Dig they must, and now they are. The long-waited-for major improvement of Route 347 begins tomorrow. It will inevitably cause some inconvenience in the short term, but this key artery for northeastern Suffolk really needs fixing, and it's encouraging that the moment is here.

The former farm-to-market road could have become an extension of the Northern State Parkway, to serve booming northern Brookhaven. But it didn't. Instead, traffic-clogging retail sprouted all along 347. It's too late to go back and make it a limited access road. But the state Department of Transportation did a greenway design: more lanes, but friendlier to bikers and walkers. Later stages will vastly improve two major intersections, Route 25 and Nicolls Road. Overall, the project will improve travel, but no amount of building can totally eliminate rush-hour delays.

Work starts tomorrow on the piece from the Route 347-454 split in Hauppauge to just east of Route 111. This stretch of roughly a mile won't be done until 2012. And, given the state's fiscal situation, the whole 15-mile project won't be finished before 2020, says Subi Chakraborti, the DOT regional director. That seems like a lifetime away, but a start is a start.

In the first section, now mostly ugly, green touches will be obvious, including a "rain garden," to handle storm water runoff and provide some beauty. So, even as we grumble about lane closings, let's think green thoughts of better commuting ahead and rejoice that this work is finally under way. hN