投资、消费、出口被喻为拉动国家经济增长的“三驾马车”。而在地区生产总值支出法核算中,对应国家层面货物和服务净出口的是净流出指标,不仅包括本地区对境外的货物和服务净出口,还包括本地区与国内其他地区间的货物和服务净流出额,说明国内地区间贸易也是地方经济的重要组成部分。因此,作为地方而言,拉动经济增长的不仅有投资、消费和外贸出口,还有开拓国内市场、扩大地区间贸易净流出额这一“第四驾马 Investment, consumption, exports have been hailed as ”troika " driving the country’s economic growth. In GDP accounting for GDP, the net exports corresponding to the net export of goods and services at the national level are indicators of net outflow, including not only the net exports of goods and services to the region from the region, but also goods between the region and other parts of China The net outflow of services shows that intra-regional trade is also an important part of the local economy. Therefore, as a local area, not only economic growth but also investment, consumption and foreign trade exports as well as opening up the domestic market and expanding the net outflow of trade between regions are the fourth driving force