Interstate 83 (I-83) Exit 4 is an existing diamond configuration interchange with signals located at the ramp intersections with PA 851. Due to the growth of the Shrewsbury area, congestion is experienced at the interchange during peak periods, and traffic exiting I-83 northbound and southbound backs up onto I-83. Two options were developed for the reconstruction of the interchange, the tight diamond interchange and the diverging diamond interchange.  Following option development and public involvement, including a public meeting held on March 30, 2016, the diverging diamond interchange was selected to advance into final design.

The Diverging Diamond Interchange (DDI) configuration will have two eastbound and two westbound lanes on PA 851 and utilize signalized ramp intersections to cross traffic over to the left side of the roadway with a return to the right side within the interchange limits. It will improve traffic flow, particularly for left turns, to and from I-83. The design will include the replacement of the bridges that carry I-83 over PA 851 with two-span structures that will accommodate the additional lanes on PA 851 as well as possible future widening of I-83. The Deer Creek culvert under the interchange will be replaced. Also included is the lengthening of the I-83 northbound and southbound on and off interchange ramps. Two lanes of traffic in each direction will be maintained on I-83 throughout the majority of construction.

Please refer to the resource documents on the right for more information.