While you sleep, we sweep

Did you know that every night of the week while you snooze, members of SDOT’s Street Maintenance Night Crew are cleaning Seattle’s arterial streets? 

Arterials carry lots of traffic.  With lots of traffic comes lots of dirt, grit and pollutants. 

There are many reasons to clean our streets.  Obviously, it makes our neighborhoods look better, which is good for businesses and our quality of life.  Removing sand and other debris also makes our roads safer for everyone, especially people using bicycles.  Plus, it keeps our air cleaner and reduces flooding because there is less material to kick into the air or clog storm drains.

But did you know that street sweeping helps fish? 

It’s true.  The dirt we sweep off on our streets is very different from the dirt you sweep off your kitchen floor.  

As a car rolls along the road it drops tiny bits of pollution.  Eventually tires treads wear away and brake pads need to be replaced because they’re worn down.   Where does all that rubber and metal “disappear” to?   Much of it is deposited on the streets, along with polluting metals like zinc from tires and copper from brake pads.  A car’s exhaust also drops pollutants on the road.  

Multiply those little bits of pollution from each car by hundreds of thousands every day, and you have a significant water quality issue.  (Or as 80’s band Depeche Mode said, “Everything counts in large amounts.”)

sweeper truck

If these pollutants are left on the street, rain washes them into storm drains, and eventually into rivers and Puget Sound, where they affect water quality and can harm fish and plants.

In response to this issue, last year Seattle Public Utilities (the folks in charge of our water quality) partnered with SDOT to sweep an additional 250 miles of arterials every week.  In this cost-effective program to improve water quality, Seattle Public Utilities provides the water quality experts and the additional funding, while SDOT does the sweeping.

Now you know.  So tonight as we sweep, you can sleep — even more restfully than last night.