I hear you Roverman, however I challenge anybody to realistically drive the competing journey within the same time boundaries, within legal speed limits and arrange suitable parking within reasonable distance of the finishing station for the same price.
Aren't you assuming everyone lives next door to the originating station and their destination lies next to the target station, and the journey lies on the same radial route? ? I commute Southampton to SLough (am 2 hrs, pm 2.5hrs). Marginal cost = ticket (£28.80) + car park (£12) + fully depreciated mileage to/from stn (£12) = £53 for 150 miles = 35ppm with a mile walk each way on top rain or shine. Reliability factor 90%. Comfort factor 50%
THe car takes 1.5 hrs. Marginal cost (opex) = 17ppm, reliability = 95% comfort = 95%.
So you tell me where is the incentive to do other road users a favour and take the train?
I can monetise the capex on the car as (mileage 10k pa, depreciation £3kpa, insurance £500, tax £200, servicing £500 and fuel economy 8 l/mile @ £1.35 /litre. Put that lot in and the car's gross cost rises to 50-60ppm but Goatboy is right - we own cars anyway so you cannot just spread your capex in that way - it is bad economics.
SOmeone at the start of the thread asked what is a realistic price for a train journey. here's a stab.
If I can sit in comfort and do productive work for half the journey that is 2 hours in a working day, and that is my (only) value proposition for rail. If the train is crowded, or uncomfortable like the hideous 220 voyager then I have to pay a further first class uplift fare to guarantee working conditions which blows the rail business case apart once again.
An attractive peak fare for my 150 mile commute journey should be around £20, or say 15ppm. The car park should be £5 per day, not the rip off it is , otherwise it is not economic, as the figures show.
Finally I want the railway to compete with roads as a social railway, not with airlines for Gods sake. Where the hell are we going with transport policy?