So the boston big dig is 3.5miles so about 3 times the length. Even in the beginning it was estimated to be 2.8billion (in 1982 dollars). So here we are in 2017 with a project 1/3 the size estimated to cost 1/10 the price. And the big dig went on to cost 14 billion. Its why I laugh when I hear local leaders saying they will put I-35 in a tunnel for 2 bil. Or why I laugh and continue to laugh at the clusterF they are doing on MOPAC. Its going to be 2 years late at least and some crazy amount over budget. Or the flood tunnel they put in to beautify downtown that went over budget by 3X and is still not complete.