江苏省高速公路网的统计数据表明,从2004年到2006年,两轴中型货车在空驶状态下的平均质量逐年下降。5轴半挂列车(4×2牵引车带3轴半挂车)的空驶平均质量,2006年比2004年减轻4％。江苏省地处我国公路网中心区位,该省高速公路上大部分货车来自其他省份,所以其高速公路网的统计数据表明,我国货 The statistics of Jiangsu Expressway Network show that from 2004 to 2006, the average quality of two-axle medium-sized trucks in empty driving conditions has been declining year by year. The average quality of the 5-axle semitrailer (4x2 tractor with 3-axle semitrailer) lost 4% in 2006 compared to 2004. Jiangsu Province is located in the center of China’s highway network. Most of the trucks on the province’s expressways come from other provinces. Therefore, the statistical data of its expressway network shows that China’s cargo