Routing Problems with Time Dependencies or how Different are Trash Collection or Newspaper Delivery from Street Sweeping or Winter Gritting?

The focus of this paper is on the windy rural postman problem with the additional option to zigzag street segments during certain times of the day. If a street is narrow or traffic is light, it is possible (and often desirable) to service both sides of the street in a single pass by zigzagging. However, if a street is wide or traffic is heavy, we must service the street by two single traversals. For some streets, we further assume that they may only be zigzagged early in the morning when the traffic is low. Real-life applications arise, among others, in trash collection and newspaper delivery. This problem is solved by transforming it into a node routing problem and present a mathematical formulation.