JACKSON TWP - State officials believe motorists merging too early through a construction zone on Interstate 79 between Zelienople and Portersville has been the cause of major traffic headaches in the past several weeks.

Traffic has backed up for miles in the construction work zone several times in the past few weeks, causing delays along I-79. A major tie up happened on July 9, which caused vehicles to back up through downtown Zelienople.

Jim Struzzi, spokesman for the Pennsylvania

Department of Transportation

, said the department officials believe motorists are merging miles before the work zone causing traffic to back up earlier than the designed merge point.

"Motorists need to use both lanes until the merge point," he said.

Struzzi said tractor-trailer trucks have been blocking both lanes and not allowing motorists to pass.

"They probably think they're helping us, but they are really causing the traffic to back up further," he said.

The traffic tie ups have occurred despite PennDOT prohibiting the contractor, Lindy Paving, from restricting lanes northbound from 3 to 7 p.m. and southbound from 6 to 10 a.m. to accommodate rush hour traffic coming from and going to Pittsburgh.

Zelienople police chief Jim Miller said the traffic problems on July 9 that caused traffic to back up through the borough up Route 19 into Jackson Township was caused by miscommunication between the contractor and the state police over traffic control. He said the paving work has not caused a traffic back up in the borough since then.

PennDOT is in the middle of a $3.7 million resurfacing project on I-79. Work began in April and is expected to continue into the fall.

The project is about half done. The contractor has completed the northbound passing lanes and this week will begin work on the northbound travel lanes. Working hours are scheduled from 7 p.m. to 11 a.m. through today.