求翻译：A stable and efficient transportation environment requires that carriers provide essential services at reasonable cost. Because of the direct impact of transportation on economic success, governments have traditionally been more involved in the practices of carriers than in most other commercial enterprises. In some situations, such as the United States Postal Service, government is directly involved in providing the transportation service. Government traditionally regulated carriers by restricting markets they could service and regulating prices they could charge. Governments also promote carrier development by supporting research and providing right-of-way such as road- ways and airports. In some countries government maintains absolute control over markets, services, and rates. Such control allows government to have a major influence on the economic success of regions, industries, or firms.是什么意思？

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