Interstate highway construction that has clogged traffic in Pittsburgh, west of the city and east of the city will begin in the north by the end of the month.

Construction on I-279, the Parkway North, is scheduled to start when Memorial Day weekend ends, on May 27. At that time, part of the high occupancy vehicle lanes will be closed at the McKnight Road interchange to get the project under way.

The work this year will cover an eight-mile area from East Ohio Street on Pittsburgh's North Side to the Camp Horne Road interchange near the Ohio Township-Ross line.

The Pennsylvania Department of Transportation has received an $11.3 million low bid for the work. The remaining five miles from Camp Horne Road north to the I-79 junction in Franklin Park will be rehabbed under another contract during the 2009 construction season.

In a news release, PennDOT emphasized in bold type that "Motorists should expect significant impacts to traffic," including lane and ramp closures, shifting traffic patterns and other restrictions.

An average of 110,000 vehicles a day travel the busiest stretch of I-279 set for construction this summer. In addition, nearly 4,000 vehicles a day use the 4.1-mile reversible HOV lanes that require a minimum of two occupants per vehicle during rush hours.

PennDOT officials are to hold a news conference within two weeks to provide detailed information about work that will be done in phases:

HOV lanes, followed by inbound road and bridge repairs, followed by outbound road and bridge repairs.

"This project represents the first rehabilitation of the Parkway North since it was constructed in the late 1980s," PennDOT District 11 Executive Dan Cessna said.

"This timely preventive maintenance project will provide a significant life extension to this section of roadway and many bridges within the limits of work.

"We understand this project will have an impact on the traveling public, but it is essential that we conduct these preservation activities now, before drastic work becomes necessary."

The work comes at a time when PennDOT already is:

• Building two "missing ramps" at the Parkway West/I-79 interchange near Rosslyn Farms, the busiest interchange on the 180-mile-long interstate from West Virginia to Erie.

• Rehabilitating more than six miles of I-79 between the Ohio River and the I-279 junction in Franklin Park.

• Rehabilitating I-579, called the Crosstown Expressway below Mellon Arena, one of the nation's shortest stretches of interstate.

• Repairing three miles of the Parkway East/I-376 between the Edgewood-Swissvale interchange and Business Route 22 in Churchill.