local authorities是什么意思啊请大家顺帮我翻译个句子,With the increase in auto production,private turnpike（收费公路） companies under local authorities began to spring up,and by 1921 there were 387,000 miles of paved roads.

local authorities是什么意思啊
请大家顺帮我翻译个句子,
With the increase in auto production,private turnpike（收费公路） companies under local authorities began to spring up,and by 1921 there were 387,000 miles of paved roads.

local authorities:地方政府部门
翻译如下：
随着汽车产量的增加,地方政府主管私营公路收费公司如雨后春笋般出现了.到1921年已经有387家这样的私营公司,铺路长达000（这个数字肯定不正确,楼主要改一下）英里.