The Wellingtonista has posted an email from the AA which urges people to make a submission at the Greater Wellington Regional Council website in favour of Transmission Gully. It seems to me that listening to the AA's views on motorways is a bit like listening to an alcoholic's views on liquor licensing, but one should pay attention to their case. Libertyscott also has a very extensive analysis of Transmission Gully and other options, and his findings are perhaps suprising.
There's one claim that Scott repeats from the Regional Council's analyses which always seemed dubious to me: "rail improvements will shift 500 people a day from car to rail, but only remove 100 vehicles from Ngauranga Gorge at peak times." I've waded through the reports and analyses on the GWRC site to work out what that statistic is based on.
It turns out that they're not talking about capacity: in fact it would only take minor infrastructural upgrades to increase capacity by 3300 passengers during morning peak (see page 5 of the rail options report). They're basing the 500 people a day on their Transport Model (p62) that includes population and demographic forecasts, and some assumptions about improved demand due to slightly faster times, better rolling stock, Waikanae electrification and other relatively minor improvements.
What the model doesn't seem to take into account is any new disincentives to road travel as an option, whether deliberate (tolls, congestion charging, HOV lanes) or caused by external forces (rising petrol prices). It also assumes no changes to land use (such as encouraging Transit Oriented Development and discouraging greenfield sprawl), no other major incentives for rail (extension beyond Wellington Railway Station, aggressive price cuts) and no change in lifestyle and attitudes from our current car dependency.
It seems to me that if we're to find a long-term solution, we're going to have to take a more integrated and open-minded approach that simply relying on engineering solutions and simple-minded traffic modelling. For that reason, I prefer the analysis by Brent Efford (the Environmental Sustainability Representative on the Wellington Regional Land Transport Committee). He has a great summary of the limitations of traffic models that assume indefinite exponential traffic growth, ignore the effects of induced traffic and urban sprawl, and refuse to look at the bigger picture. Efford's solution is neither Transmission Gully nor the full-blown Coastal route, and I'd like to quote it in full:
Is Transmission Gully environmentally sustainable?
Rejecting the Transmission Gully Motorway once and for all should be regarded as a positive first step towards making the slogan "Sustainable Wellington" a reality. The components of an environmentally sustainable strategy for the Western Corridor (and other parts of the Region) are very much mainstream, either currently under study, foreseen in the current Regional Land Transport Strategy, under construction, or well proven by international experience. These components include:
- Completing the basic coastal highway upgrade: the Pukerua Bay Bypass and fourlaning the remaining section to the McKay’s Crossing overbridge. (This does not mean further work in the Mana area outside the current road boundaries, or attempting to achieve a 100 km/h road throughout.)
- Accelerating the rail upgrade: electrification to Waikanae (not just Lindale) and duplication from Pukerua Bay north, plus new rolling stock, extra park+ride, better stations, higher frequency of service, upgraded stations and closer feeder bus integration.
- Travel demand management: consideration of a draft TDM strategy by the RLTC is now underway, with a target of stabilising total VKT at 2001 levels. Achieving this, or at least getting close, would immediately remove any justification for either TGM or a Mana expressway.
- Smart growth in Kapiti: the initiation of an urban growth boundary policy to limit urban sprawl north of Waikanae and into the foothills is an urgent necessity. Further population growth should be limited, with an emphasis on TOD around the railway stations and higher-density infill rather than further greenfield development.
- Transit-orientated development: waste railway land and adjoining low value sites from Glenside north suggest enormous possibilities for TOD along the railway. Prime sites include:
- Takapu Road
- Tawa (note the planning mistake of developing the Tawa Junction shops on ex- railway land but with no connection to the station – and their subsequent commercial failure)
- Porirua (including improved integration with the city centre)
Wind energy: the wind power projects currently planned could make the Region selfsufficient in electricity. The development of this energy source and its use for the railway, and possibly other transport, would be a considerable contribution towards sustainability. Southern extension/light rail: the need to extend the rail service south through the Wellington CBD was first officially recognised in 1959, and has been much studied with positive recommendations since. Recent analysis indicates that eliminating the need to transfer off the train at Wellington Railway Station and having a one seat ride through to Courtenay Place would produce at least a 15% increase in rail patronage. A further increase would be produced if services ran through to the Public Hospital.