Drivers along Route 28 in the months ahead occasionally will be asked to stop and patiently wait -- and they might want to cover their ears -- as crews blast rocks from the hillside as part of a project aimed at stopping rock slides.

The $8.5 million project, announced by the Pennsylvania Department of Transportation yesterday, will start March 3, south of Barge Basin Bridge, and will involve the drilling, blasting and removal of an estimated 77,000 cubic yards of rock and debris.

"During the blasting, we will stop traffic 15 to 30 minutes," said District 11 Executive Dan Cessna. "That will occur during the day. We do not do blasting during the night. We won't do it during the peak hours.

"Basically, after the morning rush, we will stop traffic in both directions, and our goal would be 15 minutes."

Traffic also will be stopped on nearby Freeport Road as a precaution, he said.

It will be the first major rehabilitation of that section of Route 28 since the roadway was built in the early 1970s.

Mr. Cessna said there will be 16 controlled blasts by Kesko Inc. of Butler over a 16-week period. The blasts, which will be done along 300-foot sections through late July, will be announced beforehand, he said, so drivers will have the opportunity to avoid the area.

Once a section of rock is blasted away, he said, the rock face, which will "step" down the hillside, will be smoothed. "Shotcrete," a concrete-type material that fills voids and prevents erosion, will be added. Rock that falls into the catch basin below will not be removed until mid-September, well after all blasting is finished.

Other improvements will be a widening of the catch basin at the foot of the hillside and erection of 1,600 feet of protective rock fall fencing in October.

The project, with finished paving, should be completed by the end of the year, Mr. Cessna said.

"Our engineers are very confident that this is a long-term solution to this very problematic rock fall area," he said.

PennDOT also announced single-lane restrictions for northbound Route 28 from the Barge Basin Bridge, south of the Route 910 Harmar interchange (Exit 11), to the Creighton interchange (Exit 13), beginning March 3.

The work, which includes bridge repairs, concrete reconstruction and repaving, is part of the $35 million improvement project that started with the southbound lanes last year.

The single-lane closings will be during off-peak hours for the first week of work, then, beginning March 10, the closings will be around-the-clock. PennDOT officials hope that closings will be reduced to off-peak hours in June.

Southbound Route 28 lane closures will begin in mid-March, officials said, though the restrictions will be off-peak and there will be no closures during the morning rush hours of 5 to 9 a.m. The southbound work that remains includes paving and some ramp improvements.