Policy results and recommendations

The results from the optimisation process are summarised in Table 2, which gives an overview of the relative benefit (over the nine case study cities) of each measure with respect to the two objective functions used.

From the results in Table 2 and from other aspects of the research, the following recommendations can be made for policy makers:

• strategies should be based on combinations of measures, and should draw fully on the synergy between success measures;
• economically efficient measures can be expected to include low cost improvements to road capacity, improvements in public transport (increased service levels or reductions in fares), and increases in the cost of car use;
• public transport infrastructure investment is not likely, in the majority of cases, to be a key element in economically efficient strategies; · reductions in capacity to discourage car use are not likely to be economically efficient;
• the scale of changes in service levels and fares will be influenced by the current level of subsidy; in some cases a reduction in service levels or an increase in fares may be justified on economic grounds;
• the scale of increase in costs of car use will depend in part on current levels of congestion; the study suggests that road pricing and parking charge increases are broadly interchangeable, but this needs assessing in more detail;
• in most cases economically efficient strategies can be designed which are financially feasible, provided that revenues can be used to finance other strategy elements;
• the pursuit of sustainability is likely to justify investment in public transport infrastructure, further improvements to public transport services and/or fares, and further increases in the cost of car use;
• availability of finance will be a major barrier to implementation of many sustainability-optimal strategies, and further work is needed to investigate the extent to which financial costs can be reduced by strategies which are slightly sub-optimal;
• legislation will be needed to enable implementation of road pricing and to control parking charges; in the UK and Italy there is also a case for changing legislation to permit economically more efficient public transport strategies;
• public acceptability will be a significant barrier with those measures which reduce service levels or increase costs; this implies the need for effective public relations campaigns, and carefully designed implementation programmes;
• detailed measures to improve the environment and provide better facilities for cyclists, pedestrians and disabled people should be designed within the context of a preferred strategy.

Methodological conclusions and recommendations

• the optimisation procedure has been shown to be successful, and has attracted widespread interest; however, it is important that careful thought is given to the policy implications of each stage of the process;
• the frequent use of upper and lower bound values in the optima is a cause of some concern;
• strategic models are in many ways more appropriate than tactical models in the development of optimal strategies;
• such models should include walking and cycling, both peak and off peak conditions, and the effects of public transport loadings on user costs;

Collaboration sought for Exploitation (Academic exploitation)

• Research organisations overseas (i.e. outside EU) who have an interest in strategic modelling and optimisation. In particular, research organisations in Asia and Latin America would be particularly appropriate.
• Research organisations involved in combining land use modelling with strategic transport modelling, who have an interest in optimisation.
• Research organisations involved with developing national/international models, who have an interest in optimisation.

Consultancy

• Cities who already have existing strategic transport models, and would like to make extra use of these models by using the OPTIMA optimisation method.
• Cities/consultancies who are already building strategic transport models.
• Cities/consultancies who are planning to build strategic transport models in the future.