拖拉机“黑车”现象的思考李绪华用证管现，历来是农机监理工作的五点＿近几年来，仍有相当一部分无牌拖拉机行驶在城乡道路上，作业于田间，这部分拖拉机为什么不挂牌呢？原因是多方面的，受多种因素的制约。、１．公安、农机、交通部门之间缺乏有效的配合。《中华人民共... Tractor “black car” phenomenon thinking LI Xu-hua is now in charge of management, has always been the work of agricultural supervision of five _ in recent years, there are still a considerable number of unlicensed tractors driving in urban and rural roads, work in the field, why do not this part of the tractor it? ? The reasons are manifold and subject to many factors. , 1 Public security, agricultural machinery, transportation departments lack of effective cooperation. "Chinese people ...