Does Proximity to Expressways Improve Manufacturing Productivity? Evidence from Chinese Firms
利用中国长三角地区企业级数据，研究发现高速公路显著提升了制造业全要素生产率，且距离越近效果越强，主要通过降低库存成本、提高盈利能力和产业集聚实现，但对产品创新影响不显著。
By matching the geocoded data of firm-level productivity and county-level expressway networks in China’s Yangtze River Delta region, we establish a difference-in-differences model to investigate the impact of expressways on manufacturing firm productivity. The results show that expressways boost manufacturing firms’ total factor productivity, with firms closer to expressway services achieving more significant productivity increases compared to those farther away. The results remain robust after controlling for the endogeneity problem using an instrumental variable approach. Expressways promote firm productivity by reducing inventory costs and increasing firm profitability and regional industrial concentration, whereas their effect on product innovation is insignificant. We also find heterogeneity in the impact of expressways on firm productivity, with firms in peripheral counties and in labor-intensive industries receiving a weak productivity-enhancing effect, while firms in central regions and those with high transport dependency benefit more.