Transport itself is a kind of ecological system. Like the environment it requires both diversity and balance and is at its healthiest when offering many different ways of moving goods and people across short and long distances. When all resources are directed into one area (like the automobile), diversity is reduced and so is economic efficiency. More people end up walking long distances, or waiting for buses that never come; others simply give up and decide to stay at home.
The transport network of airplanes, helicopters, hovercraft, trains, boats, ferries, buses, taxis, ski-lifts, etc, can only work if all the parts are well connected. However, the different agencies in charge of the various forms of transport have no incentive to interact, partly because they are in competition with one another and partly because cooperation simply makes life harder for them. This is particularly true along commuting corridors, where trains, buses, mini-buses, ferries and possibly even planes and helicopters compete for the same passenger market. When each mode is operated by an independent agency, there is no particular incentive to provide feeder services to the more inflexible modes, and many services are even reluctant to provide good feeder services to rapid transit trains and ferries because their commuter lines are their most lucrative lines. Similarly, in many cities of the developing world, mini-buses and colectivos provide transportation along the main commuting corridors, competing for passengers with the buses. This leaves the mainlines served by small vehicles, while almost empty buses reach the peripheral lines - usually because the public bus company is required to serve these areas, even at a loss.
There are clear-cut economic benefits when transport is integrated and matched directly to need. A large bakery in Bogota, Columbia previously used trucks alone to deliver baked goods to its 600 retail outlets. Today the bakery uses huge lorries to distribute to six sub-distribution centres. From there a fleet of small cargo-tricycles deliver the bread and buns to retail shops, cutting distribution costs by half and increasing the jobs.