As maintenance and operation costs increase with usage over time, equipment is replaced when the value of new equipment is more attractive. Some methods have been developed to solve this problem. In the public transport sector, such problems are frequently analyzed by fleet managers and determined by bus age restriction regulations. We propose an Integer Programming model that integrates both budgetary and environmental constraints (CO₂ emissions) which, as far as we know, have not previously been studied in conjunction. The study aims to determine the optimal replacement plan for a fleet of diesel buses of different size, age, maintenance costs and emissions rates, with new (less polluting) diesel buses over a time horizon of 50 years. The results indicate that it is possible to reduce emissions with a low annual budget using an optimal replacement policy.

随着维护和运营成本随着使用时间的增长而增加，因此当新设备的价值更具吸引力时，便会更换设备。已经开发出一些方法来解决该问题。在公共交通部门，此类问题经常由车队经理进行分析，并由巴士年龄限制规定来确定。我们提出了一个整合了预算和环境约束（CO ₂据我们所知，以前没有进行过联合研究。该研究旨在确定不同大小，年龄，维护成本和排放率的柴油公交车队的最佳更换计划，并在50年的时间范围内使用新的（污染较小的）柴油公交车。结果表明，采用最佳替代政策可以以较低的年度预算减少排放。