Nowadays, when new vehicles are developed, like personal cars, buses and heavy-duty trucks, much of the development are done using computers. Instead of building new components and concepts as prototypes and testing them physically out in the world, like it used to be, they are built as mathematical models and tested virtually. This is both faster and less resource demanding, and many more concepts can be tested in the same amount of time. In the end, it means that goals and targets that are otherwise very hard to reach, like zero net CO2 emissions or fully automated driving, may become possible to achieve in the long run.
However, there are some issue with testing things in a virtual world, that does not exist in the physical counterpart. Namely the world itself. Not only must the vehicle (or component, if working with parts and subsystems) be modelled mathematically, but the surroundings and their effects must be considered too. In the real world, the laws of physics are already there. When a vehicle drives around it is affected by gravitation, aerodynamic resistance, slippery surfaces, rolling resistance, bumps, potholes and a million other things, all the time. In addition, there is a driver at the helm, with his or her ideas about how to manoeuvre, where to go and how fast to get there.
In a virtual setting, all these things must be described manually, otherwise they will not show up. It is important to get them right, so that the virtual vehicle is used in a realistic way. If this is fulfilled, then there is a good chance that the technical designs and solutions that are developed, work in the manner that they are supposed to, for example by lowering the CO2 emissions in the predicted way. On the other hand, if the virtual vehicle is not used in realistically, then it becomes very difficult to develop effective solutions, because there is a high risk they do not work as expected. In this thesis, we look at a couple of ways that the road, the surroundings, the traffic and the transport mission can be described mathematically.
One particularly interesting way of doing this, is to pretend that the road consists of a bunch of properties that behave randomly, much like the roll of a die. The different properties, like the hills and the valleys, the curves, the unevenness, and the road signs, behave in their own way - the dice are different - so the randomness can be fitted to the individual properties. When this randomness is measured, we can then start to predict what a road should look like (on average and something about how it varies) and model it realistically in the virtual world.