I have, what I believe looks quite simple but is perhaps quite complex. It's related to transport modelling. I'm creating a fairly standard Alt-Spec design for mode choice (Bus, Tram, Car etc.) and price along with some other variable such as wait times for bus and tram etc.
However I have a conundrum. In my Car alternative I have a daily parking fee ($10, $15, $20 etc) but I would also like to include a toll road fee as well ($5.50, $6.50 etc.)
How would I estimate single price based demand curve for car (which technically there will be two of, one for parking and one for toll) or a simple WTP (price change over utility change) for attributes such as travel time or traffic congestion or any other variable that might be applicable to the car alternative?
Could a solution be to code toll as a continuous variable generating a single parameter for all the levels and then add that part-worth to each level of the price utility.
Any help would be most appreciated.