| Assuming that a constant travel-time
budget, geographic constraints and short-term infrastructure constraints persist
as fundamental features of global mobility, what long-term results can one
expect? In high-income regions, {{U}}(21) {{/U}}North America, our
picture suggests that the share of traffic{{U}} (22) {{/U}}supplied by
buses and automobiles will decline as high-speed transport rises sharply. In
developing countries, we{{U}} (23) {{/U}}the strongest increase to be in
the shares first for buses and later for automobiles. Globally, these{{U}}
(24) {{/U}}in bus and automobile transport are partially offsetting.
In all regions, the share of low-speed rail transport will probably continue its
strongly{{U}} (25) {{/U}}decline. We expect that throughout the period 1990～2050, the{{U}} (26) {{/U}}North American will continue to devote most of his or her 1.1-hour travel-time{{U}} (27) {{/U}}to automobile travel. The very large demand{{U}} (28) {{/U}}air travel (or high-speed rail travel) that will be manifest in 2050{{U}} (29) {{/U}}to only 12 minutes per person a day; a little time goes a long way in the air. In several developing regions, most travel{{U}} (30) {{/U}}in 2050 will still be devoted to nonmotorized modes. Buses will persist{{U}} (31) {{/U}}the primary form of motorized transportation in developing countries for decades. {{U}}(32) {{/U}}important air travel becomes, buses, automobiles and{{U}} (33) {{/U}}low-speed trains will surely go on serving vital functions. {{U}}(34) {{/U}}of the super-rich already commute and shop in aircraft, but average people will continue to spend most of their travel time on the{{U}} (35) {{/U}}. |