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Transport Appraisal – what it is and why we do it Tom Rye, Professor of Transport Policy and Mobility Management Transport Research Institute Edinburgh Napier University
Session objectives n To consider why we need to appraise in transport n To explain in brief some methodologies and look at some examples n To consider the political benefits of appraisal n To understand scenario planning n To develop our own appraisal framework
Why appraise? n When you buy a new house – do you just buy the first one you see? n Factors you might take into account: • Size • Location • …. . n Maximise benefits of the house within a given budget n Benefits/attributes of house - not same for all people • Near public transport • Near a school • Has swimming pool
Transport – similar n More projects exist than money to fund them n Need some way to choose between them n Maximise benefits we get for money spent n Achieve objectives n Give taxpayer value for money n (May) make decision-making transparent n Can make decisions easier to defend n May make projects more “thought-through” – so more effective/higher quality n BUT – we cannot see the project before we buy it – so we have to PREDICT its impacts
Choosing which tram line to build
Some different methods of appraisal
Cost Benefit Analysis 1 n You are considering converting a freightonly railway line in suburban Ljubljana to S-Bahn operation with new stations and a train every 15 minutes. n What would be the benefits and costs? • Benefits • Costs
Cost benefit analysis 2 n When you have predicted all benefits and costs for the scheme for years into the future… (requires modelling…) n Change them into a common unit (€€€€) n Add them up n Subtract costs from benefits n Result, or ratio – shows value of scheme n Example – German Standardised Assessment for Infrastructure Investment n Any problems with this method?
Objectives-based appraisal n Set a number of agreed objectives n Assess scheme’s performance in relation to these n Do not have to all be in money form n Example of this system – UK Web. TAG www. webtag. org. uk n See also sheets handed out n Any problems with this method that you can see?
Multi-criteria analysis n As objectives-based appraisal, but then: • Score performance of scheme against objectives • Weight objectives • Calculate overall score for each scheme • Fund schemes with best score – or those delivering most score per € spent n Examples: • Many local authorities, UK (local safety schemes) • Swiss Cantons e. g. Canton Zuerich
Key requirements for appraisal n Agreement on benefits and costs, or objectives, to include in appraisal n Monetary values of costs and benefits (for CBA) n Weightings for objectives (for MCA) n For larger, longer term schemes – a model n Indicators e. g. total accidents; or a rate? n But… n Size of appraisal should relate to size of scheme
How to use appraisal in decision-making n Decisions about new schemes – always political n Appraisal can aid political decisions, though – can makes it easier for politicians to say: • We have taken everyone‘s needs into account • We have looked at many different options, and this one is the best • This new railway is excellent value for money • Our new system of traffic calming will save XXX lives a year • The new busway/road/bikeway/MM scheme will bring € 3 of benefits to Ljubljana for every € 1 we have spent on it • This scheme achieves our objectives