Friday, 10 May 2013

Stephenson's Eastern Distributor

I had already made a submission to the Stephenson Inquiry. The Main Roads Department was using tubes fixed to roads to count vehicle movements. The boxes that recorded the pneumatic blips were chained to posts and were not linked to traffic lights. They recorded how many vehicles passed along Flinders Street say, but could not distinguish whether they came from Oxford Street or Bourke Street.  System designers were free to make any assumptions they liked about vehicle flows, and did. However someone in Main Roads had recognized the inadequacy of the data and they had employed students to count vehicles at several complex intersections, including Taylor Square, over a period, on an annual basis. The Surveys had been discontinued for a few years but were archived in the Engineering Library. They confirmed my off-the-shoulder observation that the traffic from Oxford Street to Flinders Street could not be funneled into one lane.

Blip counting does not distinguish between vehicles, a bus carrying sixty people is just two blips like a car carrying one person. However the students had recorded the types of vehicles - cars, buses or trucks. This data confirmed that the Taylor Square intersection was doing a good job in separating south-bound vehicles heading for Port Botany along Flinders and South Dowling Streets, from cars heading for garages in South Sydney. I did an informal count that confirmed that the volumes of traffic had increased since the last survey but the mix was much the same.

My submission was for a south-bound underpass under William Street between Palmer Street Wooloomolloo and Bourke Street and for a north-bound tunnel from the west side of Flinders Street to William Street and under William Street to Palmer Street, which would take traffic out of Crown Street. I pointed out that this was downhill and could have a steeper gradient so all the buildings between Bourke and Palmer Streets, Darlinghurst could be preserved.

Traffic in Crown Street in 1970's
The Minister released Stephenson's report on the Thursday before Easter. I bought the Sunday papers at Midnight on Saturday from the news stand outside the Oxford Hotel, still no reports. I had to wait until after Easter to view the Scheme.

The plan was in three stages: an underpass under William Street was stage one. Stage two was to extend this in a tunnel to Moore Park. Unfortunately a north-bound tunnel from Flinders Street to Palmer Street was Stage Three.

Stage one was built, but the volume of traffic that the Cahill Expressway could deliver would never justify the expense of twin tunnels and the other stages would never be built.

That all changed when a consortium of banks proposed to build a tunnel under Sydney Harbour using technology developed in Hong Kong.

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