State Route 55
The Costa Mesa Freeway, State Route 55 (SR-55), was originally constructed in 1962 as a four lane (two in each direction) highway. Within the next ten years one additional lane was added in each direction.
In 1985, Orange County's first carpool lane was added between the I-405 and the SR-91 freeway. The freeway was also extended to 19th Street in Costa Mesa in the late 80's.
With the help of Measure M, Orange County's half cent sales tax for transportation improvements, along with additional state and federal dollars, the face of the SR-55 continued to change.
In late 1995, the freeway was widened between the SR-22 and McFadden Avenue, with a direct carpool lane connector between the I-5 and SR-55.
From 1996 to 2002, Caltrans and OCTA completed the addition of one lane in each direction between the I-5 and the SR-91. Currently, the freeway has a total of five lanes in each direction including the carpool lane and provides enhanced traffic flow to more than 300,000 motorists traveling the freeway each day.