We need a managed system of conversion from the old oil economy to the new solar economy. Any other system (based on price signals alone) will almost inevitably be wasteful, unfair, anarchic and potentially lethal.

The system would be simple and unbureaucratic, with everyone 17 and over being issued with a fixed amount of petrol/diesel 'vouchers' allowing a certain amount of petrol. These vouchers would also be issued to non-drivers. The amount allowed would be based on the previous years total petrol consumption divided by the number of people over 17 in the country. Each year,over a 20 year period, 5% less petrol would be available from the starting amount. This would create an oil-less economy within 20 years, something that is likely to happen in any case.

There would need to be a centralised trading system set up so that heavy users could buy vouchers from those that don't need them. This would provide a nice extra income for non-drivers!

Taking the medium-term view the knowledge that each year would see a 5% reduction in the availability of petrol everyone would seek ways of reducing their consumption and changing their lifestyle to make the change easier.

Bear in mind also that pricing signals will also have a dampening effect on consumption.

Similar rules would need to apply to both public transport and freight transport, switching all public transport and freight to a vastly expanded heavy and light railway network over 20 years.

With everyone involved in one way or another in the transition to a solar transport economy life will be made much easier for those wishing to bring this on - objections to new railways and tramways for example would vanish overnight! Sales of alternative fuel cars (which will always be a tiny percentage of what we have now) plus more efficient oil-based cars (for a few years) would also blossom, as would growth in walking, cycling and horseriding.