8. Seattle
Credit: Aaron Morris / Getty Images

Inrix pegs I-5 as the most clogged road in Seattle, and it's obvious why: The highway runs north-south through the heart of the city. Seattle drivers spent an average of 37 hours in traffic in 2013, many of which were surely concentrated on a the stretch of I-5 north of the city between Shoreline and Queen Anne. 

Worst Corridor: I-5 between North 130th Street and Union Street. 

Worst Hour: Fridays at 4 p.m.

Travel Tip: Since most of the traffic is in the suburbs just north of the city, try swapping I-5 for Route 99 which runs almost parallel into downtown.