t different stages of Р development in the urban agglomeration, with positive spillover effects before 2014 and negative spillover Р effects after 2014; meanwhile, the impact of spillover effects is greater in Beijing and Tianjin and less so in Р Hebei. Р Key words: Beijing-Tianjin-Hebei Urban Agglomeration; Urban Construction Land Benefit; Р Transportation Infrastructure; Spillover Effect Р Р Р (责任编辑: 黄煌) Р ·32·