To address current and future traffic demand , the Orange County Transportation Authority ( OCTA ), in partnership with the California Department of Transportation ( Caltrans ), is improving I - 5 from north of Interstate 405 ( I - 405 ) to State Route 55 ( SR - 55 ). OCTA and Caltrans are working with the neighboring cities of Irvine and Tustin .

OCTA ' s Focus on 55 program supports businesses along the SR - 55 ( I - 405 to I - 5 ) Project corridor during construction . The program offers marketing assistance to increase exposure for businesses and encourages customers to shop local .

Project Overview OCTA and Caltrans completed construction of a second carpool lane on I - 5 between SR - 55 and SR - 57 . The I - 5 / Main Street HOV on - and off - ramps were demolished to make room for the new lanes . The project reduces congestion , alleviates bottlenecks and improves traffic flow . Project Benefits Added a second carpool lane in both directions on I - 5 between SR - 55 and SR - 57 . Restriped ...

Work is expected to start this month on improvements to four miles of SR - 55 between I - 405 and I - 5 . The three - year , $ 475 . 1 million project will improve mobility and reduce congestion on the freeway , a vital link from central Orange County to the coast .

WHAT : The Orange County Transportation Authority , in coordination with Caltrans , is breaking ground on the SR - 55 Improvement Project between I - 5 and I - 405 , from the Santa Ana and Tustin areas to near Irvine and Costa Mesa .

Toll Schedules The 91 Express Lanes travel through portions of Orange and Riverside countries and toll charges vary .

The project extended a westbound lane from the northbound ( NB ) SR - 55 / westbound ( WB ) SR - 91 connector through the Tustin Avenue interchange . In addition , a westbound auxiliary lane from east of the NB SR - 55 / WB SR - 91 connector to the Tustin Avenue off - ramp was reconstructed .

Eligible Applicants Eligible applicants are limited to the 35 local government agencies in Orange County ( cities and County of Orange ). Eligible agencies must be able to receive federal funding through the California Department of Transportation ( Caltrans ) local assistance .

KEEPING ORANGE COUNTY MOVING The Orange County Transportation Authority is the county transportation planning commission , responsible for funding and implementing transit and capital projects for a balanced and sustainable transportation system that reflects the diverse travel needs of the county ’ s 34 cities and 3 . 2 million residents .