In an attempt to break the logjam on the H-1 through Makiki, workers will re-stripe parts of the freeway to create a fourth lane in each direction.
The $200,000 project was to begin Monday night and is expected to be completed before classes open at private schools and the University of Hawaii in late August. Public schools reopen at the end of this month.
The re-striping work will be done only at night and is expected to be completed by the first week of August, weather permitting, said Caroline Sluyter, state Transportation Department spokeswoman.
Sluyter said the state will re-stripe the freeway lanes in the Ewa-bound direction between Punahou Street and Pali Highway (1.4 miles) and Koko Head-bound between Ward Avenue and Keeaumoku Street (0.7 miles).
The three existing through lanes will be narrowed to 10 feet from 12 to create a fourth lane.
Sluyter said the work will be done from 10 p.m. Fridays until 6 a.m. Saturdays, 10 p.m. Saturdays to 6 a.m. Sundays, and 9 p.m. until 4 a.m. on other days of the week. Two lanes will be closed in each direction to complete shoulder and re-striping work.
State transportation planners estimate that on average 148,700 cars per day travel through that corridor near the Lunalilo onramp.
Westbound traffic entering the freeway at Lunalilo runs into traffic leaving the freeway at Vineyard, often creating a logjam because few drivers leave enough space in front of them for a smooth lane swap.
The state rejected a concrete "flyover" ramp for cars leaving the freeway at Vineyard as advocated by area legislators and some residents. Sluyter has said a 2010 study estimated that it would cost $85 million to build a flyover ramp.
"This is a low-cost solution to increase the capacity in the corridor that can be implemented quickly," she said.
Currently, to reduce the backup, traffic barriers are put up to prevent cars from entering the freeway at Lunalilo Street during the morning rush hour. Those diverted cars instead enter the freeway via the Pali onramp.
The barriers at the Lunalilo onramp would be phased out after the fourth lane is added.
The speed limit also will be lowered to 45mph, the department added.
The freeway would have 2- to 3-foot-wide shoulders through the effected sections, down from 4feet.
The state said the narrower lanes should not hinder operations of TheBus since buses already use 10-foot-wide lanes elsewhere on the H-1 and Middle Street.
The state said a similar re-striping project narrowed the eastbound H-1 lanes between the Liliha Street onramp and the Pali Highway offramp, creating a fourth merge lane.
If the fourth lane reduces westbound traffic jams, the state is looking at extending it from Pali Highway to Middle Street.
Two alternatives — ramp metering and widening the elevated viaduct along Lunalilo Street — were studied and rejected, the Transportation Department said.
