In this sluggish economy, and amid all the clamoring for jobs and housing, the state’s decision to reclassify 576 acres of prime agricultural land to make way for the mammoth Koa Ridge development probably could have been anticipated.

But that doesn’t make Thursday’s decision by the Land Use Commission any less consequential. It would connect the patches of development sprawl between Waipahu and Mililani, adding 3,500 homes to the suburban mix.

The impact on rush-hour traffic, according to developers Castle & Cooke Homes would be relatively moderate. Traffic studies indicate that the subdivision would add only five minutes to commuting time. Convincing all the Central Oahu drivers who now do battle at the H-1/H-2 interchange of that assertion will be a tough sell, as the project proceeds for rezoning and further permit approvals from the city.

The LUC will meet Oct. 15 to issue its written order, which is expected to set conditions. That should provide an opening for the commission to offset some of the impact on traffic and the loss of farm land, two of the principal negatives posed by such a large development in an already congested corridor.

Commissioners should take the opportunity to insist on a link of some sort with the city’s planned fixed-rail system that will come through to the south. The provision of a busway or other accommodation is far easier if developers plan for them at the front end.

As for the continued whittling of Oahu’s agricultural district: It would be wise for the state to insist on the protection of agricultural parcels to compensate for the loss of the Koa Ridge site. Castle & Cooke has pledged to lease about 667 acres of its land in Wahiawa for a 10-year term with a five-year extension option. That lease would go to Aloun Farms, which now grows vegetables and seed corn on part of the Koa Ridge land. Considering the top-grade quality of the soil that will be lost to farming, Castle & Cooke surely should be pressed to commit to longer-term security for the farmers.

Castle & Cooke contends that Koa Ridge offers a more forward-looking approach to growth, with more walkable neighborhoods and a better mix of homes and employment centers. For every three homes there, planners say, two jobs will be created.

That sounds promising. Certainly the addition of a hospital at Koa Ridge, along with modest hotel accommodations attached to it, sound like new regional assets.

But those arguments duck several important questions. What kind of jobs will be created? Will these workers be able to afford living at Koa Ridge, or will homeowners and renters be forced to hit the road for town or Kapolei? How will the new hospital affect the operations of existing health-care institutions that are already struggling in a difficult economic environment?

The state panel on Oct. 15, and the city Planning Commission to follow, need to make sure this development, already facing criticism from dubious Central Oahu residents, is a net improvement for all, not just for the landowners who stand to make a sizable profit.