INTERNATIONAL ROUGHNESS INDEX

The Pennsylvania Department of Transportation 
uses a worldwide standard for measuring pavement smoothness called the International Roughness Index, or IRI. The index measures pavement roughness in terms of the number of inches per mile that a laser, mounted in a specialized van, jumps as it is driven across the interstate and expressway system. The lower the IRI number, the smoother the ride. PENNDOT is committed to improving the ride quality of Pennsylvania's interstate highway system. 

The maps to the right indicate the condition at the beginning of 2004 of the interstate highway system, both statewide in Pennsylvania and in south central Pennsylvania - the area for which PENNDOT Engineering District 8 is responsible. In the map depicting south central Pennsylvania, particular attention is given to the Interstate 81 corridor, which has had some of the roughest interstate pavement conditions in the state. The roughest sections of Interstate 81, with an IRI greater than 170, are displayed in the color red. The smoothest pavement is displayed in green. In 1998, PENNDOT began a major initiative to improve Interstate 81 in south central Pennsylvania. This initiative scheduled eight major construction projects to be finished by the end of 2005 addressing 53 miles of Interstate 81 between Route 997 in Franklin County and the northern boundary of Lebanon County. The cost of all eight projects is $189.3 million. Six of these projects have been completed over the past several years.  Interstate 81 through Cumberland County has become one of the smoothest sections of interstate highway in Pennsylvania.  One major reconstruction project started in 2001continues in Dauphin County and is scheduled to be finished this year.  The last of the eight major construction projects on Interstate 81 is now underway in northern Lebanon County.  A ninth project was added to the list this year to repair and resurface four miles of Interstate 81 between Route 997 and Route 30 in Franklin County, as well as build a new interchange (Exit 17) just north of Chambersburg.

 
Major I-81 Projects in South Central Pennsylvania
COUNTY YEAR DISTANCE (miles) COST REMARKS
Cumberland 1998-1999 7.3 $6,546,150 Resurfaced from Stoughstown Road to Stonehouse Road.  Contractor was Valley Quarries of Chambersburg, PA.
Cumberland 1998-1999 5.3 $3,411,527 Resurfaced from Route 11 to Route 114.  Contractor was Handwerk Contractors of Hummelstown, PA.
Cumberland 1999-2000 7.1 $6,897,459 Resurfaced from Route 114 to Susquehanna River.  Contractor was Kinsley Construction of York, PA.
Cumberland 1999-2000 7.2 $8,981,571 Resurfaced from Franklin County Line to Stoughstown Road.  Contractor was Valley Quarries of Chambersburg, PA.
Cumberland 2000-2001 7.2 $8,891,571 Resurfaced from Stonehouse Road to Petersburg Road.  Contractor was Valley Quarries of Chambersburg, PA. 
Dauphin 2001-2004 4.6 $74,499,478 Reconstruct from north of I-83 interchange to Susquehanna River.  Contractor is Trumbull Corp. of Pittsburgh, PA.
Franklin 2001-2003 6.2 $25,435,512 Reconstructed from Route 997 to Cumberland County Line.  Contractor was Angelo Iafrate Construction Co. of Warren, MI.
Franklin 2004-2005 4 $15,663,318 Build new Exit 17 interchange. Resurface between Route 997 and Route 30. Contractor is Hempt Bros. of Camp Hill, PA.
 Lebanon 2003-2005 8.2 $54,638,128 Reconstruct from I-78 to Schuylkill County line. Contractor is Allan A. Myers, LP of Worchester, PA.