Location map of the Terwilliger curves
The "Terwilliger curves" is the name given to a 1.7-mile (2.7 km), six-lane section of Interstate 5 (I-5) in Portland, Oregon, known as one of the most dangerous stretches of highway in the state. Named for its physical characteristics and proximity to Terwilliger Boulevard, it first opened in 1961 and soon became known for its high crash rate. Several upgrades, a reduction in the speed limit, and increased efforts to enforce traffic laws have had some success improving safety over the years, although crashes remain common.