It was bound to happen at some point, but commuters can celebrate the fact that it’s happening now. The H-1 freeway Zipper Lane, largely a success story over the past 18 years, needs more room to accommodate all its users.

It will be getting that capacity boost in time for the yearly “Back to School Jam.” Starting at some point in August, the state Department of Transportation promises to widen the contraflow area enough to fit two traffic lanes instead of one.

The morning commuter lane, now open 5:30-8:30 a.m. weekdays between Waipahu and Kalihi, also will stay open for a half-hour later, a move that officials hope will accommodate up to 1,700 additional vehicles per hour.

This serves as a prime example of the multipronged approach Oahu will require if its transportation system is to function tolerably in the coming decades.

Billions are being spent on a rail system that will be a necessary alternative conduit for the densely populated urban corridor con-necting West Oahu with Honolulu.

But city and state authorities can’t ignore improvements to the freeway system, which will remain as a backbone connecting communities as well as linking them to mass transit.

The state Department of Transportation is spending up to $3.5 million on the Zipper Lane expansion, widening the space between the retractable “zipper” barriers by 2-1/2 feet.

The remaining space will accommodate the same number of regular traffic lanes.

That’s a more cost-effective way to improve its performance than to add lanes through more conventional freeway expansion or double-decking the freeway.

There are other relatively quick and simple traffic-management fixes under way, according to the DOT:

>> An afternoon contraflow is being added to Farrington Highway through its most congested stretch in the Nanakuli area. This is also pegged to start in August, said DOT spokesman Tim Sakahara.

The change is meant as a temporary fix until the highway is widened in that area to accommodate turning lanes and easing traffic flow, he said.

>> Tow trucks will be staged along Farrington to keep the lanes clear in a more timely way.

>> The shoulder lane running between the Aiea Heights overpass and the Pearl City exit will have expanded hours, also later this summer. Now open between 3:30 and 6 p.m., the new hours will be 3-7 p.m, he said.

>> A new shoulder lane in the eastbound direction is being planned to open for the new school year as well to ease the morning rush. This one will serve traffic along Kualakai Parkway for Kapolei commuters traveling toward Honolulu.

The public needs assurances, however, that the potential for glitches has been thought through. It’s only been a little more than a year since the “carmageddon” episode in which the “Zipmobile” that opens and closes the commuter lane broke down, and parts needed to fix the system were lacking.

Sakahara said both Zipmobiles are being completely refurbished, with staff on-island able to make any needed fixes to what had been a proprietary computerized system.

That’s good news. There are costlier, longer-term projects in the construction pipeline for H-1, including a widening of the eastbound side of the freeway in Pearl City. But if these incremental changes do prove effective and problem-free, they could be replicated in other trouble spots.

Ed Sniffen, DOT Highways Division deputy director, rightly observed that freeway fixes can’t by themselves remedy the island’s congestion woes.

On Oahu, the community has wisely authorized the construction of a rail system as the most efficient means of moving more people rapidly where they need to go. That system, as a part of a whole range of improvements, is crucially needed.

The implementation of rail has been criticized — justifiably — but in the end the project will yield a better solution than double- decked freeways, one that can make the Oahu commute easier to bear.