县域周边大中城市群有2亿多人口的消费市场。

The peripheral large urban of the county has the consumer market of 2 million populations.

力挺HSR项目的主要理由之一是：21世纪的美国已经不再是一个由城市和郊区组成的国家了，而变成了城市建设研究学者理查德·佛罗里达所称的“特大城市群”。

One of the key ideas fueling HSR is that the U.S. in the 21st century has grown beyond a country of cities and suburbs to what urban-studies expert Richard Florida calls "mega-regions."