If you’ve been in Keene long enough, you remember the great Keene bypass debacle. Once upon a time, the N.H. Department of Transportation conceived a plan to help speed traffic along routes 12, 10, 9 and 101. This was not the original 1970s bypass project that resulted in the big “T” intersection of those highways and the overpass of West Street, controversial in its own right, but a later plan.

The plan put forth in the mid-1990s was by far the largest project the state had planned in our southwestern corner in decades. Despite the earlier project, traffic had become bottle-necked so badly in and around Keene that nearly everyone agreed the region’s top priority was to alleviate it. Starting in 1991, plans began for ways to ease the four highways that flow into the city.

Costing $66 million, it included a remaking of what is now the “T” intersection, a large cloverleaf exchange at Winchester Street, which would be dominated by an overpass to carry Route 12/101 traffic past the intersection, and a diversion of Route 12 coming north, from Route 32 in Swanzey to Optical Avenue in Keene. As befit such an ambitious plan, the state held hearings and planning sessions and informational meetings for several years. Like many aspects of government, it moved at a relative snail’s pace, taking almost a decade to plan and arrange, despite the urgency.

The Sentinel covered it all, and ran a series explaining the project and its repercussions.

Well, if you’ve driven along Route 101 or Winchester Street recently, perhaps you’ve noticed the distinct lack of an overpass/cloverleaf where the roads meet. And if you’ve been on Lower Main Street, maybe you noticed the lack of abandoned businesses forced to close after Optical Avenue/Marlboro Street became the southern gateway to the Elm City.

That’s because those parts of the project never happened. Instead, as construction was about to begin, several area residents suddenly took note of the decade-long project and objected, saying it was too big and would despoil wetlands and other natural scenery. So began a four-year fight between the state and several conservation groups, most notable locally the Concerned Cheshire Citizens. In 2004, the state relented to their demand to replace the overpass with a roundabout — what to any American would likely be called a rotary, but which traffic engineers insist is somehow different and better, perhaps because it’s British.

The diverting of Route 12 to Optical Avenue, which, we admit, we never fully understood the point of, was forgotten.

And … it’s pretty much all worked out. Keene is now awash in roundabouts and we’ve all gotten used to them. Traffic flows better than when it was a stoplight, though perhaps not as quickly as it would have with an overpass. The view of Mount Monadnock driving east on that stretch of Route 101, which was one of the rationales for bypassing an overpass, was preserved — at least until the rail trail bridge was put up across the highway. And millions of taxpayer dollars went unspent on the project, only to be spent on something else.

All of this is a roundabout — ha! — way of noting that we’re getting déjà vu vibes regarding the city’s yearslong effort to overhaul its zoning, particularly with an eye toward downtown uses. The project has consumed a lot of city staff time. Public informational sessions were held; hearings, too. It’s been written about at length and discussed on local radio.

And only now, when the entire plan is about to be voted on by the City Council, are objections sprouting up. Stonewall Farm has raised an issue regarding restrictions on solar installations. Others have also suddenly awakened to the reality that some major changes may be coming (along with lots of minor ones) in how property can be used in the city.

Any and all concerns should certainly be heard by the council. There may well be effects of the overhaul that the city’s planners haven’t foreseen, despite all their effort. And hopefully they will improve the result, as in the case of the bypass project.

Still, there were lots of opportunities to be heard before now. City staff practically begged people to participate and offer input on the plan. Any inconsistencies or detrimental aspects of the project ought to be changed before it becomes “law.” That’s why there’s this last opportunity to speak up.

We just hope the process doesn’t become derailed at what amounts to the last minute by someone complaining about issues that could have been addressed in the plan had they participated when asked.