These Spots on Hudson Valley Roads Are Not What You Think

You may have noticed an increase in stains on the public roadways in and around the Hudson Valley. They're probably not what you think they are.

A while back I was walking around my neighborhood and suddenly noticed stains all over the road. I guess they had never caught my attention before, but once I spotted the dark blemishes I began to see them everywhere.

The oddly-shaped stains began to grow in numbers just a few years after the roads in my neighborhood were repaved. I first chalked them up to leaking oil from the mail truck or perhaps stains from fallen acorns or other debris, but they never seemed to disappear and popped up at random places all over the roadway.

What Are These Stains All Over New York Roads?

After taking a closer look, I noticed that the dark stains were orange in color as if something was rusting right through the roadway. I thought that perhaps the issue was caused by pieces of snowplow that had chipped off over the winter, rusted and permanently stained the road.

Seizing the opportunity to use the macro setting on my iPhone, I got down on the ground and took an even closer look.

What I discovered at the center of each of these stains was rust that appeared to be coming up from under the pavement. The more I investigated the spots, the more I was able to see that there were actually pieces of metal that were embedded into the asphalt. My theory was that after years of exposure to the elements, these metal pieces had rusted from underneath and stained the roadway.

It turns out that my hypothesis was correct. Apparently, some towns' departments of transportation opt to use cheaper asphalt that has pieces of iron mixed in. The industry website, forconstructionpros.com, says that when towns allow too much iron ore or pyrite into hot mix asphalt, the resulting roadway will begin to degrade and stain.

Depending on the climate, rust spots can appear on these surfaces months or years after they've been laid after being exposed to snow, ice and the sun's ultraviolet rays. These rusting pieces of iron chip away from inside the asphalt and allow water to get underneath. When the water expands and contracts, cracks and even potholes can quickly develop.

Most home driveways should not have these stains. Reputable construction companies use a higher quality asphalt that does not contain iron aggregates. If your driveway does have rust stains, that could be a big problem. Simply sealing the driveway will only make things worse. In order to stop the rust from returning and your driveway from crumbling, you'll need to use special primers and coatings to prevent the metal from rusting in the first place.

So, the next time you're out walking on the roadway, look down and see how many of these rusty spots appear below your feet. It'll tell you the quality of the asphalt your town used to cover the road and give you a good idea of how long the surface will last before it starts to crumble.