When the state Department of Transportation opens a nine-mile arc of Interstate 540 on the northeast side of town, Raleigh will have a new east-west bypass.

And when will that be? Local commuters and shoppers want to know -- and so do travelers who see Raleigh as an obstacle rather than a destination.

Probably not by Dec. 31, as DOT had hoped. More likely in early 2007.

All six lanes are ready to carry traffic from Triangle Town Center in North Raleigh to the U.S. 64/264 bypass in Knightdale. But construction progress was set back by November's nine inches of rain. Some paving is still under way for a few on-off ramps at Buffaloe Road and U.S. 1.

DOT engineers decided against opening parts of I-540 before all lanes and ramps are ready. Wally Bowman, who oversees DOT operations in Wake and six other counties, said he hopes to finish the work in January.

For John Thaggard of Knightdale, this new Outer Loop leg will cut out a lot of driving on U.S. 64 Business, New Hope Road and Capital Boulevard. "It's going to be a great help to get out to the North Raleigh area," he said.

The northern loop will be a welcome change for many motorists who now pass through the south side of Raleigh via I-40 and the I-440 Beltline -- a route clogged with some of the Triangle's worst rush-hour jams. Among those looking forward to the change are the drivers of state prison buses who ferry inmates on twice-weekly trips between prison units in Guilford and Craven counties.

"The drivers always try to time it so they're not hitting Raleigh during the afternoon rush hour," said Rick Lail, maintenance supervisor at Craven Correctional Institution in Vanceboro, about 115 miles east of Raleigh. "I-540 looks like it might be quicker."

And Lail figures he'll take I-540 himself, when he travels from Vanceboro to visit his parents in Catawba County, about 165 miles west of Raleigh.

Drivers approaching Raleigh from the east on U.S. 64/264 will find signs suggesting I-540 as the best route to Raleigh-Durham International Airport. The new northern arc will run about 26 miles from Knightdale to its western end near Research Triangle Park. That will be a mile or two longer on the odometer, but many travelers will find it easier than taking the southern Beltline.

What about construction on the western end of I-540?

DOT is scheduled next summer to extend I-540 another five miles southwest from I-40 to N.C. 55 in RTP. Engineers recently had hoped to open part of it ahead of schedule -- reaching N.C. 54 by the end of December. But November's rain helped delay things a bit.

"I don't think that's going to happen this year," said Phillip R. Johnson, the DOT engineer in charge. "We would anticipate opening that in early spring now."

On a nearby project to widen N.C. 55 through RTP, Johnson still hopes to open all lanes to traffic by the end of December.

But the N.C. 55 paving is unfinished in several places. DOT will need great weather and good luck to make it happen.