Interstate 405 (I-405)


Tukwila, WA to Lynnwood, WA — Seattle Eastside Corridor

Interstate 405

Tukwila, WA to Lynnwood, WA — Seattle Eastside Corridor

Interstate 405 runs 31 miles along the eastern side of Seattle through Renton, Bellevue, Kirkland, and Bothell before reaching Lynnwood. Despite its short length, I-405 carries enormous traffic volumes as the primary north-south alternative to I-5 for the Seattle metro's Eastside tech corridor. Hills, curves, complex interchanges with I-90 and SR-520, and extreme congestion create a high-risk environment for commercial vehicles. Rain-slicked roads, distracted tech-sector drivers, and speed variability from stop-and-go to 70 mph in short stretches compound the inherent geometric challenges.

Length
31 miles
Risk Rating
HIGH
Risk Factors
Extreme traffic density in tech corridor Hills and curves limiting sight distances Complex I-90/I-405 and SR-520/I-405 interchanges Rain-slicked pavement year-round High speed variability (stop-and-go to 70 mph) Distracted driving in high-smartphone-use commuter population
Notorious Segments
  • I-405/I-90 interchange (Renton)
  • SR-520/I-405 interchange (Bellevue)
  • Renton S-curves
Connected Hubs
Regions
United States West Washington