We will discuss a model for the exposure factor below. A stands for the probability of getting in an accident at any given time. It is obviously dependent on speed as well as some other factors that we discuss below. It will depend on speed. However, it is possible to analyze how the risk depends on speed by making some reasonable assumptions about the risk and exposure factors.
Exposure here is speed-independent.
What is speed-dependent is the accident risk, A. Your ability to avoid a hazard will be reduced at higher speeds. More realistic models of the accident risk should allow for rapid increase in A at speeds above the mechanical limit of the vehicle. I will disregard this effect here because I believe most cars still behave quite competently at 80 mph which is the highest traffic speed I will dare to consider. K. It is a chance to get killed or gravely injured in an accident when we already know the accident occurs. This is the quantity crash tests attempt to measure.