As part of the Survey Report and after analysing the financial and functional attributes of each of the four alternatives, a cost-benefit Analysis (CBA) and a Multi-criteria (MCA) Analysis were carried out.
The financial profitability of the options was examined with the CBA, which involves adding the project's costs and benefits algebraically for the agents that represent the whole of the society affected by the project. According to the results of this analysis, alternative 1 is the preferred option, given that:
- Its social internal rate of return (SIRR) is the highest.
- Its period of return on the investment (payback) is the lowest (12 years, compared to 30 for the second alternative).
- Its profit-costs ratio is the highest.
Alternative 1 (Overground tramway along Avda Diagonal with reserved platform) was proven to be the best from the point of view of all users (public transport and private vehicles).
As for the multi-criteria Analysis, this takes account of the level of compliance with 6 goals, under the weighted and straight-line methods, as well as the values of 17 indicators resulting from these 6 goals:
- Maximising the demand served.
- Improving the public transport system (connectivity, facility, efficiency of use, etc.)
- Minimising the impact on the environment and externalities (building and usage phase).
- Maximising profitability and financial efficiency.
- Maximising the project's capacity in the existing urban network and promoting urban insertion.
- Maximising the macro-economic impact on the Catalan economy.
The results of the MCA show that alternative 1 proves to be the most advisable as it outweighs the other alternatives in goals 3 and 4 (which weighted and summed represent 50%) and comes second best in goals 1, 2 and 5. Alternative 2 (tramway semi-underground along Avda Diagonal) is better than alternative 1 with a certain margin only in goal 6: Maximising the macro-economic impact on the Catalan economy, and presents good results in the goals; so it comes second in order of points.
To conclude, alternative 1, overground tramway along Diagonal with a reserved platform, and alternative 2, a semi-underground tramway along Diagonal, are the two best options according to the multi-criteria Analysis. Alternative 1 prevails over alternative 2 in 4 of the 6 goals and in 11 of the 17 indicators, whereas alternative 2 performed better in 2 goals and 2 indicators. Both achieve the same level of compliance with 4 indicators: Intermodality, acts as a barrier for vehicles (reducing accessibility) and reducing parking places.
The best option, therefore, according to the cost-benefit Analysis and the multi-criteria Analysis and other aspects considered in the Survey Report is the first one: The overground tram section along Avda. Diagonal with reserved platform.