Theoretical Justifications Current transportation systems are often inefficient because they violate basic Market Principles . Consumers often have few viable transportation options. Prices do not reflect full marginal costs. Planning practices are often biased. TDM can help correct these distortions.
Many people are skeptical.
The answer is that current market distortions encourage inefficient travel behavior. Although consumers may perceive direct benefits from driving, these are offset by additional costs borne elsewhere in the economy. In a more efficient transportation market, consumers would choose to drive less, use alternative travel modes when they are more efficient, and be better off overall as a result. As an analogy, food provides tremendous benefits. However, this does not necessarily mean that increased eating is good or that food should be subsidized.