The construction of Boston’s Big Dig highway tunnels has gone down in history as one of the most infamously delayed and over-budgeted infrastructure projects in the sorry annals of U.S. growth and progress. But Ian Coss sees the project radically different. In hindsight, he argues, the Big Dig was a steal: the good kind. Far from being a gargantuan boondoggle, the project resuscitated downtown Boston and ushered in urban economic benefits and spillovers that dwarf the costs of the project, however one might calculate them.

Ian interviewed more than 100 people connected with the Big Dig and spent months editing a nine-episode podcast series titled “The Big Dig” for GBH News, Boston’s National Public Radio affiliate. Through the series, he covers everything from the environmental consciousness of the 1960s and colorful yet idealistic local political figures to the Department of Transportation’s inflation estimate policy and ultimately the decades it took to bring the dream of burying Boston’s unsightly Central Artery freeway.

On today’s “Securities” podcast with host Danny Crichton, Danny and Ian debate the merits of the Big Dig megaproject, the complicated construction policies that made the project seem like a loser in front of the public, and just how hard it is to measure the true impact of a project that forever transformed one of America’s founding cities.