Shortly after 8 a.m. on a recent Tuesday, a semitruck stalled on the Ship Canal Bridge, heading south on Interstate 5.
About 10 minutes later and four miles north on I-5, a motorcycle and an SUV collided near Northgate.
Another 10 minutes or so after that, and seven miles farther north in Mountlake Terrace, a third collision in the southbound freeway lanes caused minor injuries.
All three incidents were cleared within minutes. But soon enough, traffic was backed up in Lynnwood, 13 miles north of the Ship Canal.
From the cab of his customized F-250 pickup, Ken Buretta, whose job is to clear such routine blockages, listened in on his CB radio and pondered the cascading congestion.
“Was that a backup from the Ship Canal?” Buretta wondered. “It’s at Northgate, now it’s at 220th (Street). They’re all five to 10 minutes apart, you’ve gotta wonder. Sometimes the first collision is nothing, it’s the guy coming up over the hill behind, then all of a sudden it’s backed way up there for no reason.
“It snowballs really quick.”
The highway through the Seattle region was originally designed as a toll road in 1954 to meet traffic volumes of the 1970s. It reached its capacity in the 1990s.
Nearly 100,000 more cars a day travel I-5’s busiest stretch, just south of the Ship Canal, than did 40 years ago, but the freeway is no bigger.
Earlier this year, a propane-truck crash on the freeway, just south of its junction with Interstate 90, spread gridlock for miles, crippling nearly every street in downtown Seattle.
That was an extreme case. But nearly any sort of blockage can wreak havoc on a roadway engorged with vehicles,…