A textbook on highway engineering once said that there are three topics to consider in road design: the vehicle, the user and the road. We can add two more to this list:
- Road standards – There are very many of these. They may contradict each other, be out of date or simply wrong
- The person designing the road – who may misread the road standards, or make human errors when preparing the design
So for example, any investigation of a road traffic accident should include a look at the design of the road, the road standards used in preparing it, and perhaps the person / or organisation which designed it.