The $5.9 million Wai'anae Coast Emergency Access Route, years in the making, is finally completed.

The results are not pretty: Parts of the route are unpaved or prone to flooding, as the most recent rains demonstrated. It will only open during emergencies.

But this patchwork of public and private roads will allow residents to get from Makaha to Nanakuli and back without using Farrington Highway, which all too frequently is blocked by everything from water-main breaks to knocked-over power poles.

Certainly, it's about time. For years, residents have lived with the uncomfortable reality of being suddenly trapped on Farrington Highway with no way out or around. That's a dangerous situation in the face of a medical emergency or looming natural disaster.

And clearly it doesn't take much to shut down the only way in and out of the coast.

In fact, the initial plans for the route were launched in 2000, after a hostage standoff closed the highway in both directions for 14 hours.

And each year for past three years, accidents and inclement weather have shut down the highway for extended periods.

But the route itself is only one part of the solution. The ability of emergency workers to swiftly redirect traffic to the route will be critical. In the heat of a crisis, the process would go smoother if most local residents were already familiar with the route; a public-education campaign could be useful preparation.

Because if history is any guide, the route will eventually be put to the test.