What’s not to like about the city’s first Residential Parking Zone, established just off the Likelike Highway in Kalihi? For the residents undergoing the test of the new regulation, on a strip between the highway and Jennie Street, it’s all good.

However, that’s not an adequate measure of success. The city has to justify why these zones represent a general improvement for the public, and the preferences of the residents within the zone are an insufficient reason for new parking restrictions.

Based on the early feedback from Department of Transportation Services, officials are aware of the potential for the program, with possible downsides, to snowball.

DTS must keep the bar set fairly high, ensuring that the restriction is the only practical solution in a specific neighborhood that wants its own zone.

In April, the department conducted a pilot project in the narrow Wilson Tract. The aim was to test the notion of allowing overnight restrictions of parking in the Kalihi Valley neighborhood.

Permits are being issued to residents of the new RPZ — two resident and two guest permits per household. Starting June 1, they uniquely will be allowed to park on designated streets between 6 p.m. and 6 a.m. daily.

Because the pilot project drew such an enthusiastic response, the permanent zone will extend across the Likelike to include the Kula Kolea neighborhood. Both that area and the Wilson Tract share the same problematic characteristic: They are self-contained “islands” of houses disconnected from other subdivisions.

The parking crunch arose long ago, and the campaign to find relief for residents has been raised at neighborhood board meetings and pursued by elected representatives as well, said Jon Nouchi, the deputy director of DTS. It originated when residents of Kalihi Valley Homes, not being served by that public housing project’s limited parking facilities, started parking instead in the neighboring subdivisions.

“There really was no other alternative for the neighborhood,” Nouchi said.

That may be true, but any RPZ must be considered a narrow exception to the firm rule of open access.

Additionally, alternative solutions should be pursued. The state’s Hawaii Public Housing Authority must explore the potential to expand parking capacity on the Kalihi Valley Homes premises, now that the spillover no longer will be permitted.

Nouchi acknowledged that the conflicts exist around the island, particularly in neighborhoods built at a time when the number of cars per household was far lower.

“We’ve had requests for this for a long time from Manoa, but it’s hard to say that residents should be able to restrict parking there,” he said. “Every street is a public right of way. In Manoa, it is a competition between the residents and the University of Hawaii, which is a big piece of Manoa’s fabric.”

Nouchi is correct, and there are other older areas where the intersect of residences and businesses means the parking resource must be shared. Kapahulu and Kaimuki come to mind. And there are frequent occasions where short-term demand for parking — such as events around the Waikiki Shell and Kapiolani Park — must be accommodated.

The city has indicated the RPZ permits are being issued free for now but that a nominal fee may be charged if administrative costs make it necessary.

Officials should consider making the fees more like a rental charge, because that is essentially what they are. The city streets are maintained by the taxpayer, because they’re meant to be accessible to the public at large.

If this program is allowed to expand significantly, it’s not fair to the taxpayer that the public streets be conveyed to a private purpose, without adequately compensating the people who are paying to keep them in good condition.