In ATAP (the Auckland Transport Alignment Project) one of the ideas that was investigated was the reincarnation of the Eastern Motorway, this time called the Eastern Strategic Corridor. It came about as a result of a push by the NZCID (now just called Infrastructure New Zealand) in their report titled “Transport Solutions for a Growing City“. We covered it back in May last year and it had some useful things about the need for better public transport, smarter road pricing, and alignment of transport & land use etc.
Most interestingly the NZCID commented on the AWHC in its report, remarking that as it stands provides low value for money, and that it needs an Eastern Alignment connecting to an Eastern Corridor to fully leverage the advantage it could provide.
“The proposed Additional Waitemata Harbour Crossing performs the worst economically, delivering a BCR of 0.4.” – Page 31
“A unique advantage of the Eastern Corridor transport solution is the ability to leverage the potential of the largest ever infrastructure project in New Zealand: a $5 billion Waitemata Harbour tunnel. The proposed Additional Waitemata Harbour Crossing is throttled at both its northern and southern termination points, constraining its potential. It cannot connect new businesses and communities and it cannot lift the opportunities for the region, as its predecessor, the Auckland Harbour Bridge has done. Consequently, it cannot deliver economic and social benefits consistent with its high cost and these limitations are highlighted by conventional cost benefit analysis which shows a return of 40 cents for every dollar invested.” – Page 63
In response the ATAP team commissioned a report by AECOM called the Eastern Strategic Corridor Assessment and the report says some very interesting things. They looked at two different options – also shown on the map below:
- a motorway option connecting to an Eastern Alignment AWHC that ends at the intersection of Mill/Murphys Roads, and
- an expressway option connecting an Eastern Alignment AWHC that ends at Allen’s Road.
Whilst the motorway options performed better than the expressway option due to reaching further south adding to the catchment, the report found that the corridor did very little to reduce congestion across the network.
“Congestion across the network exhibits only minor changes as illustrated by Figure 16 and Figure 17 below. Apart from the Motorway option in the AM peak, which shows a decrease of 1.3%; there is less than a one percent decrease in hours spent in severe congestion which is defined as LOS E or worse for all other scenarios.” – Page 11
The real kicker though, comes when they estimated the cost for each option and the AWHC. The expressway option came in at a whopping $10.89b with the Motorway option higher again at $11.26b. The (BCR) Benefit Cost Ratio for the expressway option was just 0.2, and the motorway not much better at 0.4. I am not a fan of making conclusions solely on the BCR due to limitations in the way we model it, however the seriously low BCR is concerning.
What’s worse is that elements in the BCR such as travel time savings are likely overstated
“As can be seen from table 6 above, preliminary BCR’s both options as modeled present poor value for money coming in well below 1.0, meaning that the NPV benefits do not outweigh the investment costs. The Motorway option has substantially higher benefits than the expressway, particularly as would be expected in travel time savings. However it must be noted that the tunnel components for the Motorway option has been modeled as a 100kph posted speed limit. To date, road tunnels in New Zealand have only been posted at 80kph generally as a compromise between safety requirements and cost. As such a modeled posted speed limit of 100kph may not be achievable in practice and the travel time savings, and attraction of the route may be overstated in this test.” – Page 16
They also suggest that further investigation is likely to reduce the BCR on balance rather than increase it
“The motorway would require the acquisition of land to construct 15.5 km of road and 8 intersections/interchanges. Given the above it is unlikely that further more detailed development of the eastern corridor and refinement of costings would improve the BCR. On balance if seems more likely that if would result in a lower value.” – Page 18
Whilst they found the route provided resilience for the transport network, it does very little to address congestion and the high capital costs outweighs any benefit. Still, they advised keeping the existing eastern corridor designation until Smarter Pricing and the western alignment for AWHC is agreed.
“However we also recommend that corridor protection for the eastern alignment should be maintained until such time as the ATAP Government agencies commit to both the additional western alignment of AWHC and the use of the smarter road charging approach being developed within ATAP.” – Page 18
So, the NZCID is saying the western alignment of AWHC provides very low value for money and the AECOM report shows that leveraging any advantage of a new eastern corridor also results in low value for money, as the BCR is 0.2-0.4. The eastern corridor didn’t make it through in to ATAP but some serious questions need be raised regarding the viability of AWHC given even the infrastructure lobby don’t think it’s a good idea.
The Eastern Motorway: killed socially/politically in 2004 and academically in 2016.