Motorists will begin using part of the new Main Street Viaduct late this year. That's the good news.

The bad news is the current bridge will be closed this summer, and a detour will be in effect for nearly four months.

That means Route 8 traffic south of Butler will use the Picklegate Crossing in Lyndora.

"It's going well," said George McAuley, the state Department of Transportation's assistant district executive for construction in District 10, which includes Butler County.

"The warm weather helped," he said of the bridge project.

McAuley said the bridge detour will begin in mid-July.

The bridge is being built in two sections. When the southbound section is finished and connected to Main Street, the detour will no longer be needed.

Traffic in both directions will then be diverted onto the southbound section while the northbound section is completed.

McAuley said the contract requires the detour to be no longer than 15 weeks.

While the detour is in place, traffic will be directed to use the Picklegate bridge, Hansen Avenue and Route 356.

Construction of the $23.1 million bridge began in early June. The contract calls for work to be done by November 2006, McAuley said.

After the bridge is finished, PennDOT plans to begin work on the new Wayne Street bridge.

While some of the bigger PennDOT projects in the area have now been finished, such as the Cranberry Connector linking the Pennsylvania Turnpike and Interstate 79, and the Route 422 interchange in Summit Township, PennDOT officials have several other projects planned for the 2005 construction season.

This spring, work will start on the Route 356 and Sarver Road intersection project. That involves realignment of the intersection, installation of traffic signals and left-turn lanes on Route 356. The project is scheduled to be finished by this fall.

Other major road improvements in the county include resurfacing Route 138 between Routes 38 and 308; Route 28 in Buffalo Township; Annisville Road in Parker Township; Campground Road in Mercer Township; portions of Route 8 in Butler and Penn townships; Reibold and Brownsdale roads in Forward Township; and Glen Eden and Franklin roads in Cranberry Township.

The southern third of Interstate 79 in the county also will be repaved this year. The middle section was done last year. The northern third is scheduled for next year.

Other bridges being replaced include the McDeavitt Bridge on Fenelton Road in Clearfield Township and the Monroe Road Bridge in Buffalo Township, which was destroyed in the flooding on Sept. 17. Also planned for replacement is the Carbon Center Bridge in Summit Township.

In Allegheny County, motorists will encounter construction on Interstate 79 in Marshal Township and Route 8 in Shaler Township and Etna.

Interstate 79 will be reconstructed between Route 910 and the Cranberry Connector, PennDOT District 10 spokeswoman Cathy Tress said.

On Route 8, workers will straighten a bend, widen the lanes and lengthen the ramps from Route 28, she said.