Highway contracting is big business, and we mean BIG.  The Georgia Department of Transportation has come to a deal with Top End Mobility Group to build and maintain 19 miles of express lanes along I-285 in Atlanta, a project meant to alleviate congestion in coming decades.  Top End will pay $8.9 billion in construction costs in exchange for 50 years of toll revenue from the project, along with a $23.6 billion concession fee.  Those are some eye-popping numbers ahead of a massive project that isn’t expected to be completed until 2042.  The staggering scale and complexity of the highway plan has GDOT and the winning bidders at Top End RISING…