Transport Appraisal and Dependent Development. What Are We Measuring – and Who Benefits?
Hermann Maier, Jacobs
Based on recent project examples in the UK and a review of international practice, this paper explores where there are overlaps, gaps and double counting in current appraisal practice for transport projects that facilitate land use development.
Variable trip matrix techniques have long been used in transport appraisal but they can only deal with the changes in trip patterns directly related to a transport intervention. Appraisal in a context where the land use changes between appraisal scenarios has long been a problem. Although mathematically, variable trip matrix techniques could be applied, the results become un-interpretable.
In response to this conundrum, the UK Department for Transport has issued guidance on “Appraisal in the context of dependent development”. The main principle is that the value of the transport intervention should be appraised in the absence of the additional development while the value of the development is assessed separately in terms of a land value uplift. This typically leads to relatively low transport-economic benefits and high land value benefits which are based on benefits calculations that are analytically less rigorous than the conventional transport-economic appraisal.
Furthermore, it is unclear who the beneficiaries are and to what extent these land value uplift represent an overall benefits to the economy.
Meanwhile, Transport for London has come to the question from a slightly different angle. In the “Opportunity Area” studies, the question is not how much development is dependent on the transport intervention but what transport interventions are required in order to facilitate certain development levels. The assessment here typically involves the creation of a range of land use scenarios which provide the context for the appraisal of different packages of transport interventions.
Related to these issues is the appraisal of “Wider Impacts”, of which “agglomeration” tends to be the dominant one. While not directly related to land use development, the associated concentration of activities implies land use changes and intensification of development.
While the theory and practice for the calculation of pure transport economic benefits is well developed, techniques for assessing these additional effects are still evolving.
The difficulty in appraising these effects is mirrored by a difficulty in capturing some of these benefits. Attempts to capture the value of land use changes directly associated with transport schemes are not always effective. In the UK, for a long time, there has not been an effective taxation mechanism to capture this. The Crossrail scheme in London has pioneered the use of the Business Rate Supplement (BRS) and Community Infrastructure Levy (CIL) to make a contribution to the funding of the scheme. However these are rather blunt instruments.
Based on recent project examples in the UK and a review of international practice, this paper explores the questions –
- Where are the overlaps, gaps and double counting in current appraisal practice?
- Who do development benefits accrue to?
- How are developer contributions treated in appraisal?
- What mechanisms exist to capture these benefits and how do they relate to the appraisal techniques used?
Association for European Transport