I think your question has two aspects. First of all, in order to know the hazard, you have to observe it and you have to experiment. Then in order to make an assessment, you have to integrate it, and then numerically assess it and make it simple to write the risk assessment.
In that case, you have to do it properly, but you can decrease the cost by going to a pilot study first in several targeted areas, and then do the more comprehensive study, in the same way as Germany and some of the other European countries are doing. By doing that, they actually don't increase the cost necessarily, but they increase the quality of the data.