West O'ahu motorists traveling on H-1 Freeway between Kunia and Makakilo soon will no longer need to take a loopy bypass.

Reconstruction of the two bridges at what will be the future North-South Road Interchange is expected to be completed and ready for traffic by Christmas week, allowing those traveling through the area a straighter route, state Department of Transportation spokeswoman Tammy Mori said Friday.

Weather permitting, the switch back to the permanent route is scheduled to take place the nights of Dec. 22 and 23, with one side opening the first night and the other side the second night, Mori said.

Transportation officials began rerouting the traffic in June to allow for construction of the bridges, part of the $143 million North-South Road Interchange project. Vehicles in both directions have been required to take a detour along what will be the future off-ramps and on-ramps of the interchange.

The six-month detour has been the largest diversion of O'ahu's freeway system in its five-decade history but, despite initial anxieties, has gone off without a hitch, and the project is on schedule.

The speed limit in that section of the freeway, usually 60 mph, will stay at 50 mph pending completion of the interchange project, Mori said.

The ramps themselves will open for business next fall, coinciding with the opening of the northern portion of North-South Road, which would connect with Farrington Highway, she said.

North-South Road, also a state project, is expected to act as a six-lane reliever for traffic coming in and out of the heavily congested Fort Weaver Road for beleaguered 'Ewa motorists. Traffic is so bad that many travel several miles west into Kapolei to use that interchange in order to head east into Honolulu.

A future section of North-South Road extending south and connecting into Kapolei Parkway in 'Ewa Villages is expected to open in early 2010, Mori said.

Farther into the future, the North-South Road and the interchange are expected to one day connect on the north side with Makakilo Drive, providing an alternate route for Makakilo residents. The city is looking into different scenarios.