North Carolina RADAR State Practice Exam

At what speed does the probability of a fatality in a crash roughly double from its previous value?

1. From 30 mph to 45 mph

2. From 50 mph to 70 mph

3. From 45 mph to 60 mph

4. From 40 mph to 55 mph

The correct answer is: From 45 mph to 60 mph

In analyzing the data surrounding speed and the probability of fatalities in crashes, research indicates that the likelihood of a fatality tends to significantly increase as speed increases. The critical threshold at which this probability roughly doubles is generally observed between the speeds of 45 mph and 60 mph. At these speeds, the severity of accidents typically rises due to factors such as increased stopping distances, higher impact force during collisions, and the greater likelihood of losing control at higher velocities. Thus, the progression from 45 mph to 60 mph exemplifies a substantial increase in risk. This doubling effect is a key point in traffic safety studies, emphasizing the heightened danger associated with higher speeds on roadways. Other intervals, such as from 30 mph to 45 mph or from 50 mph to 70 mph, do not exhibit the same level of probabilistic increase that is specifically observed between 45 mph and 60 mph. Hence, the choice that indicates the transition where fatality risk doubles is indeed substantiated by the statistics and findings in traffic safety research.