It's massively expensive. No debating that. But cutting corners is what got us this tangled mess of infrastructure through Hartford. I'd like to see someone have the guts to do it right now so that we are set for 100 years than just do ok for 50.
Long term transportation planning as been missing from urban development across the US in most cases for decades.
By where I live, the Tappan Zee Bridge is a classic example. It was built in the 1950's at the widest point on the Hudson River not because that is where the engineers said it could be built; but, because the NYNJ Port Authority has exclusive rights over Hudson River crossing within 25 miles or so of Battery Park and the Port Authority and the NY Thruway Authority could not get along. The bridge was also done on the cheap due to limited funding ($81 million) and a steel shortage caused by the Korean War. The bridge, which opened in 1955 was was expected to last 50 years (the Brooklyn Bridge is now +130 years old).
Jump to 2007, 52 years into the bridge's 50 year expected life span, 138,000 vehicles per day were traveling across this bridge that was supposed to carry 80,000 per day maximum. After the I-35W bridge collapse in Minneapolis, politicians finally decided it should be replaced. After years of arguing, the replacement bridge began construction in 2013 (if you go over it now, the world's strongest floating crane is on-site now and it is impressive, can lift entire bridge sections, it was build for the new SF Bay Bridge and sailed over last year) and the new bridge will partially open in late 2016 and fully open in 2018. For $4 billion, we will get a bridge that should last 100 years with 8 lanes (4 lanes of traffic each way) instead of 7 (3 lanes each way, 1 flex lane) and a pedestrian sidewalk. No dedicated bus lanes, no commuter rail linking Rockland County with the MTA Hudson line and Grand Central. So the new bridge will not solve today's current traffic issues never mind future growth. While adding pair of rails to the bridge would have added $500 million to it, at least that would have shown long-term thinking.