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sexta-feira, abril 04, 2008

Critical mass for mass transit

According to an article in the Economist (29-March-2008), Los Angeles is discovering the importance of "transport-oriented development" and is looking for "elegant density" along express bus routes and subway stops.

Elegant density may be an Hollywood concept difficult to translate into economics, but the synergies between urban transport and urban land use planning are easier to understand. Most urban "mass transit" schemes are viable for heavy traffic corridors with relatively high residential population density.

The same is true for other infrastructure networks, like water or electricity. A low density network has a higher cost per user than a high density network. That's why low density rural or far suburban networks with few users often require taxpayer subsidies.
In general, it is important to minimize the dimension of the infrastructure, and the investment cost, while serving the maximum number of users. With lower investment and more users and user fees, the more viable and self-sustaining the public service project.
There is in fact a minimum "critical mass" needed to justify most "mass transit" and transport infrastructure.

2 comentários:

  1. Segundo um artigo no Economist (29-Março-2008), Los Angeles está agora a descobrir a importância dos transportes colectivos no desenvolvimento urbano, promovendo a densidade residencial ao longo dos corredores de autocarros e metropolitanos.

    As sinergias entre os transportes urbanos e o desenvolvimento são fáceis de compreender.
    Os transportes colectivos necessitam densidade populacional considerável.

    O mesmo acontece com outras redes de infra-estrutura como a água ou a electricidade. Redes de baixa densidade têm um custo/utilizador mais elevado do que uma rede de mais alta densidade. Por isso as redes rurais com poucos utilizadores têm menos receita e dependem mais de subsídios dos contribuintes.

    Em geral, é importante minimizar a dimensão da infra-estrutura e o custo do investimento servindo o máximo número de utilizadores, para tornar o projecto mais viável.

    Assim, as "massas" são de facto a parte importante dos "transportes em massa".

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  2. There seems to exist a generalized misconception that the traffic forecasts are “confidential”, especially before, during and after the PPP tender processes, where the traffic risk may be taken by the bidder.
    In my view, and speaking both for the user and for the taxpayer, transport planning and financing is all about “traffic, traffic, traffic”, regardless of who is taking traffic risk.
    So keeping traffic forecasts confidential throughout the process is like planning a meal (be it a simple supper or a fancy banquet) without knowing how many people are coming to dinner!
    If necessary, the bidder´s traffic forecasts should be confidential only from the moment of the initial bid until the contract is adjudicated and signed, and only if they are taking traffic and revenue risk. This is not the case where the state will make availability payments.
    The Government's traffic forecast (Concedente) is never confidential and should be scrutinized by the parliament and the representatives of the taxpayers in the consensus-building process.
    Therefore, getting access to traffic forecasts is essential but will probably require some formalities, since it cannot be left up to chance.

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