GDOT I95/SR21 Diverging Diamond Interchange

In April 2015, R.B. Baker was awarded the Design-Build project to construct a Diverging Diamond Interchange at the intersection of State Route 21 and Interstate 95 in Port Wentworth, Georgia.  This corridor serves as one of only two commuter routes connecting Effingham County and Chatham County (Savannah).  This Diverging Diamond Interchange allows motorist to move to the opposite side of the roadway through an interchange controlled by traffic signals and then move back to the original side of the roadway once through the interchange.  This concept allows all turns on and off the Interstate Ramps without having to cross a lane of traffic and will allow for increased volumes of traffic due to decreases in conflict points and the signal phasing thus increasing the efficiency of the intersection.  The project consists of approximately 1.0 miles of variable depth milling up to 5 inches in depth and paving 5 inches hot mix asphalt.  Both SR 21 and the I-95 ramps are being widened to facilitate additional lanes.  New signals are being installed for the new traffic patterns.  Other items include median grading, drainage relocations, curb and gutter, handicap crossings, the addition of new signs and significant striping changes.  Traffic was shifted into the new alignment for the diverging diamond mid-December 2016 and the project’s final completion date was early spring of 2017.