Logistics Planning & Scheduling

Why is Logistics Planning Hard?

With the exception of logistics planners, people generally do not realise how difficult it is to create a good transport schedule.

There are all the operational complexities of time constraints, vehicle constraints, driver rules, customer requirements etc., but on top of that the actual size of the problem to be solved is much larger than you might think.

The so-called "vehicle routing problem" is a major mathematical challenge and thousands of research papers have been written on the subject. This brief summary gives a quick explanation of why.

Vehicle routing - harder than you think

Even the seemingly simple case of a single vehicle doing a delivery round to customers is a big problem to solve if you need to visit more than a handful of locations.

The number of possible routes the vehicle could take to visit all the sites is much larger than might be expected, making it almost impossible to work the best one when the number of locations is reasonably large. Even for 8-10 locations the number of possible options is surprisingly big.

The images below illustrate how the size of the problem grows faster than exponentially with the number of visits.

Vehicle Routing Algorithms

The example above is known as the Travelling Salesman Problem and has been studied for many years. Wikipedia has a good summary of the theory and some of the research techniques used to tackle it.

The travelling salesman problem is very important for commercial logistics applications also, and MJC² has developed a wide range of sophisticated vehicle routing algorithms that are built in to our scheduling and optimization software.

These algorithms are used in our commercial toolsets such as DISC as part of the optimization process for large logistics and distribution networks.