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PennDOT Selects Diverging Diamond Option for I-83 Exit 4 Improvements


​Harrisburg, PA – The Pennsylvania Department of Transportation has selected the Diverging Diamond Interchange (DDI) Option for the Interstate 83 Exit 4 Interchange with Route 851 following the public informational meeting that took place at the Shrewsbury Volunteer Fire Company in Shrewsbury, Pennsylvania, on Wednesday, March 30. 

“The diverging diamond interchange was selected over the other option -- a tight diamond interchange -- for several reasons,” said Mike Keiser, PennDOT’s District 8 Executive for south central Pennsylvania. “The diverging diamond interchange can more efficiently handle the heavy left-turn movements experienced at the interchange.  It reduces traveler conflict points for improved safety.  It will function 10-years longer into the future than the tight diamond interchange. And the diverging diamond interchange can be more easily expanded to handle additional capacity should the area grow faster than projections.”
The proposed improvements will include two through lanes in each direction on Route 851, improvements to the ramps accessing Interstate 83, and a new bridge carrying I-83 over Route 851.  The proposed design can be viewed on the project website,  The website contains information on the proposed interchange improvements and a link to a visualization video showing how a diverging diamond interchange functions.
The project is currently in preliminary engineering. Now that a decision has been made on what option to pursue, the plans will be refined before going into final design. After environmental, right-of-way and utility clearances, construction at the earliest is anticipated to start in 2018. The current estimated cost of the new interchange is around $16.9 million.