NCE tracks the rising cost of the Boston Artery project
The first Big Dig cost estimate was said to be a 'back of the envelope' calculation of £1.6bn in 1982.
The then Governor of Massachusetts, Michael Dukakis, had to battle against the hostile Republican Administration to win federal funds for the project. Ronald Reagan's Administration was said to be loth to pour so much Federal cash into a state that was strongly Democrat. But the fact that the project would finally connect Logan Airport with the interstate highway I-93 and strong support from Democrat speaker of Congress Tip O'Neil helped Massachusetts win the day.
Since approval was gained in the mid 80s, on the proviso of using programme managers Bechtel and Parsons Brinckerhof, about 100 scope changes have been made to the project. The first 'legitimate' estimate based on the current scope of the project was £3.6bn, made in the early 90s, which then rose to £4bn.
The next major rise resulted from the now legendary redesign of the Charles River crossing. Then Massachusetts Secretary of Transportation Richard Taylor responded to complaints about the aesthetic qualities of the original bridge design by setting up a committee to consider options for a complete redesign. A source close to the project claimed that the original £375M proposal, known as Scheme Z, needed modification but not a complete redesign.
'The forming of the bridge design review committee was complete insanity. It had no financial restraint, it took the 40/50 appointees a year to consider three different options before deciding on the cable stayed bridge. The new bridge cost nearly £600M as well as another £600M in lost time', claims NCE's source.
The redesign of Scheme Z caused the Big Dig's cost to soar to £4.8bn. It was later announced that with inflation over the years, the cost would be £6.5bn which was upped to £6.8bn in 1997. The latest projection of £7.6bn was announced on 1 February, but a recent review of costs by US programme manager O'Brien Kreitzberg states that an extra £200M could be needed on top of that.
Others argue that the projected cost can now be reduced. A Big Dig spokesman said: 'We've done 70% of the excavation, the slurry wall construction is 90% complete, the tunnel jacking 70% complete, the first immersed tube tunnels are set and the cable stayed bridge 40% complete. The worst technical challenges to really hit the budget are over.'
The £900M overrun on the 1997 £6.8bn budget includes:
£200M to keep to schedule.
£200M in change orders to existing contracts.
£40M in extra design.
£45M on right of way purchases.
£60M spent on interfaces with businesses and utilities.
£160M to Bechtel/Parsons Brinkerhof.
£195M ...other costs