ASK US WHY
The Third recently received two questions about what the pros call pavement markings. It’s likely that you refer to it as road paint or simply, ‘the lines on the road’. One reader wants to know why these pavement markings don’t last a season and if CBRM is using the cheapest paint that it can find.
Another reader wants to know why, whether on a bike or on foot, some pavement markings are slippery when wet. They are also a little confused about why some of the wet paint isn’t slippery.
So, to get the answers The Third reached out to engineer Raymond Boudreau, who is the Senior Manager with CBRM’s Public Works.
Apparently, since 2009 payment markers aren’t what they used to be. That’s when the federal government created New environmental regulations which set limits on the concentration of volatile organic compounds (VOC) allowed in traffic paint. These new low VOC traffic paints are more challenging to work with and don’t work as well as the older solvent-based paints, which dry faster in colder conditions and adhere better to dirty or oily surfaces.
But Boudreau says that in addition to the almost fifteen-year-old regulations, there are a few reasons why the pavement markings on our roads wear quicker than the municipality wants.
“Our winter climate is a major factor,” says Boudreau. “The majority of the wear on our pavement markings takes place during the winter. Most of our centre line and lane line painting takes place on major arterial and collector roads. These roads see the most traffic and are maintained to bare pavement condition in the winter through plowing and salting operations. The paint simply can’t withstand snowplowing blades and the scouring effect of rock salt and studded winter tires.”
When asked if CBRM uses the cheapest paint they could find, it was a quick “no,” from Boudreau. However, he also let us know that Thirders aren’t always getting the highest quality paint available either. Economy, effectiveness, and efficiency also play important roles.
Between July 2017 and April 2018, CBRM evaluated the performance of several “high durability” pavement marking options.
Boudreau told The Third that as a result of the study, CBRM now utilizes “durable” pavement markings in select areas.
“These areas receive a two-part paint that forms a harder, more durable material,” said Boudreau. “Durable markings are significantly more expensive than traditional line paint and so they are only applied to the highest traffic arterial roads and some crosswalks to ensure cost-effectiveness. These areas tend to have more visible paint remaining on the road at the end of the winter season, which helps control traffic in the spring until temperatures warm up enough to apply fresh markings.”
Another contributing factor to our lane-less roads, said Boudreau, is our climate. Pavement
Markers can’t be applied when it’s cold.
“Since our weather doesn’t usually warm up enough to apply paint until late Spring, there is a period at the end of the winter before the lines can be re-painted [when] the markings are less visible than we would like.”
As for why the paint is slippery when wet. The paint itself seems to be the issue.
“When pavement markings are applied, they fill in any small holes or voids in the asphalt creating a smooth surface,” said Boudreau. “In dry conditions, these surfaces aren’t generally slippery, however during or directly after a rain, water can build up on the surface causing them to get slippery in wet weather.”