What percentage of fatalities were expected with a 5 mph increase in the national speed limit?

A 5 mph increase in the national speed limit is associated with an estimated increase in fatalities due to the higher speeds leading to more severe accidents. Research has shown that even a small increase in speed can have a significant impact on road safety, as the kinetic energy involved in collisions increases with speed.

Studies have indicated that for each 1 mph increase in speed, the risk of a fatal crash rises by about 2% to 3%. When applying this data to a 5 mph increase, the cumulative effect results in an estimated increase of about 9% in fatalities. This figure reflects both the likelihood of accidents occurring and the severity of those accidents when they do happen at higher speeds.

By understanding the relationship between speed and crash outcomes, transportation safety advocates emphasize the need for careful consideration of speed limit adjustments, highlighting how even minor changes can have major implications for public safety on the roads.