What was the anticipated increase in number of fatalities when raising a speed limit to 60 mph?

The anticipated increase in the number of fatalities when raising a speed limit to 60 mph is often associated with studies that analyze the relationship between speed limits and road safety. Research indicates that higher speed limits can contribute to an increase in fatal accidents, as higher speeds typically result in more severe collisions and less time for drivers to react to potential hazards.

The percentage of 9% reflects a statistically significant correlation observed in data that suggests that every increase in speed limit leads to a corresponding increase in fatalities within that range. This relationship is well-documented in traffic safety studies, which consistently show that raising speed limits can increase crash severity and outcomes primarily due to the dynamics of higher speed travel, including increased stopping distances and the potential for higher energy impacts in collisions.

In contrast, lower percentages would indicate less risk associated with speed increases, which does not align with the established evidence supporting the 9% figure as a reasonable estimate of the potential increase in fatalities when speed limits are raised to such levels.