Whenever the maximum velocity of any one type of consumer vehicle grows beyond a certain mph, the travel time and the cost of transportation for the median commuter is increased. If the maximum velocity at any one point of a commuter system goes beyond a certain mph, most people are obliged to spend more time in traffic jams, or waiting for connections, or recovering from accidents. They will also have to spend more time paying for the transportation system they are compelled to use.As with transportation where our obsession with getting there faster often only slows us down (and more examples are available), the promise of immediate information doesn't always correspond to reality. Flash presentations download quickly, but was the effort demanded to prepare them actually necessary in order to get some basic information across to us? Sometimes focusing on the bigger picture puts givens in a very different light.The critical velocity depends to a certain extent on a variety of factors: geography, culture, market controls, level of technology, and money flow. With so many variables affecting a quantity, it would seem that its value could fluctuate over a very wide range. Just the contrary is true. Once it is understood that we refer to any vehicular velocity in the transportation of people within a community, we find that the range within which the critical velocity can vary is very narrow. It is, in fact, so narrow and so low that it seems improbable and not worth the time of most traffic engineers to worry about.
Commuter transportation leads to negative returns when it admits, anywhere in the system, speeds much above those reached on a bicycle. Once the barrier of bicycle velocity is broken at any point in the system, the total per capita monthly time spent at the service of the travel industry increases.