A paper by the prolific, comprehensive and well cited Todd Litman summarises what the problem is with transport economics, or rather, what the many problems are. The bottom line is that conventional cost benefit analysis:
“tends to favor economic objectives (because they involve market resources) over social and environmental objectives; industries (which have more financial transactions) over communities (which involve more non-market transactions); wealthier people (because they purchase more market goods) over poorer people; and the current generation over future generations” (Litman, 2009, 1-13).Strange thing is, if you raise these many concerns about transport economics with mainstream transport planners you get a sort of blank stare; a muffling about economic growth, or outright aggression.
When you drill down, though, as Litman does in his paper then you see that traditional transport economics is based on some pretty dodgy premises. At the very least traditional transport economic analyses demand interrogation.