-plastic) that is applied with intense heat to stick to the road surface.  Depending on wear and tear from vehicles and weather, it may not last a year before needing to apply a new layer.  The costs for thermoplastic are not insignificant.

In other lands, like the Netherlands, they actually use colored blacktop/concrete to get the job done.  The result is a smoother ride that lasts for many years.  Portland would save money on material and labor costs by not having to come back and apply color after paving, or years later to re-stripe.

Years back at a Traffic & Transportation class presentation, PBOT Director Tom Miller (then Mayor Adams’ chief-of-staff) mentioned there were hurdles to implementing this type of approach in the United States. I am curious if anyone knows if this is a MUTCD compliance issue, or if there just aren’t contractors and materials available locally to make it happen. I’d welcome any thoughts on using colored pavement and ditching colored thermoplastic in Portland.

Further reading: Using Color in Bike Infrastructure


  1. The worst thing about thermoplastic is the vertical component of it. Cyclists are encouraged to deflate their tires to avoid getting jarred by layers of thermoplastic stacked on top of each other at crosswalks and other roadway signage

    • Great point, Allan. This especially irks me on Broadway, where they have seemingly placed 2-3 layers of thermoplastic on the crosswalk lines. At the least, they could make sure any thermoplastic that crosses a bikeway should be no higher than 1/8 inch. I believe the 1996 Portland Bike Master Plan recommended this as a standard for all transitions of a vertical nature.

  2. I think our traffic operations folks like the flexibility of paint…. car parking now, bike lane later. Or vice-versa? Don’t think that’s ever happened in Eugene.
    But I have to agree, I would MUCH prefer colored pavement over thermoplastic and would hope we could move in that direction eventually.

  3. I believe the biggest hurdle for Portland to begin implementing this type of design is the fact that contractors don’t have the specialized equipment on hand and ready for bidding. With time, as more and more communities like this idea, the support will cause contractors to change their style as they realize they can make money from these designs without buying a large piece of equipment for a one-time use (even though we know it would be used MUCH more than just once, but they aren’t sure about that yet…)

  4. Colored pavement is also a great way to celebrate local materials (if they are available.)

    Bend, OR uses red asphalt, similar to the approach in the Netherlands. The material is locally sourced from a quarry with red volcanic rocks.

    (see a picture of it on a cycle track in this slideshow:
    and here in a bike lane:

    Regarding compliance with the MUTCD – it’s true that green coloring is easier to implement than other colors, though I’m not sure if applies to colored rock pavement. I doubt Bend had to get approval for all of their red bike lanes because they are so pervasive, which leads me to believe it’s purely a materials issue.

  5. Thermoplastic, if not done competently, can be really slippery. The city had to re-do the boxes on Clinton at 39th because you couldn’t put your foot down without sliding. And yes, if they laid down not a skim coat but a thick layer of asphalt, we’d believe they really meant it.