Changes to surface roads were developed as the tunnel's design evolved. A total of 73 road changes were eventually approved in response to the EIS and Supplementary EIS. Twenty-eight changes resulted from the EIS process for the initially approved design. A further 45 changes were introduced on accepting CCM's 'Long 80'. Of these 45 changes, nine were new MAEs. They were all proposed by the RTA.
The RTA proposed the road changes based on assumptions of high traffic volumes using the tunnel. The DoP accepted the proposals because of concerns about 'induced traffic' effects if so many cars used the tunnel. Induced traffic means if the surface streets became relatively empty, they would attract new drivers to use them to get into the City.
The surface roads would only become relatively empty once large numbers of vehicles start using the tunnel. If the assumptions are wrong, fewer vehicles will be using the tunnel and more than anticipated will still be using the surface streets.
In view of the high traffic volume estimates for the tunnel, the RTA and the DoP decided that road restrictions (beyond those originally planned for the central corridor of William, Park and Druitt Streets) would be necessary from the outset. This was because the agencies believed that there would be a significant immediate reduction in surface traffic, which would immediately attract more cars, and hence the benefits of reduced congestion would be lost.
If there was greater emphasis placed on expanding, improving and marketing public transport from the opening of the CCT, the threat of attracting new road traffic would be less. Enhancement of public transport may involve some further road changes.
The RTA developed the road changes in response to the EIS and the Supplementary EIS. It aimed to integrate the tunnel with the road network and benefit the environment and transport within Central Sydney. CCM requested one change which was denied, as discussed earlier. Exhibit 4.3 summarises the road changes introduced at the EIS and the Supplementary EIS stages.
Exhibit 4.3: Road changes introduced at the EIS and SEIS stages | |||
Stage at which road changes were initiated | Category of road changes | ||
| A (MAE) | Other (B, C, D) | Total |
EIS process - initial approved design | 13 | 15 | 28 |
SEIS process - 'Long 80' modified approved project | 9 | 36 | 45 |
Total | 22 | 51 | 73 |
Source: RTA advice to the Audit Office, December 2005 | |||
The 45 changes introduced as a result of the Supplementary EIS and the DoP revised Conditions of Approval were as follows:
■ 3 related to changed tunnel portals (i.e. tunnel openings to surface roads)
■ 15 related to the central Druitt, Park, William Street corridor (i.e. the central corridor)
■ 27 affected surrounding surface streets particularly in Kings Cross and Woolloomooloo (i.e. approaches to the tunnel).
The DoP required a number of changes to traffic flow arrangements. These were influenced by the large traffic volume projections by CCM and the RTA for the 'Long 80' design.